mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-10-26 10:57:38 +08:00
master
1473
Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 Linus Torvalds
|
c5fd5e67c7 |
Merge tag 'mm-stable-2026-10-19-21-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- "selftests/mm: improve khugepaged coverage" (Kiryl Shutsemau):
Give khugepaged a proper workout. Extend the tests to all supported
mTHP orders, check exactly which windows collapsed, and make scan
completion deterministic. Race collapse against faults, pinning, fork
and remap; verify that the contents survive.
Add coverage for whole-page-table zaps and memory pressure too.
- "selftests/mm: separate GUP microbenchmarking from functional testing"
(Sarthak Sharma):
Untangle GUP benchmarking from correctness testing. Move the
benchmark into tools/mm, add a standalone harness-based GUP selftest,
and move shared helpers into tools/lib/mm. Give each tool one job
instead of mixing timing measurements with correctness checks.
Cover the mapping, pinning and batch-size combinations explicitly.
- "mm: Switch device DAX to section-based vmemmap optimization" (Muchun
Song):
Apply section-based vmemmap optimization to device DAX. Rework the
backing metadata layout to save memory while preserving the handling
of device memory hotplug and its different alignment and lifetime
requirements.
- "mm: Introduce section-based vmemmap optimization for HugeTLB"
(Muchun Song):
Cut the memory consumed by HugeTLB's struct page array with
section-based vmemmap optimization. Arrange the metadata so large
huge pages need fewer backing pages, while keeping initialization,
teardown and the various hugepage configurations straight.
- "mm/huge_memory: clean up and decouple the anon and file split
helpers" (Kairui Song):
Separate anonymous and file-backed folio splitting, which have rather
different locking and bookkeeping requirements. Move the work into
separate helpers, drop dead checks and tidy swap-cache handling. Fix
error paths, including one that could leave a folio frozen.
Keep the swap cache cases separate from file-cache splitting.
- "mm: Unconditional per-VMA locks and cleanups" (Dave Hansen):
Make per-VMA locking unconditional and clean up the old conditional
code around it. This removes configuration-dependent plumbing and
lets callers depend on one locking model rather than carrying both
cases along.
- "memcg: remove the v1 soft limit" (Shakeel Butt):
Remove the old cgroup v1 memory soft-limit machinery. This has long
since been superseded by the newer memory-control interfaces; hauling
around a separate reclaim scheme for it no longer buys us much.
- "read proc/pid/smaps_rollup under per-vma lock" (Suren Baghdasaryan):
Read /proc/PID/smaps_rollup using per-VMA locks where possible,
rather than holding mmap_lock across the entire walk. Retain the
contention fallback and add tearing tests. This considerably reduces
latency when another thread is busy changing its mappings.
- "mm/damon: introduce data access-as-a-data attribute" (SJ Park):
Teach DAMON to expose memory access observations as data attributes,
making them available to the probe and filtering machinery. Extend
the interfaces, documentation and tests so the new information can be
used rather than merely collected.
- "Remove PG_private by using page/folio->private checks instead" (Zi
Yan):
Get rid of PG_private and use the folio's private pointer to say
whether private data is attached. Convert the filesystem users,
including erofs, f2fs and md, and clean up the old accessors and
flags. There are a few special cases, notably swapcache and hugetlb,
which need explicit care.
- "mm: make userland page table freeing RCU-safe" (Lorenzo Stoakes):
Make freeing userspace page tables safe against RCU readers. Sort out
the page-table lifetime and locking rules so walkers cannot stumble
over freed tables while mappings are being torn down.
- "make unused huge shrinker memcg aware" (Qi Zheng):
Make shmem's unused-huge-folio shrinker aware of memory cgroups, so
reclaim can find those folios under the right memcg. Wire up the
per-memcg tracking and its lifetime rules, and give the shrinklist
its own lockdep class to avoid spurious dependency reports.
- "mm: Drop pxd_ERROR()" (Anshuman Khandual):
Remove the old pxd_ERROR() page-table checks and their
architecture-specific baggage. Simplify the common page-table
interfaces and callers now that these checks no longer serve a
useful purpose.
- "memcg: group struct fields by access pattern" (Shakeel Butt):
Rearrange memcg's hot and cold fields according to how they're
actually accessed. Keep frequently updated counters and their
neighboring state from fighting over cachelines and reduce needless
cacheline traffic.
- "mm/damon/core: fix the size charged for a filter-trimmed region"
(Donggeun Yoo):
Fix DAMOS quota accounting when a filter trims a monitoring region.
Charge only the part left after filtering, not the original region,
and add KUnit coverage. Previously the excluded memory could eat into
the quota and make schemes run more slowly than requested.
- "mm/damon: add kunit and selftests for probes and probe weights" (SJ
Park):
Add more tests for DAMON probes and their weights, including
validation and the results reported to userspace. This is mostly
about catching regressions in the newer probe infrastructure before
they become harder to diagnose.
- "mm: memcontrol: constify the read side of the read side of the memcg
API" (Tal Zussman):
Mark the read-only parts of the memcg interface const, from folio and
lruvec accessors to counters and swap helpers. Most of this is
mechanical, but it makes the contracts clearer and lets the compiler
catch accidental writes.
- "mm/damon/vaddr: support {prep,apply}_probes" (SJ Park):
Support the new prepare/apply probe operations in DAMON's
virtual-address backend. This brings vaddr monitoring into line with
the probe infrastructure and makes the added probe types useful there
too.
- "mm/mglru: clean up folio counters and flag usage" (Kairui Song):
Simplify MGLRU's folio counters and flag handling. Remove redundant
accounting paths and make the state transitions easier to follow
without changing the intended reclaim policy.
- "arch, mm/execmem: resolve confusion about set_direct_map_valid_noflush()"
(Mike Rapoport (Microsoft)):
Clarify and straighten out the set_direct_map_valid_noflush()
interface across architectures and execmem. Make the requested
mapping changes and the callers' expectations agree, rather than
relying on subtly different architecture behavior.
- "mm: zswap: free cold writeback folios promptly" (Alexandre Ghiti):
Free zswap writeback folios as soon as their disk write completes.
They are cold temporary buffers, so putting them on the LRU only
makes reclaim rediscover them later. Extend swap-cache dropbehind and
let zswap keep these folios off the LRU altogether.
- "mm: gup: cleanup gup_fast call chain" (Aristeu Rozanski):
Clean up the GUP-fast call chain and simplify how the fast-path
helpers pass their arguments and results around. Keep the page-pin
behavior the same while making the call sequence easier to maintain.
- "mm: optimize zone-device memmap initialization" (Li Zhe):
Speed up initialization of zone-device struct pages. Avoid redundant
work when setting up large device-memory ranges, where touching every
descriptor can get expensive.
- "mm/zswap: shrink zswap_entry via a pool id" (Jianyue Wu):
Reduce the size of zswap_entry by storing a compact pool identifier
instead of a full pointer. Keep the pool lookup and lifetime handling
correct while saving per-entry metadata.
- "mm/damon: support access monitoring of hugetlb-backed memory"
(Krishna Iyer):
Let DAMON monitor hugetlb-backed memory too. Extend the relevant
access checks and add coverage so those mappings no longer fall
through a hole in the monitoring machinery.
- "mm/execmem: fixes and cleanups for the ROX cache" (Mike Rapoport):
Tidy execmem's read-only-executable cache and fix its handling of the
awkward allocation and release cases. The aim is to make the cache's
ownership and permission transitions more predictable.
- "zsmallc: remove old object read API" (Sergey Senozhatsky):
Drop zsmalloc's old object-read API and move its remaining users to
the supported access mechanism. This removes a duplicate interface
which we no longer need.
- "mm/mempolicy: stop copying state in the interleave paths" (Gregory
Price):
Stop copying mempolicy state in the interleave paths when a reference
to the existing policy will do. This avoids extra work and makes the
ownership rules less obscure.
- "mm/mglru: speed up inc_min_seq() and fix cold/hot inversions" (Barry
Song):
Make MGLRU's generation advancement cheaper and fix cases where cold
and hot folios end up in the wrong order. Adjust the counter and list
handling so reclaim doesn't keep passing over the better eviction
candidates.
- "mm: Fix MF_DELAYED handling on memory failure" (Lisa Wang):
Treat MF_DELAYED as a partially completed memory-failure operation,
not an outright failure. Propagate that result correctly through
shmem and the generic handler, fix the extra-reference accounting,
and add tests for the resulting SIGBUS behavior.
- "tools/mm/page_owner_sort: fix --sort, add module filter, improve
usage" (Ye Liu):
Fix page_owner_sort's --sort handling, add module-based filtering and
make the usage output more helpful. This makes the tool less
frustrating when tracking down who is holding on to pages.
- "mm/damon: move damos filter range arguments validation to core" (SJ
Park):
Move DAMOS filter range validation into the core, where all callers
can share it. Also close the sysfs read-twice races which could pass
inconsistent ranges, and add tests for invalid input.
- "mm/damon: misc cleanups" (Zenghui Yu):
Clean up a collection of small DAMON rough edges in the core,
interfaces and tests. No large behavior change here, just simpler
code and fewer opportunities for confusion.
- "mm/damon: cleanup code, add test cases, and update guidances in
docs" (SJ Park):
Clean up DAMON's core and interfaces, add missing test cases and
bring the documentation into line with the code. These changes should
make the newer facilities easier to understand and maintain.
- "mm/damon: introduce hugepage_size probe filter" (SJ Park):
Add a DAMON probe filter for hugepage size. Let users select a range
of folio sizes through sysfs, validate the range and document the new
interface, so monitoring can concentrate on memory backed by the
desired hugepage sizes.
- "selftests/mm: pagemap_ioctl test fixes and cleanups" (Zenghui Yu):
Fix some pagemap ioctl test assumptions and clean up their setup and
reporting. Make failures point to the operation that went wrong
rather than to test harness bookkeeping.
- "mm: avoid large folio splits when swap is unavailable" (Johannes
Weiner):
Avoid splitting large folios merely to attempt swap when no swap
space is available. There is little point paying for an expensive
split when reclaim cannot actually swap the resulting pages out.
- "mm: workingset: fix the shadow node budget under MGLRU" (Hui Zhu):
Fix the workingset shadow-node budget with MGLRU enabled. Keep the
shadow entries within the intended limits so refault tracking does
not quietly consume more metadata than it should.
- "selftests/mm: TAP output and global-state fixes" (Song Hu):
Fix selftests which produce misleading TAP output or fail to restore
global settings after a run. A test ought to leave the system as it
found it, particularly when a whole suite follows behind.
- "mm: remove page_swap_entry()" (Tal Zussman):
Remove page_swap_entry() and convert its remaining users to the folio
and swap-entry helpers. Lose an old page-level interface and make the
swap paths a little more consistent.
- "mm: refactor zonelist constructors and iterators" (Gregory Price):
Refactor the zonelist construction and walk helpers to reduce
duplicated logic. Keep the allocation ordering rules intact while
making it clearer how zones are selected.
- "mm: kmemleak: batch the struct page scan" (Breno Leitao):
Scan adjacent struct pages in batches instead of taking kmemleak_lock
once for every single page. This preserves scan coverage and the
lock-hold bound, while cutting overhead substantially on debug
kernels.
- "mm/damon: misc improvements in tests and documents" (Zenghui Yu):
Fix some DAMON selftests which leave kdamond running or fail under
Python safe-path mode, and improve the KUnit coverage and
documentation. Nothing especially glamorous, but these are worth
doing.
- "mm/damon: introduce probe_hits_wsum DAMOS core filter" (SJ Park):
Add a DAMOS core filter using weighted probe-hit counts. This gives
schemes another way to select regions based on what the monitoring
probes observed.
- "mm/mglru: fix ineffective memory protection for non-kswapd reclaim"
(Ridong Chen):
Fix MGLRU's memory protection handling for reclaim outside kswapd.
The protection settings weren't having the intended effect in these
paths, leaving protected memory more exposed than requested.
- "mm/damon: improve readability, clarity and test coverage" (SJ Park):
Simplify a handful of DAMON core helpers, clarify their behavior and
expand test coverage. There are no intended userspace-visible changes
in this batch.
- "mm: replace PF_KCOMPACTD/PF_KSWAPD with kthread_func()" (Kefeng
Wang):
Stop identifying reclaim and compaction workers through the PF_KSWAPD
and PF_KCOMPACTD task flags. Use their kthread functions instead and
remove the redundant flag plumbing.
- "mm/hugetlb: fix surplus accounting and availability checks during
demotion" (Longlong Xia):
Fix HugeTLB surplus accounting and availability checks when demoting
huge pages. Keep the counters and reservation decisions consistent as
one huge page turns into several smaller ones.
- "mm/damon: add kunit tests for probe_hits handling and probe params
validation" (Jason Angelov):
Add KUnit tests for DAMON probe-hit handling and invalid probe
parameters. These cover edge cases that were too easy to miss in
ordinary monitoring tests.
- "mm/damon: fix misc bugs in kunit, quota goals and sysfs refresh_ms"
(SJ Park):
Fix a few DAMON bugs in KUnit tests, quota-goal handling and the
sysfs refresh interval. Small fixes, but the incorrect results and
control behavior were real.
- "mm: zswap: optimize zswap invalidate and store" (Kefeng Wang):
Simplify zswap's invalidate and store paths to avoid avoidable
lookups and work. Keep the entry lifetime rules intact while making
those frequent operations cheaper.
- "mm: replace custom ratelimiting logic" (Pedro Falcato):
Replace hand-rolled MM rate limiting with the common kernel helpers.
There is no need to maintain another local version of the same
mechanism.
- "mm/vmalloc: minor cleanups" (Ye Liu):
Tidy some vmalloc initialization and reporting code, and pull
duplicated vmap-area insertion work into a helper. No functional
changes are intended.
- "mm/mglru: clean up isolate_folios for readability and clarity"
(Ridong Chen):
Clean up MGLRU's isolate_folios() so the decisions are easier to read
and verify. Keep reclaim behavior unchanged while removing
unnecessary twists in the control flow.
- "Catch automatic storage in IDA and Maple Tree definitions" (Yury
Norov):
Catch IDA and maple-tree definitions placed in automatic storage
where the lifetime rules are wrong or easy to get wrong. Add checks
so such mistakes are harder to slip through unnoticed.
- "mm, swap: some random fixes and cleanups" (Kemeng Shi):
Fix and simplify a few unrelated swap paths, removing redundant work
and tidying up error handling. A small collection of things which
were better fixed than left lying around.
- "mm/page_io: folio conversion cleanups" (Tal Zussman):
Finish some page-to-folio conversions in swap I/O, removing obsolete
wrappers and using folio operations consistently. The I/O behavior is
intended to remain the same.
- "mm/swap: skip empty clusters in the swapoff scan" (Youngjun Park):
Skip empty swap clusters during swapoff instead of walking slots
which have nothing to release. This avoids pointless work on sparsely
used swap devices.
- "mm: trace: decode architecture-specific VMA flags" (Meijing Zhao):
Teach the VMA trace output to decode architecture-specific flags,
rather than leaving them as unexplained bits. That should make
tracing a good deal more useful when debugging unusual mappings.
- "mm, swap: don't spin on a bad swap entry" (Breno Leitao):
Stop repeatedly retrying a swap entry which is already known to be
bad. Make the error path terminate cleanly instead of wasting CPU
chasing an entry that cannot be used.
- "mm/page_isolation: fix UBSAN shift-out-of-bounds in
isolate_single_pageblock" (Qi Xi):
Fix an out-of-range shift in isolate_single_pageblock() and tighten
its associated boundary handling. UBSAN found the issue; the result
should be more robust pageblock isolation.
- "mm: khugepaged: fix tracepoint UAF" (Vernon Yang):
Fix a use-after-free in khugepaged tracepoint handling. Make sure the
information recorded by tracing stays valid for as long as the trace
event needs it.
- "mm/damon: fix DAMOS bugs in core, paddr and vaddr" (SJ Park):
Fix several DAMOS problems across the core and physical- and
virtual-address backends. The changes close error cases and bring the
implementations back into agreement.
- "mm/hugetlb_cgroup: move the per-node usage along with the folio"
(Hongfu Li):
Move HugeTLB per-node usage accounting when folios migrate between
nodes or are reparented to another cgroup. Otherwise numa_stat can
retain stale charges and even underflow when the folio is freed.
- "docs/core-api: memory-allocation: add k[mz]alloc_obj() and clarify
kmalloc" (Mike Rapoport):
Document the typed k[mz]alloc_obj() allocation helpers and clear up
some kmalloc guidance. Make it easier for callers to choose the right
interface.
- "selftests/mm: Validate selections and scope memfd_secret setup"
(Tianyi Chen):
Check selftest selections before running and confine memfd_secret
setup to the cases that actually need it. Avoid confusing failures
caused by the test harness itself.
- "mm/damon: move zero damos quota target_value handling to the core
layer" (SJ Park):
Handle a zero DAMOS quota goal target in the core rather than making
each user of the interface invent its own rule. Keep quota decisions
consistent across callers.
- "mm/damon: Introduce a huge page collapsing mechanism using auto
tuning" (Asier Gutierrez):
Add an auto-tuned DAMON mechanism for collapsing huge pages. Use
monitoring feedback to decide when collapse is worthwhile rather than
forcing one fixed policy onto every workload.
- "kmemleak: fix stale documentation and raise the verbose default"
(Breno Leitao):
Bring the kmemleak documentation up to date and require a third
confirming scan before verbose kernels print a suspected leak. The
extra scan helps suppress transient false positives in noisy debug
builds.
- "mm/memory: improve insert_pages() error handling" (Avi Weiss):
Tighten insert_pages() error handling so partial failures are
reported and cleaned up consistently. The caller should not have to
guess how far the operation got.
- "mm/damon: allow NULL or unstarted damon_ctx parameter for
damon_call()" (SJ Park):
Make damon_call() handle NULL and not-yet-started contexts safely.
Simplify the rules for callers and avoid an indefinite wait on an
invalid state.
- "mm/damon: introduce pgidle_set probe filter type" (SJ Park):
Add a pgidle_set DAMON probe filter, giving monitoring users another
way to select pages by their idle-tracking state. Wire it through the
filter interfaces and tests.
- "mm/damon/core: remove unused helper functions" (Cheng-Han Wu):
Remove DAMON core helpers which no longer have callers. Keep the API
surface smaller rather than retaining dead code just in case.
- "mm: stop calling pmd_folio() on special PMDs" (Gregory Price):
Avoid calling pmd_folio() on special PMD mappings that have no struct
page. The old assumption could fault in procfs walkers; use the
normal-folio checks and handle those mappings properly.
- "mm: remove three unused helpers from mm.h" (Tal Zussman):
Remove three unused helpers from mm.h. Fewer obsolete interfaces for
the next person to stumble over.
- "mm/damon: improvements in efficiency, error handling, documents"
(Liew Rui Yan):
Skip needless DAMOS quota work once the quota is full, propagate a
missing sysfs error and tidy a couple of comments. The ignored error
could make a monitoring-start request appear successful when it
wasn't.
- "docs/mm/damon/design: add explanation of nr_snapshots" (Liew Rui
Yan):
Explain DAMON's nr_snapshots accounting in the design documentation
and straighten out the associated terminology. Make it clearer what
users should expect from that counter.
- "selftests/cgroup: fixes for test_zswap on single core VM" (Wilson
Felipe Pereira):
Fix two test_zswap failures on single-CPU VMs. Wait for the exiting
child's cgroup to become unpopulated before reconfiguring it, and
avoid another test assumption which breaks under constrained
scheduling.
- "docs/ksm: fix advisor documentation and comment" (Jinjiang Tu):
Correct the KSM advisor documentation and a misleading code comment.
Keep the description aligned with how the advisor actually works.
- "Fix bugs in HugeTLB allocation when mem_cgroup_charge_hugetlb()
fails" (Ackerley Tng):
Fix HugeTLB allocation cleanup when the memcg charge fails. Make sure
failure exits undo what was allocated rather than leaving stale
accounting or resources behind.
- "mm, memcg: fix memory.peak reset clobbering other fds' watermark"
(Ridong Chen):
Fix memory.peak reset handling so resetting one file descriptor
doesn't overwrite the watermark kept for another. Keep those per-open
measurements independent as intended.
- "mm: reject zone device folios in more folio walkers" (Gregory
Price):
Reject zone-device folios in page walkers that cannot safely handle
them. Extend the existing checks rather than assuming every folio has
ordinary system-memory backing.
- "percpu: remove code with no effect" (Sang-Heon Jeon):
Remove a few pieces of percpu code which no longer do anything. There
is no reason to keep maintaining dead paths.
* tag 'mm-stable-2026-10-19-21-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (539 commits)
mm: shmem: assign a lock class to the unused huge shrinklist
mm: vmscan: put rotation-missed folios at the LRU tail
mm: kmemleak: scan the struct page array in MAX_SCAN_SIZE batches
mm: kmemleak: move the struct page scan into a helper
mm/damon: document that a zero sample_interval is accepted
mm/damon: fix typos in comments
mm/damon/sysfs: propagate damon_call() error in turn_damon_on
mm/damon/core: skip quota score setup when the quota is full
mm/damon/tests/core-kunit: test the size charged for a filter-trimmed region
mm/damon/core: charge only the part of a region the filter left
mm: disallow raw PFN mappings of huge/shared zeropage
selftests/mm: zap whole PTE tables in the khugepaged race harness
selftests/mm: add memory-pressure threads to the khugepaged race harness
selftests/mm: race the collapse of windows with holes
selftests/mm: add khugepaged race harness
selftests/mm: check that one khugepaged pass collapses one window
selftests/mm: run every supported collapse order by default
selftests/mm: cover a shared-source collapse write race
selftests/mm: parameterize the mixed-source collapse case by source order
selftests/mm: add order-parameterized khugepaged collapse cases
...
|
||
|
Linus Torvalds
|
f47d223627 |
Merge tag 'vfs-7.4-rc1.sync_close' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull file closing updates from Christian Brauner:
"This makes closing files synchronous for close_range(), exec and exit.
Since fput() was switched to task work every final __fput() of an
exiting task is queued on task work and run from exit_task_work().
exec and close_range() do the same. For a task with a large descriptor
table that is a cmpxchg() and a TIF_NOTIFY_RESUME test-and-set per
file plus a list entry for any later task_work_cancel() to search
under pi_lock, and then a second pass over every struct file that
isn't cache hot anymore by then. Oleg and Neil have pointed this out
over the years.
close_files(), close_range() and close-on-exec now flush and put each
file inline the way close(2) does. Kernel threads aren't affected.
They share init_files which init_task pins forever so their
exit_files() never drops the last reference, and their fput() keeps
punting to a workqueue. The one place that could put a table from a
kthread context, a failing copy_process(), can't hold the last
reference while the source table is alive.
On a 64 vCPU KVM guest tearing down 4096, 65536 and 1M descriptors
scattered at random positions in the table:
4096 fds 65536 fds 1M fds
exit 1045 -> 895 us 18.9 -> 14.9 ms 429 -> 306 ms
execve, close-on-exec 1393 -> 1190 us 21.4 -> 16.9 ms 471 -> 325 ms
close_range() 1179 -> 988 us 21.9 -> 17.4 ms 484 -> 337 ms
So that is 16-21% or 40-150 ns per closed file, largest at 1M
descriptors. With eight processes tearing down 65536 descriptors each
at once it stays at 16-21% because the second pass over 16 MB of
struct file is what gets expensive when CPUs compete for the cache.
With 32 or 64 processes both kernels are bound by pushing millions of
files through slab and rcu and the difference shrinks to 4-8%. Files
whose own release dominates gain less, 13% for eventfds, 11% for
pipes, 6% for AF_UNIX sockets. close(2) is untouched and will-it-scale
is within 2%.
The spufs coredump support is removed. It was the only reason
do_coredump() unshared the descriptor table. gdb dropped Cell
debugging in 9.1 and binutils in 2.34, the Cell blades are gone and
nothing on the PlayStation 3 produces or reads these notes. With that
unshare_files() goes away, exec installs its private table through the
new switch_files_struct() and the coredump startup completion becomes
a plain thread count waited on with the new wait_var_event_state().
Three fixes for the synchronous close are included. A failed fork
released its files under scx_fork_rwsem and deadlocked against the bpf
link's release. A session leader's exit released its tty before
disassociate_ctty() ran and the foreground job lost its SIGHUP, so the
tty is hung up before the files are closed now. And descriptor tables
are walked from the highest descriptor down which restores the order
the deferred puts had and keeps a few long-standing release ordering
bugs from deadlocking exit"
* tag 'vfs-7.4-rc1.sync_close' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
fs: close files from the highest descriptor down
coredump: factor out coredump_wait_inactive()
exit: hang up the tty before closing the files
fork: release the files of a failed fork after sched_cancel_fork()
coredump: replace the startup completion with a thread count
sched: add wait_var_event_state()
coredump: drop core_state->dumper
fs: make close_cloexec_files() synchronous
fs: rename do_close_on_exec() to close_cloexec_files()
fs: make close_range() synchronous
fs: make close_files() synchronous
fs: add filp_close_sync()
fs: remove unshare_files()
fs: move unshare_fd() to fs/file.c
fs: add switch_files_struct()
coredump: stop unsharing the file descriptor table
fs: don't open-code file_close_fd() in close_fd()
powerpc: remove coredump support
|
||
|
Linus Torvalds
|
018cf9bf78 |
Merge tag 'kernel-7.4-rc1.signal' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull signal handling updates from Christian Brauner:
"This stops TIF_NOTIFY_SIGNAL from interrupting work that can't be
restarted and fixes a bunch of coredump and signal bugs.
TIF_NOTIFY_SIGNAL kicks a task out of an uninterruptible sleep so it
returns to userspace, runs its task work and goes back to sleep. That
breaks coredumps: dump_interrupted() only lets fatal signals interrupt
a dump and writes to a regular file ignore TIF_NOTIFY_SIGNAL. But the
pipe and the socket paths check signal_pending() Adeep down in code
that is shared with regular syscalls and bail. So a crashing process
with io_uring requests in flight loses most of its coredump.
In the selftest an unfixed kernel delivers 357324 of at least 5111808
bytes. And io_uring isn't the only source. klp_send_signals(),
bpf_task_work_schedule_signal(), landlock's tsync, kthread_stop() and
the printk kunit test raise the bit as well, some of them from irq
context against any task. So this can't be fixed per subsystem and the
state has to be per-task and ambient.
Add PF_NO_NOTIFY_SIGNAL and no_notify_signal_save()/restore() helpers
modelled on memalloc_nofs_save(). Inside such a section
signal_pending() ignores TIF_NOTIFY_SIGNAL. Coredumps, the smb send
path, which hand-rolled its own version of this, and the pid namespace
reaper, which busy-looped when the bit kept getting raised, are
converted.
The second part is a set of fixes that fell out of looking at the
coredump code with kres and modelling it in TLA+:
- coredump_finish() woke the parked threads without holding rcu. A
parked thread can exit on a spurious wakeup and be freed before
wake_up_process() takes its pi_lock.
- Only SIGKILL and the freezers interrupt a dump now and the three
freezers agree. Power management and cgroup v1 freezing aborted a
dump while a cgroup v2 freeze either waited for the dump or cut it
short depending on where the core went.
- io-wq set its exit bit without a barrier against the task work that
creates workers. On weakly ordered architectures exit could hang on
worker_done.
- retarget_shared_pending() slingshotted a shared signal to the dumper
when a zapped sibling restored its signal mask. That set
TIF_SIGPENDING on the dumper and truncated the core.
- A tracer could clear the signal mask of a user worker with
PTRACE_SETSIGMASK and inject a coredump signal. An io-wq worker of
an SQPOLL ring dumping core deadlocks the whole group.
PTRACE_SETSIGMASK is refused for user workers now and
__set_task_blocked() enforces the fork-time mask.
- exec cancels io_uring requests before de_thread() so a worker
creation queued as task work can't add a thread to a thread group
that de_thread() just took down.
- No io threads are created from a PF_SIGNALED or PF_POSTCOREDUMP
creator anymore. Such a worker was invisible to zap_process() but
still decremented threads_remaining on exit so the dumper could
leave coredump_wait_inactive() early.
Also included are a comment that do_each_pid_task() needs
tasklist_lock, a READ_ONCE() in pid_alive() and a regression test for
fork() into a pid namespace whose ancestor lost its init"
* tag 'kernel-7.4-rc1.signal' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (21 commits)
pid: use READ_ONCE() in pid_alive()
selftests: pid_namespace: test fork with dead ancestor
pid: document that do_each_pid_task() needs tasklist_lock
signal: enforce the user worker signal mask in __set_task_blocked()
fork: use SIG_KERNEL_ONLY_MASK for the user worker signal mask
fork: don't create io threads once PF_POSTCOREDUMP is set
fork: move the coredump and exec checks into create_io_thread()
exec: cancel io_uring requests before de_thread()
selftests/coredump: expect PTRACE_SETSIGMASK to be refused on a user worker
selftests/coredump: test a user worker as the coredumping thread
ptrace: refuse to change the signal mask of a user worker
selftests/coredump: test shared signal retargeting during a dump
signal: only SIGKILL and the freezers interrupt a coredumping task
signal: don't retarget shared signals in a dying thread group
io-wq: order the exit bit against worker creation task work
coredump: hold RCU while releasing parked threads
pid_namespace: prevent TIF_NOTIFY_SIGNAL from interrupting the reaper
smb: prevent TIF_NOTIFY_SIGNAL from interrupting
selftests/coredump: test that TIF_NOTIFY_SIGNAL doesn't truncate a coredump
coredump: prevent TIF_NOTIFY_SIGNAL from interrupting coredumps
...
|
||
|
Christian Brauner
|
d2bdb9b61b |
fs: let idle threads share init_fs
With nullfs as the real rootfs userspace can pivot_root() away from the
initramfs and unmount it:
chdir(rootfs);
pivot_root(".", ".");
umount2(".", MNT_DETACH);
That's what systemd does and the initramfs is supposed to go away at
that point together with all the memory it uses. But on every machine
with more than one possible cpu the initramfs superblock stays around
forever (cf. [1]). With ramfs as rootfs the unpacked initramfs shows up
as Unevictable in /proc/meminfo, with tmpfs as Shmem, and it is never
freed. In the reports that's between 70MB and 150MB.
The idle threads of the secondary cpus are created by fork_idle() from
smp_init(). That runs in kernel_init(), i.e., in PID 1, after
init_userspace_fs() moved PID 1 from nullfs into the initramfs.
fork_idle() doesn't pass CLONE_FS so each idle thread gets a private
copy of PID 1's fs_struct and with it a reference to the initramfs as
root and as pwd.
pivot_root() relies on chroot_fs_refs() to move everyone whose root or
pwd is the old root over to the new root. Idle threads aren't on the
task list though so chroot_fs_refs() never finds them. They never exit
either. So they keep the initramfs mount and with it the superblock
alive for good. I overlooked this when I added nullfs. Before that the
rootfs could never be unmounted anyway so it didn't matter what pinned
it.
Idle threads are kernel threads and init_task, the idle thread of the
boot cpu, already uses init_fs. So let the idle threads of the other
cpus share init_fs as well instead of copying PID 1's filesystem state.
Note that kernels before 7.3 need a different backport. There PID 1
still shares init_fs with all kthreads so passing CLONE_FS in
fork_idle() is enough. They also have a second pin: devtmpfsd unshares
a copy of the initial mount namespace, initramfs mount included. That
was fixed in commit
|
||
|
Christian Brauner
|
9cd0df397a |
fs: pass flags to copy_fs()
Turn the umh boolean into a flags argument. Idle threads need their own case in copy_fs() as well and that's nicer than a second boolean. No functional changes. Link: https://patch.msgid.link/20261013-work-fs-idle_fs-v1-1-2063d1bcb5aa@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> |
||
|
Linus Torvalds
|
f99005fbed |
Merge tag 'vfs-7.3-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs fixes from Christian Brauner:
"This contains fixes for the current development cycle.
All of them came out of a review of the mount code that started with a
bug report. The review modeled the corner cases of mount propagation,
unmounting and mount reference counting and turned up a lot of bugs.
Most of them years old. Most fixes come with a selftest.
- Rework connected mounts.
A mount that is unmounted together with its parent can stay
attached to the parent to keep its mountpoint covered. That happens
when the mountpoint is removed with rmdir(), unlink() or rename(),
when a detached tree is dissolved, and for locked mounts in any
umount that isn't synchronous, including the teardown of their
mount namespace. The parent then owns the child and drops it on its
own final mntput(). So any reference from the child's superblock
back to one of its ancestors becomes a cycle that is never freed.
A loop device backed by an image on a tmpfs and mounted on that
same tmpfs is enough. Remove the directory the tmpfs is mounted on
from the host, let the container's mount namespace exit, and the
loop device, the tmpfs and the filesystem on the loop device are
leaked for good. The same works with autofs, zram, ecryptfs,
binfmt_misc, fuse passthrough, zloop, a mass storage gadget and md,
and the selftests have reproducers for them. This has been possible
since v4.1. It is also why "put_mnt_ns(): leave mounts connected"
was reverted in -rc5. Keeping every mount of a dying mount
namespace connected made these cycles trivial to create.
Every unmounted mount is now detached from its parent. Where the
mountpoint has to stay covered the mount leaves a cover on the
parent instead, allocated together with the mount. A lookup on the
unmounted parent that hits a cover finds an empty immutable
directory or file on the private nullfs instance. Nothing leads
from a cover to another mount, so no unmounted mount owns another
one and no cycle can form.
This is visible to userspace. A formerly connected mount can no
longer be reached through its unmounted parent and ".." inside it
leads nowhere, as for every other lazily unmounted mount.
With that the private nullfs instance becomes reachable from
userspace, so it now refuses mounts on top, is mounted read-only,
and refuses fsnotify marks and file locks. Its inodes are shared by
every holder and a watch or a lock would otherwise reach across
users. may_decode_fh() now also decides its subtree check under a
single mount_lock hold, as a racing umount could otherwise let it
decode into what a locked child covered.
- umount:
* Don't silently unmount busy mounts.
Since v4.13 propagate_umount() takes down propagated copies of
the victim with children as long as each child is an overmount or
another copy of the victim, but propagate_mount_busy() only ever
checked copies without children or with just an overmount. A
container that moved a tree beneath its copy of a host mount lost
that tree from under its open file descriptor to a plain umount()
on the host. propagate_mount_busy() now applies the same rules,
walking each chain of copies once.
* Don't let a migrating task hide its reference from umount().
mnt_get_count() sums the per-cpu counters under mount_lock but
the mntget() and mntput() fast paths don't take it. A task that
takes a reference on a cpu the sum has already passed and drops
it after migrating to one the sum hasn't reached yet hides the
reference it held to begin with, and umount() succeeds with the
file still open. Gets and puts now live in separate per-cpu
counters and all puts are summed before all gets with a full
barrier in between, the way srcu_readers_active_idx_check() does
it. mntget() is unchanged and mntput() gains an smp_wmb().
* Check each submount for references right before unmounting it.
shrink_submounts() and mark_mounts_for_expiry() checked all their
victims up front. Unmounting the first could move a busy
overmount to where the next victim's propagated copy is looked up
and it was then unmounted without a check.
* Never expire a locked mount.
A shrinkable mount moved beneath a locked mount with
MOVE_MOUNT_BENEATH takes over the lock, and umount() of an
unlocked ancestor expired it and revealed what it covered. That
umount() now fails with EBUSY as it does for any other locked
child. A lazy umount still takes the whole tree.
- Overmounts and locked mounts:
* Unhash a dentry before detaching the mounts on it.
unlink(), rmdir() and rename() detach the mounts on the victim
but only d_delete() it once its inode is unlocked, a window that
includes an expedited RCU grace period. In between, a lookup from
a mount namespace in which the dentry is a mountpoint found it
hashed, positive and uncovered. Drop the dentry first, as
d_invalidate() already does.
* Don't reveal overmounted entries in refwalk.
A refwalk that had grabbed the dentry before the unlink never
rechecked it the way rcuwalk does with d_seq and mount_lock.
Without any artificial widening three walkers read the covered
file 27 times in a minute. step_into() now fails an unhashed
dentry marked DCACHE_CANT_MOUNT with -ESTALE and the walk is
retried.
* Keep covered mounts covered in OPEN_TREE_NAMESPACE.
Creating such a mount namespace only takes a user namespace and
the copy followed bind mount rules: no children without
AT_RECURSIVE and no unbindable mounts with it. An unprivileged
user could see what mounts covered in the source, such as the
parts of /proc and /sys that container runtimes mask. If the
caller doesn't own the source mount namespace a non-recursive
copy of a mount with something mounted below the requested
directory is now refused and a recursive copy includes unbindable
mounts, the way unshare() copies.
* Keep the lock on a mount that a propagated copy is moved beneath.
MNT_LOCKED moved to any mount that ended up beneath a locked
mount, propagated copies included. A host mount and umount on a
directory covered by a locked mount in a less privileged mount
namespace left that cover unlocked for the namespace's owner to
remove. Only mounts the caller places beneath take over the lock
now.
* Handle mount locking for automounts correctly. Which copies to
lock was decided by the mount namespace of the task that
triggered the automount. A task in a user namespace that
triggered one on a host mount through a file descriptor got the
host's own automount locked while its own copy stayed unlocked
and could have nosuid, nodev and noexec cleared. Use the owner of
the mount namespace the mount lands in.
- Use-after-free and crashes:
* Refuse an automount below a mount that is in no namespace.
The private clones overlayfs uses for its layers have the
MNT_NS_INTERNAL error pointer as their namespace, which
finish_automount() let through and count_mounts() dereferenced. A
fanotify filesystem mark on an overlayfs lower layer hands out
file descriptors on such a clone. With debugfs as the lower layer
opening "tracing" oopses with namespace_sem held for writing and
every mount operation on the system blocks from then on.
* Reset the old parent's ->overmount in mnt_change_mountpoint().
When propagate_umount() moved an overmount off a mount that a
file descriptor kept alive, MOVE_MOUNT_BENEATH through that
descriptor later followed the stale pointer into the freed
overmount.
* statmount() with STATMOUNT_BY_FD and pivot_root() read the parent
of a mount that may be unmounted and only held by a file
descriptor, while the parent's final mntput() can free it.
statmount() now reads it under mount_lock and pivot_root() first
checks that both mounts are in the caller's mount namespace.
* Queue a mount only once for mount notifications. A mount
reparented by one umount_tree() and taken down by the next under
the same namespace_sem hold, as in shrink_submounts(), was queued
twice. That cut the mounts queued in between out of notify_list
while it still pointed at them, and once they were freed every
later mount operation walked freed memory.
* Don't let a pseudo dentry become the root of a mount. A bind
mount of a bpf token file did that with a DCACHE_NORCU dentry,
which is freed without an RCU grace period while lockless path
walks may still look at it. Refuse to clone such a mount.
* Don't inherit MNT_UMOUNT in clone_mnt(). A bind mount of a lazily
unmounted nsfs or pidfs mount through its file descriptor started
out flagged as unmounted. Among other things __detach_mounts()
then dropped the namespace's reference on it, the mount outlived
its namespace and mount_setattr() through the descriptor read the
freed namespace. A recursive bind mount of such a mount also
copied the unmounted stack still attached to it. That now fails
with EINVAL, copying the mount itself still works.
* Remove the fsnotify marks of a mount namespace in free_mnt_ns()
instead of the RCU callback that frees the namespace, where
taking the group mutexes meant sleeping in softirq context.
- Propagation and copies:
* Keep a copied mount unbindable. Since v6.17 clone_mnt() didn't
copy the unbindable flag, so every mount namespace created with
CLONE_NEWNS had bindable copies of all unbindable mounts. This
had been fixed once before.
* Refuse MOVE_MOUNT_SET_GROUP on an unbindable mount. It made the
mount an unbindable slave, a state nothing else can produce, or
silently dropped the unbindable flag. CRIU applies MS_UNBINDABLE
after restoring sharing and isn't affected.
* Check a recursive bind mount for mount namespace loops.
Recursively bind mounting a tree from another mount namespace
could put a mount of a namespace's file inside that same
namespace, which then pins itself and all its mounts. Repeating
it leaks without limit, the reproducer took Shmem from 380 kB to
65916 kB. The copy is now checked with check_for_nsfs_mounts()
before it is grafted, as move_mount() does.
* Look at the topmost mount for a mount namespace file.
attach_recursive_mnt() never looked at the topmost mount of the
source's chain of overmounts. If that was the chain's only mount
namespace file an existing mount at a propagated destination got
buried below the root of the nsfs file where no path walk reaches
it.
* Don't put a mountpoint on a dentry that's being removed.
attach_recursive_mnt() makes a mountpoint of the source's root
without its inode lock, so a racing rmdir() of that directory
could leave a mount on it that nothing ever detaches.
d_set_mounted() now checks cant_mount() as well.
- nullfs:
* Take no inode lock for readdir of an immutable directory.
The root of every empty mount namespace is the same nullfs
directory and iterate_dir() held its i_rwsem across
->iterate_shared(). A reader whose buffer faults on a FUSE mount
of its own holds it for as long as its server wants, and with an
exclusive locker queued behind it every lookup that misses the
dcache, every create and every mount in that directory waits. One
user of an empty mount namespace stalls all others. Directories
with the new FOP_IMMUTABLE flag skip the lock.
* Refuse to reconfigure internal superblocks through fspick(),
MS_REMOUNT or the read-only remount that a synchronous umount()
of the root does. For nullfs only root in the initial user
namespace could do it, but the superblock is shared by every
mount namespace and the flags showed up in statfs() for all of
them.
* Don't update the access time on nullfs and refuse F_SET_RW_HINT
on an immutable inode.
- unshare: Free an nsproxy that was never installed with
nsproxy_free() when set_cred_ucounts() fails. put_nsproxy() dropped
active references that were never taken, which triggered a warning
and hid the caller's own namespaces from listns().
- Smaller changes: mount_setattr() checks the target before it walks
the tree to allocate peer group ids, unshare() puts the old
fs_struct before the old namespaces, dissolve_on_fput() drops the
file's reference to the tree itself, disconnect_mount() is
simplified and the documentation of the propagated unmount rule is
brought up to date"
* tag 'vfs-7.3-rc7.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (58 commits)
namespace: simplify disconnect_mount()
selftests/filesystems: test covered mounts
namespace: rework connected mounts
nullfs: add an empty immutable regular file
selftests/filesystems: check that reading the root of an empty mount namespace stalls nobody
selftests/filesystems: add a helper that holds a readdir in a page fault
readdir: take no inode lock on an immutable directory
nullfs: refuse file locks
fsnotify: let a filesystem refuse marks on its objects
namespace: nothing is mounted on or written through knullfs
namespace: keep the private nullfs instance in knullfs
fhandle: decide the subtree check under mount_lock
selftests/filesystems: check that an automount below an overlay layer is refused
selftests/filesystems: check the atime of the empty mount namespace root
selftests/filesystems: check that a lock lands on the right mount and stays
namespace: keep the lock on a mount that a propagated copy is moved beneath
namespace: never expire a locked mount
nullfs: don't update the access time
namespace: handle mount locking for automounts correctly
namespace: refuse an automount below a mount that is in no namespace
...
|
||
|
Dave Hansen
|
47e725702b |
mm: make per-VMA locks available universally
Patch series "mm: Unconditional per-VMA locks and cleanups", v7.
tl;dr: Make per-VMA locks available in all configs. Simplify some of the
per-VMA lock users now that they can rely on them being always available.
Binder and networking folks: Your code is the target of the cleanups. I'm
cc'ing you now on v2 because there's emerging consensus on the mm side
that the approach here is sane. I'm not quite sure how this pile would
get merged, but ack/review tags would be appreciated if this looks good to
you.
Longer version:
When working on some x86 shadow stack code, it was a real pain to avoid
causing recursive locking problems with mmap_lock. One way to avoid those
was to avoid mmap_lock and use per-VMA locks instead. They are great, but
they are not available in all configs which makes them unusable in generic
code, or if you want to completely avoid mmap_lock.
Make per-VMA locks available in all configs. Right now, they are only
available on select architectures when SMP and MMU are enabled. But all
of the primitives that per-VMA locks are built on (RCU, maple trees,
refcounts) work just fine without SMP or MMU.
The only real downside is that making VMAs a wee bit bigger on !MMU and
!SMP builds.
The upside is much cleaner code, lower complexity and less #ifdeffery.
Clean up a binder VMA locking site now that it can rely on per-VMA locks.
Building on top of universally-available per-VMA locks, introduce a new
helper. Since the new API does not require callers to have a fallback to
mmap_lock, it's much easier to use. Callers can potentially replace this
very common kernel idiom:
mmap_read_lock(mm);
vma = vma_lookup()
// fiddle with vma
mmap_read_unlock(mm);
with:
vma = vma_start_read_unlocked(mm, address);
// fiddle with vma
vma_end_read(vma);
Which avoids mmap_lock entirely in the fast path.
Use that new API for another binder site and one in the TCP code.
This patch (of 7):
The per-VMA locks have been around for several years. They've had some
bugs worked out of them and have seen quite wide use. However, they are
still only available when architectures explicitly enable them. Remove
the conditional compilation around the per-VMA locks, making them
available on all architectures and configs.
The approach up to now seemed to be to add ARCH_SUPPORTS_PER_VMA_LOCK when
the architecture started using per-VMA locks in the fault handler. But,
contrary to the naming, the Kconfig option does not really indicate
whether the architecture supports per-VMA locks or not. It is more of a
marker for whether the architecture is likely to benefit from per-VMA
locks.
To me, the most important thing side-effect of universal availability is
letting per-VMA locks be used in SMP=n configs. This lets us use
per-VMA locking in all x86 code without fallbacks.
Overall, this just generally makes the kernel simpler. Just look at the
diffstat. It also opens the door to users that want to use the per-VMA
locks in common code. Doing *that* brings additional simplifications.
The downside of this is adding some fields to vm_area_struct and
mm_struct. There are likely ways to optimize this, especially for things
like SMP=n configs. For now, do the simplest thing: use the same
implementation everywhere.
== Considerations for NOMMU config ==
NOMMU systems do not write-lock VMAs, therefore read-locking a VMA would
always succeed unless VMA is detached. Therefore for NOMMU config we make
vma_mark_attached() a NOOP, which keeps VMAs always in detached state.
This causes VMA read-locking to always fail and the caller falls back to
locking mmap_lock.
The following functions will have a different implementation in NOMMU
config:
- vma_mark_attached(), vma_mark_detached() are made NOOPs, keeping VMAs
always in a detached state and preventing assertions and refcount
underflows;
- vma_start_write(), vma_start_write_killable() are made NOOPs to avoid
warnings in __vma_start_write() due to VMAs being detached. These
functions are not used in NOMMU code but __vma_start_write() is an
exported function, therefore might be used by drivers.
- vma_assert_attached() is made NOOP because it's reachable from NOMMU
code via split_vma()->vma_iter_store_new()->vma_iter_store_overwrite();
- vma_assert_write_locked() is asserting vma->vm_mm is write-locked, as
was done before this change;
- vma_assert_locked() is asserting vma->vm_mm is locked, as was done
before this change;
The following functions work for both MMU and NOMMU configs:
- vma_lock_init() performs the same initialization as for MMU config;
- mm_lock_seqcount_init(), mm_lock_seqcount_begin(),
mm_lock_seqcount_end() are called from mmap_write_{lock|unlock} and
update mm_lock_seq correctly.
- mmap_lock_speculate_try_begin(), mmap_lock_speculate_retry() work as
is because mm_lock_seq is updated correctly;
- vma_start_read(), vma_start_read_locked() will always fail because
VMAs are always detached;
- vma_end_read() will never be called because vma_start_read() never
succeeds;
- vma_is_attached() always return false because VMAs are always
detached;
- vma_assert_detached() will never trigger because VMAs are never
attached;
- vma_start_read_locked() always return false because VMAs are always
detached;
- lock_vma_under_rcu() will be safe as the attempted read lock will bail;
Changes in the following files are not affecting NOMMU config:
task_mmu.c - not compiled when CONFIG_MMU=n;
pagewalk.c - not compiled when CONFIG_MMU=n;
userfaultfd.c - not compiled when CONFIG_MMU=n (CONFIG_USERFAULTFD depends
on CONFIG_MMU);
The following changes in the BPF code are made to keep NOMMU config
working like before:
stack_map_lock_vma() - keeps mmap_lock in NOMMU config;
bpf_iter_task_vma_new() - bails out in NOMMU config;
Link: https://lore.kernel.org/20260831203056.838265-1-surenb@google.com
Link: https://lore.kernel.org/20260831203056.838265-2-surenb@google.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Lorenzo Stoakes (ARM) <ljs@kernel.org>
Acked-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Todd Kjos <tkjos@android.com>
Cc: Christian Brauner <christian@brauner.io>
Cc: Carlos Llamas <cmllamas@google.com>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: David Ahern <dsahern@kernel.org>
Cc: Arve Hjønnevåg <arve@android.com>
|
||
|
Christian Brauner
|
296a98c1fa |
fork: release the files of a failed fork after sched_cancel_fork()
Reorder copy_process() cleanup so sched_fork() taking scx_fork_rwsem
scx_pre_fork() is safe and isn't held around exiting files. Right now, a
fork that fails while another thread closed the bpf link fd will
deadlock against its own read side. It also blocks every fork on the
system:
copy_process() holds scx_fork_rwsem for read
exit_files()
close_files()
filp_close_sync()
bpf_scx_unreg()
kthread_flush_work() waits for the disable work
scx_root_disable()
percpu_down_write(&scx_fork_rwsem)
Simply release the child's files after sched_cancel_fork() dropped the
lock. The task starts out as a copy of its parent so p->files points to
the parent's table until copy_files() replaces it. exit_files() must not
run for a fork that failed before that. Clear p->files up front so
exit_files() is a no-op for those and make copy_files() set it
explicitly for CLONE_FILES.
Reported-by: Chris Mason <mason@kernel.org>
Link: https://patch.msgid.link/20260921-work-coredump-fixes-v3-7-8e4adb1619e6@kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
|
||
|
Christian Brauner
|
5fe5e24a8f |
fs: remove unshare_files()
exec is the only caller left since commit 433967cab51e ("coredump: stop
unsharing the file descriptor table"). All it does is call unshare_fd()
with CLONE_FILES and install the copy. Kill the pointless helper and
open-code it.
No functional changes.
Link: https://patch.msgid.link/20260910-work-coredump-unlock-self-v4-4-a5c1800dc930@kernel.org
Reviewed-by: NeilBrown <neil@brown.name>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
|
||
|
Christian Brauner
|
ae6c2e72e5 |
fs: move unshare_fd() to fs/file.c
Move unshare_fd() where the rest of the descriptor table lifecycle helpers live. No functional changes. Link: https://patch.msgid.link/20260910-work-coredump-unlock-self-v4-3-a5c1800dc930@kernel.org Reviewed-by: NeilBrown <neil@brown.name> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> |
||
|
Christian Brauner
|
31116e528f |
fs: add switch_files_struct()
Add switch_files_struct() to install another table on a task. It consumes the reference to the new table and puts the old one. Convert every place that switches a descriptor table except unshare_files(). No functional changes. Link: https://patch.msgid.link/20260910-work-coredump-unlock-self-v4-2-a5c1800dc930@kernel.org Reviewed-by: NeilBrown <neil@brown.name> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> |
||
|
Christian Brauner
|
0b6f31a3c0 |
unshare: don't drop active namespace references that were never taken
Active references on the namespaces of an nsproxy are taken when the nsproxy is installed into a task in switch_task_namespaces() and copy_namespaces() and dropped again by put_nsproxy() through deactivate_nsproxy(). But ksys_unshare() calls put_nsproxy() on an nsproxy that was never installed when set_cred_ucounts() fails. The new namespaces of that nsproxy go from zero to minus one and the namespaces shared with the caller lose a reference that belongs to the nsproxy the caller keeps using: WARNING: kernel/nscommon.c:171 at __ns_ref_active_put+0x1cd/0x230 nsproxy_ns_active_put deactivate_nsproxy ksys_unshare Afterwards the namespaces the caller lives in aren't listed by listns() anymore. set_cred_ucounts() only fails when alloc_ucounts() can't allocate and it only allocates when the real uid of the caller differs from its effective uid. Commit |
||
|
Christian Brauner
|
57088a37b2 |
fs: put the old fs_struct before the old namespaces in unshare()
unshare(CLONE_NEWNS) always copies the fs_struct and copy_mnt_ns() points root and pwd of that copy into the new mount namespace. The old fs_struct pins the old root and pwd until ksys_unshare() frees it at the end and switch_task_namespaces() will already put the old mount namespace before. This causes pointless work in user namespaces because the copied mounts are locked and stay connected. Switch and free the fs_struct before switching the namespaces. The old root and pwd are wasted while their mount namespace is still alive which also keeps both puts on the mntput() fast path. setns() already does this right as it updates root and pwd before the namespaces are switched. Link: https://patch.msgid.link/20260926-work-mount-fixes-2-v1-7-f357abf3d17b@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> |
||
|
Christian Brauner
|
c7de3d02e6 |
fork: use SIG_KERNEL_ONLY_MASK for the user worker signal mask
For a user worker copy_process() blocks every signal except for SIGKILL and SIGSTOP. Use SIG_KERNEL_ONLY_MASK instead of open-coding it. No functional changes. Link: https://patch.msgid.link/20260921-work-coredump-fixes-v3-15-8e4adb1619e6@kernel.org Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> |
||
|
Christian Brauner
|
1f978881ce |
fork: don't create io threads once PF_POSTCOREDUMP is set
zap_process() skips every thread that already has PF_POSTCOREDUMP set.
Such a thread is past synchronize_group_exit(), so a coredump can't
catch it anymore. It isn't counted in core_state->threads_remaining and
it isn't sent SIGKILL.
do_exit() sets PF_POSTCOREDUMP in synchronize_group_exit() and calls
io_uring_files_cancel() right after that. The cancellation runs task
work and a create_worker_cb() that io-wq queued before the exit creates
a new io-wq worker from there. If another thread started a coredump in
the meantime that worker joins a thread-group which is already being
dumped. zap_process() never saw it so it was never counted. But when it
exits it sees signal->core_state in synchronize_group_exit() and
decrements threads_remaining like any other thread.
So the count reaches zero one thread early and the dumper leaves
coredump_wait_inactive() while a thread it counted is still running.
The task has no fatal signal pending because zap_process() deliberately
didn't send it one, and it never went through get_signal() so it doesn't
have PF_SIGNALED either.
Refuse to create an io thread when the creator has PF_POSTCOREDUMP.
That costs nothing. io_uring_files_cancel() raises IO_WQ_BIT_EXIT
before it runs any task work, so a worker created from there only ever
gets to exit again, and io_should_retry_thread() doesn't retry -EINTR.
Clearing PF_POSTCOREDUMP for the new thread in copy_process() was the
other option. It makes the worker a thread like any other, but it only
helps while the dump hasn't started. A worker born after zap_process()
has run is invisible to it whatever its flags say and still decrements
threads_remaining on the way out. Refusing to create it covers both, and
then no task is ever born with the flag, so there is nothing to clear.
Moving io_uring_files_cancel() ahead of synchronize_group_exit() closes
the same window. It runs the cancellation, and whatever that can block
on, before the thread announces itself to the dumper. A thread that
blocks there never reaches coredump_task_exit() at all, so the dumper
ends up waiting for a thread that never parks. Refusing the creation
leaves the cancellation where it is. But it's very ugly to run io_uring
work even before we did all the generic exit work.
Fixes:
|
||
|
Christian Brauner
|
e760200370 |
fork: move the coredump and exec checks into create_io_thread()
Only a PF_USER_WORKER thread returns from get_signal() after a fatal signal and can go on to create a thread. get_signal() sets PF_SIGNALED before it dumps core and before it lets a PF_USER_WORKER thread return. That flags sticks. The exec'ing thread itself is never signaled. But it doesn't need the check anyway as we moved cancellation of io_uring requests before de_thread(). create_io_thread() is the only way a signaled thread creates another one. vhost_task_create() is reached from ioctls alone. io_should_retry_thread() doesn't retry -EINTR, so io-wq callers give up the same way they did when copy_process() refused. Suggested-by: Oleg Nesterov <oleg@redhat.com> Link: https://lore.kernel.org/r/aq0VLTyxNatFmLOK@redhat.com Link: https://patch.msgid.link/20260921-work-coredump-fixes-v3-13-8e4adb1619e6@kernel.org Acked-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> |
||
|
Tim Chen
|
b636fef85b |
sched/cache: Introduce task_struct->sched_cache_grp to fix UAF
Add a sched_cache_grp pointer to task_struct so that scheduler code
can access the cache group directly via the task, without going
through mm->sched_cache_grp. This decouples the scheduler's hot-path
accesses from the mm_struct.
Each task holds its own refcount on the sched_cache_group, separate
from the reference held by its mm_struct. The reference is acquired
in copy_mm() (fork) and exec_mmap() (exec), and released in exit_mm().
This fixes the use-after-free when account_mm_sched() reaches the group
through a task whose mm is being switched, as reported by Hyunwoo:
https://lore.kernel.org/lkml/apPb-Dr4nPYuHQOK@v4bel/
Convert all scheduler code in fair.c and exit.c to use
p->sched_cache_grp instead of p->mm->sched_cache_grp.
Keep the fork/exec/exit reference management out of the generic mm
paths: add sched_cache_fork(), sched_cache_fork_cleanup(),
sched_cache_exec_mmap() and sched_cache_exit_mm() in
kernel/sched/cache_sched.c (with empty stubs for !CONFIG_SCHED_CACHE),
so fs/exec.c, kernel/fork.c and kernel/exit.c each call one helper
instead of open-coding the refcounting under #ifdef. Also add
sched_cache_group_get() and task_cache_group_get().
Fixes:
|
||
|
Peter Zijlstra
|
b61b6f95d6 |
futex: Also allocate private hash on vfork()
As Jann demonstrated, it is entirely feasible to access the mm through vfork().
Therefore we need to allocate a private hash on vfork() as well as any other
CLONE_VM user.
Specifically, it must be avoided to have (private) futex waiters before
allocating the private hash.
Fixes:
|
||
|
Jérémy Jean
|
08cacffeef |
ftrace: fork: Initialize function graph state before copy_exec_state()
dup_task_struct() copies the parent's task_struct, including ret_stack.
ftrace_graph_init_task() clears the copied function graph state, but it
currently runs after copy_exec_state().
For non-CLONE_VM forks, copy_exec_state() allocates a new task_exec_state.
If that allocation fails, copy_process() reaches bad_fork_free and
free_task() calls ftrace_graph_exit_task(). Since the child still carries
the parent's ret_stack pointer, the unwind frees the parent's active
function graph return stack. The parent subsequently accesses freed memory
from function_graph_enter_regs().
KASAN reports:
[ 22.190920] ==================================================================
[ 22.195899] BUG: KASAN: slab-use-after-free in function_graph_enter_regs+0xa76/0xb90
[ 22.200747] Write of size 8 at addr ff110000054dc0a8 by task repro/1
[ 22.205134]
[ 22.210770] CPU: 0 UID: 0 PID: 1 Comm: repro Not tainted 7.2.0-07732-g9328b3b03bdc-dirty #3 PREEMPT(lazy)
[ 22.212576] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[ 22.213750] Call Trace:
[ 22.215271] <TASK>
[ 22.216242] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.217774] dump_stack_lvl+0x4e/0x70
[ 22.220531] print_report+0x157/0x4b4
[ 22.223202] ? fixup_red_left+0x9/0x30
[ 22.224407] ? complete_report_info+0x83/0x110
[ 22.226679] ? function_graph_enter_regs+0xa76/0xb90
[ 22.228084] kasan_report+0xce/0x100
[ 22.230109] ? function_graph_enter_regs+0xa76/0xb90
[ 22.232860] ? stack_trace_save+0x4/0xd0
[ 22.234156] function_graph_enter_regs+0xa76/0xb90
[ 22.236090] ? kasan_save_stack+0x30/0x50
[ 22.237752] ? __pfx_function_graph_enter_regs+0x10/0x10
[ 22.238694] ? ring_buffer_lock_reserve+0x345/0xf80
[ 22.239628] ? stack_trace_save+0x4/0xd0
[ 22.242121] ? stack_trace_save+0x4/0xd0
[ 22.243588] ftrace_graph_func+0xda/0x160
[ 22.245362] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.246520] 0xffffffffa0000095
[ 22.250528] ? stack_trace_save+0x9/0xd0
[ 22.251757] ? ring_buffer_unlock_commit+0x11d/0x5c0
[ 22.253152] stack_trace_save+0x9/0xd0
[ 22.254264] kasan_save_stack+0x30/0x50
[ 22.273631] kasan_save_track+0x14/0x30
[ 22.276763] kasan_save_free_info+0x3b/0x70
[ 22.278296] __kasan_slab_free+0x43/0x70
[ 22.280157] kmem_cache_free+0xbf/0x3b0
[ 22.282963] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.284001] free_task+0xa2/0x160
[ 22.285699] ? ftrace_stub_direct_tramp+0x10/0x10
[ 22.286752] copy_process+0x2aae/0x7bc0
Initialize the child function graph state immediately after
dup_task_struct(), before the first fallible operation.
Cc: stable@vger.kernel.org
Fixes:
|
||
|
Linus Torvalds
|
e5f9260615 |
Merge tag 'mm-nonmm-stable-2026-08-22-16-57' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton: - "ocfs2/dlm: bound peer-controlled lengths in the o2dlm" (Bryam Vargas) Validate and bound all input lengths and count fields in the o2dlm migration and recovery receive handlers to prevent memory corruption and kernel panics from malformed cluster messages - "ocfs2: validate xattr entry bounds" (Cen Zhang) Validate OCFS2 extended attribute entry name and value bounds during metadata reads to prevent out-of-range memory accesses during retrieval or listing operations. - "taskstats: fix cgroupstats invalid fd handling and add selftests" (Yiyang Chen) Return -EBADF when cgroupstats receives an invalid file descriptor to prevent caller hangs and misleading success ACKs. Add a kselftest to validate valid cgroup v1 queries and verify proper error handling across different Netlink flag combinations. - "misc lib/raid/ improvements v2" (Christoph Hellwig) Improve benchmark-based algorithm selection for the XOR and RAID6 libraries, add KUnit benchmark tests, and cleanup minor implementation details. - "ocfs2: cluster: o2hb_region_pin() fixes" (Joseph Qi) Fix sleeping-in-atomic, lock order inversion and error-path cleanup bugs in o2hb_region_pin() by releasing o2hb_live_lock across sleeping configfs_depend_item() calls and using unlocked variants from callback context. Ensure failed pin attempts properly decrement user counts and unpin partially initialized heartbeat regions to prevent memory leaks and unprotected states. - "lib/ucs2_string.c: fix out-of-bounds read in ucs2_strnlen()" (Vincent Mailhol) Fix an off-by-one which could cause an out-of-bounds read. - "ocfs2: harden heartbeat teardown races" (Cen Zhang) Fix two OCFS2 heartbeat/o2net teardown races found by KASAN. - "taskstats: tidy up the cpumask command path" *Bradley Morgan) make two small cleanups in kernel/taskstats.c. - "ocfs2: validate active orphan slots during inode read" (ZhengYuan Huang) Validate active ordinary and append-DIO orphan slots read from OCFS2 dinodes at the metadata boundary to prevent corrupted slot indices from causing out-of-bounds array accesses. - "ocfs2: bound-check both readdir re-validation scans" (Zhan Xusheng) Enforce strict boundary checks on directory entry record lengths and offset calculations during OCFS2 directory re-scans to prevent out-of-bounds memory reads and directory position corruption. * tag 'mm-nonmm-stable-2026-08-22-16-57' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (95 commits) mailmap: fix bouncing address for Taniya Das ocfs2: bound-check dir entries in the inline-data re-validation scan ocfs2: bound-check dir entries in the readdir re-validation scan squashfs: avoid thundering-herd cache wakeups prctl: fix PR_SET_MM_AUXV losing the forced AT_NULL terminator mailmap: update email address for Linfeng Sun lib/interval_tree: fix allocation warning messages checkpatch: add NOKPROBE_SYMBOL to the whitelist of lines that can occur immediately after functions Squashfs: check block offset is not negative signal: factor out the kernel reserved si_code check ocfs2: fix readdir position truncation on 32-bit kernels ocfs2: fix cached cluster count after suballocator reclaim ocfs2: fix circular locking dependency in ocfs2_init_acl() ocfs2: validate DIO orphan slot during inode read ocfs2: validate orphan slot during inode read selftests/prctl: fix non-anonymous VMA mapping in set-anon-vma-name test MAINTAINERS: add IRC and patchwork for LTP include/linux/list.h: mark list_add and __list_add as __always_inline tools/mm: prevent page_owner_sort from truncating input hung_task: update DETECT_HUNG_TASK_BLOCKER Kconfig help ... |
||
|
Linus Torvalds
|
0d78592583 |
Merge tag 'locking-urgent-2026-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull futex fixes from Ingo Molnar: - Enforce that the private futex owner shares the mm when attaching (Kyle Zeng, Thomas Gleixner) - Fix race on the initial mm->futex.phash.ref allocation (Hyunwoo Kim) - Fix might_sleep() warning in futex_pivot_pending() (Peter Zijlstra) * tag 'locking-urgent-2026-08-22' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: futex: Fix might_sleep() warning in futex_pivot_pending() futex: Fix race on the initial mm->futex.phash.ref allocation futex: Clean up the redundant exit/exec functions futex/pi: Plug private futex exec() race futex: Sanitize and document task_struct::futex::state transitions futex/pi: Reject cross-mm private futex owners |
||
|
Linus Torvalds
|
0dd1a54f44 |
Merge tag 'smp-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull SMP core updates from Thomas Gleixner: - Reduce the preemption disabled sections in smp_call_function*(). The various smp call functions keep preemption disabled accross the full operation which includes the wait for completion. Especially the latter can take some time when one of the target CPUs is not immediately responding to the IPI, which can result in large latency spikes. To improve this provide a per task CPU mask to track the CPUs to wait for. That makes the information required for the wait task local and therefore allows to reenable preemption before the wait. While this comes with moderate extra memory cost this reduces SMP function call induced latency measured in a fleet for high priority tasks from ~17ms to ~1.5ms (~90%). - Reduce the overhead of the CSD debug code by replacing the heavy memory barriers with smp_store_release()/acquire() - Remove obsolute unused hotplug states * tag 'smp-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: scftorture: Remove preempt_disable() in scftorture_invoke_one() smp: Remove preempt_disable() from on_each_cpu_cond_mask() smp: Remove preempt_disable() from smp_call_function() smp: Enable preemption early in smp_call_function_many_cond() smp: Alloc percpu csd data in smpcfd_prepare_cpu() only once smp: Use task-local IPI cpumask in smp_call_function_many_cond() smp: Refactor remote CPU selection in smp_call_function_any() smp: Enable preemption early in smp_call_function_single() smp: Disable preemption explicitly in __csd_lock_wait() cpu/hotplug: Remove CPUHP_AP_ARM_CORESIGHT_CTI_STARTING smp: Use release stores for csd_lock_record() state |
||
|
Linus Torvalds
|
8915457146 |
Merge tag 'perf-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull performance events updates from Ingo Molnar:
"uprobes updates:
- Fix a category of bugs with optimized uprobes that can clobber the
redzone area with call instruction storing return address on stack
where user code may keep temporary data without adjusting RSP.
Fix this by moving the optimized uprobes on top of 10-bytes NOP
instruction, so we can squeeze another instruction to escape the
redzone area before doing the call (Jiri Olsa, Andrii Nakryiko)
- Switch uretprobes_srcu to SRCU-fast-updown, to improve performance
(Puranjay Mohan)
Intel CPU PMU driver updates:
- Optimize ACR handling in match_prev_assignment() (Dapeng Mi)
- Fix various PMU driver bugs and data leaks (Dapeng Mi)
- Fix Intel PT stop/start with no update (Adrian Hunter)
Intel uncore PMU driver updates:
- Fix various uncore PMU setup robustness bugs (Zide Chen)
AMD uncore PMU driver updates:
- Add group validation (Sandipan Das)
.. and misc fixes and updates by Dapeng Mi, Randy Dunlap and Zide Chen"
* tag 'perf-core-2026-08-17' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (42 commits)
perf/x86: Optimize ACR handling in match_prev_assignment()
perf/x86/intel: Fix intel_cap handling on hybrid PMUs
perf/x86: Remove stale fixed counter helper and fix hybrid PMU access
perf/x86/intel: Unwind cpuc state if PEBS buffer setup fails
perf/x86: Guard intel_pmu_cpu_dead() against invalid hybrid PMU casts
perf/x86: Free hybrid state on PMU init failure
perf/x86: Unregister PMI handler on PMU init failure
perf/x86/intel/pt: Fix stop/start with no update
perf/x86/intel/pt: Use bitwise access for PERF_HES_STOPPED
perf/x86/intel/pt: Factor out pt_config_enable()
uprobes: Switch uretprobes_srcu to SRCU-fast-updown
srcu: Add lock guard for srcu_fast_updown flavor
perf/x86/intel/pt: Drop kernel-doc for deleted struct members
perf/x86/amd/uncore: Add group validation
selftests/bpf: Add tests for forked/cloned optimized uprobes
selftests/bpf: Add tests for uprobe nop10 red zone clobbering
selftests/bpf: Add reattach tests for uprobe syscall
selftests/bpf: Change uprobe/usdt trigger bench code to use nop10
selftests/bpf: Change uprobe syscall tests to use nop10
selftests/bpf: Emit nop,nop10 instructions combo for x86_64 arch
...
|
||
|
Linus Torvalds
|
fff0150b02 |
Merge tag 'vfs-7.3-rc1.kthread' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull kthread vfs updates from Christian Brauner: "This stops kernel threads from sharing filesystem state with userspace. This work is about 3 cycles old and has been in -next for about that time. When the kernel boots init_task creates PID 1 and then kthreadd. From that point every kthread and PID 1 share the same fs_struct. That is why pivot_root() has to rewrite the fs_struct of all kthreads. The rewriting exists so that kthreads can use init's filesystem state when they want to. It also means userspace can move the ground out from under the kernel. PID 1 now gets a completely separate fs_struct. All kthreads are anchored in a private SB_KERNMOUNT instance of nullfs that cannot be mounted on and cannot be used to follow other mounts. Userspace init can no longer affect kthread filesystem state and kthreads can no longer affect userspace fs state without explicit opting in to that. Path lookup from a kthread now fails by default. It makes it deliberately hard to offload security sensitive operations into init's filesystem state from a kthread. Places that legitimately need to look something up there opt in through the new scoped_with_init_fs() which temporarily overrides the caller's fs_struct with init's. usermodehelpers remain the only kernel tasks that genuinely share init's filesystem state, since they execute random binaries in the root filesystem (excellent...). The visible result is that /proc/2/root is a nullfs with an empty mountinfo while /proc/1/root is the real root" * tag 'vfs-7.3-rc1.kthread' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (26 commits) initramfs_test: use test init/exit hooks to override init fs fs: stop rewriting paths for PF_EXITING | PF_DUMPCORE fs: stop rewriting kthread fs structs fs: start all kthreads in nullfs nullfs: make nullfs multi-instance devtmpfs: create private mount namespace fs: add umh argument to struct kernel_clone_args fs: stop sharing fs_struct between init_task and pid 1 af_unix: use scoped_with_init_fs() for coredump socket lookup initramfs: use scoped_with_init_fs() for rootfs unpacking pnfs/blocklayout: use scoped_with_init_fs() for SCSI device lookup ksmbd: use scoped_with_init_fs() for VFS path operations ksmbd: use scoped_with_init_fs() for filesystem info path lookup ksmbd: use scoped_with_init_fs() for share path resolution fs: use scoped_with_init_fs() for kernel_read_file_from_path_initns() coredump: use scoped_with_init_fs() for coredump path resolution btrfs: use scoped_with_init_fs() for update_dev_time() scsi: target: use scoped_with_init_fs() for APTPL metadata scsi: target: use scoped_with_init_fs() for ALUA metadata crypto: ccp: use scoped_with_init_fs() for SEV file access ... |
||
|
Thomas Gleixner
|
221b62e978 |
futex: Clean up the redundant exit/exec functions
futex_exit_release() and futex_exec_release() are identical now. That means also exit_mm_release() and exec_mm_release() are identical. Consolidate the whole lot and remove the redundant copies. Signed-off-by: Thomas Gleixner <tglx@kernel.org> Reviewed-by: Kyle Zeng <kylebot@openai.com> Acked-by: Peter Zijlstra <peterz@infradead.org> |
||
|
JianChunfu
|
1db1573bc5 |
kernel/fork: declare max_threads __read_mostly
max_threads is initialized once by fork_init()->set_max_threads(), and
thereafter is mostly read in hot path, such as copy_process().
The fact that it is mostly read and not written to makes it candidates for
__read_mostly declarations.
I have already tested on my machine(arm64,256core,kernel-7.1.3) with
'hackbench -P -l 500 -g 100/500/1000/2000' and the results show that there
is an average of 13% improvement in performance.
before patch:
hackbench -g 100 500 1000 2000
1.094 4.651 13.305 36.322
after patch:
hackbench -g 100 500 1000 2000
0.823 4.487 11.107 32.987
Above data are the average values obtained from multiple tests, and there
was indeed some fluctuation in the data during the tests.
Link: https://lore.kernel.org/20260707092354.465847-1-jansef.jian@hj-micro.com
Signed-off-by: JianChunfu <jansef.jian@hj-micro.com>
Reviewed-by: Lorenzo Stoakes <ljs@kernel.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
||
|
Ingo Molnar
|
f70494ac4c |
Merge branch 'perf/urgent' into perf/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org> |
||
|
Chuyi Zhou
|
9a560af15f |
smp: Use task-local IPI cpumask in smp_call_function_many_cond()
smp_call_function_many_cond() uses the per-CPU cfd->cpumask as the list of remote CPUs to wait for. That is safe while the caller remains pinned to the current CPU for the whole operation, because another task cannot run on the same CPU and reuse the per-CPU mask. The synchronous wait is the long-latency part of the operation. To make that wait preemptible, the mask iterated by csd_lock_wait() must remain stable even if the task is preempted or migrates. If the wait used the per-CPU cfd->cpumask after dropping CPU pinning, another task scheduled on the original CPU could enter smp_call_function_many_cond() and overwrite the mask while the first task is still iterating it. Give each task private IPI cpumask storage and use it as the wait mask in smp_call_function_many_cond(). Other cpumask storage choices do not fit this use case: - Per-CPU storage is the state that becomes unsafe once the wait is made preemptible. After the caller drops CPU pinning, another task scheduled on the original CPU can enter smp_call_function_many_cond() and reuse the same per-CPU mask. - Stack storage is not suitable for large NR_CPUS or CONFIG_CPUMASK_OFFSTACK=y configurations. The wait mask needs to scale with cpumask_size(), and putting that storage on the stack is not acceptable on large systems. - Allocating the mask inside smp_call_function_many_cond() would put an allocation and a failure path in the generic IPI path. A sleeping allocation is not suitable because callers have historically only provided a preempt-disabled context, not a sleepable one. GFP_ATOMIC would avoid sleeping, but a failure fallback would make the latency improvement opportunistic instead of guaranteed. The users are not limited to a small, pre-identifiable class of tasks. On x86, ordinary tasks can reach this path through TLB flushes during exit, unmap and reclaim, so allocating the mask only for a known subset of tasks is not straightforward. The memory cost is explicit: one word is added to task_struct. When cpumask_size() fits in that word, the mask is stored inline and no separate allocation is needed. Larger systems allocate cpumask_size() per task; on x86-64 NR_CPUS=8192 this is 1 KiB per task. For context, x86 already carries several KiB of per-task architecture and FPU state, depending on the enabled features and configuration. That does not make the extra cpumask free, but it puts the large-NR_CPUS case in perspective. Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Tested-by: Paul E. McKenney <paulmck@kernel.org> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://patch.msgid.link/20260709122933.4021501-5-zhouchuyi@bytedance.com |
||
|
Jiri Olsa
|
38af0dd6a2 |
uprobes/x86: Remove struct uprobe_trampoline object
Removing struct uprobe_trampoline object and it's tracking code, because it's not needed. We can do same thing directly on top of struct vm_area_struct objects. This makes the code simpler and allows easy propagation of the trampoline vma object into child process in following change. Note the original code called destroy_uprobe_trampoline if the optimiation failed, but it only freed the struct uprobe_trampoline object, not the vma. The new vma leak is fixed in following change. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Link: https://patch.msgid.link/20260703114917.238144-3-jolsa@kernel.org |
||
|
Jann Horn
|
9b51a6155d |
bpf,fork: wipe ->bpf_storage before bailouts that access it
Currently, copy_process() can bail out to free_task() before p->bpf_storage
has been initialized, with this call graph (shown here for the
!CONFIG_MEMCG case):
copy_process
dup_task_struct
arch_dup_task_struct
[copies the entire task_struct, including ->bpf_storage member]
[RLIMIT_NPROC check fails]
delayed_free_task
free_task
bpf_task_storage_free
rcu_dereference(task->bpf_storage)
bpf_local_storage_destroy
In this case, the nascent task's ->bpf_storage member that
bpf_local_storage_destroy() operates on is a plain copy of the parent's
->bpf_storage pointer, not a real initialized pointer.
This leads to badness (kernel hangs, UAF).
This is reachable as long as the process calling fork() has been inserted
into a task storage map.
Cc: stable@kernel.org
Fixes:
|
||
|
Christian Brauner
|
ed4b167252 |
fs: add umh argument to struct kernel_clone_args
Add a umh field to struct kernel_clone_args. When set, copy_fs() copies from pid 1's fs_struct instead of the kthread's fs_struct. This ensures usermodehelper threads always get init's filesystem state regardless of their parent's (kthreadd's) fs. Usermodehelper threads are not allowed to create mount namespaces (CLONE_NEWNS), share filesystem state (CLONE_FS), or be started from a non-initial mount namespace. No usermodehelper currently does this so we don't need to worry about this restriction. Set .umh = 1 in user_mode_thread(). At this stage pid 1's fs points to rootfs which is the same as kthreadd's fs, so this is functionally equivalent. Link: https://patch.msgid.link/20260601-work-kthread-nullfs-v4-20-77ee053060e0@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> |
||
|
Christian Brauner
|
1d4ee94a51 |
fs: add real_fs to track task's actual fs_struct
Add a real_fs field to task_struct that always mirrors the fs field. This lays the groundwork for distinguishing between a task's permanent fs_struct and one that is temporarily overridden via scoped_with_init_fs(). When a kthread temporarily overrides current->fs for path lookup, we need to know the original fs_struct for operations like exit_fs() and unshare_fs_struct() that must operate on the real, permanent fs. For now real_fs is always equal to fs. It is maintained alongside fs in all the relevant paths: exit_fs(), unshare_fs_struct(), switch_fs_struct(), and copy_fs(). Link: https://patch.msgid.link/20260601-work-kthread-nullfs-v4-4-77ee053060e0@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> |
||
|
Christian Brauner
|
21bcea3ef2 |
fs: add switch_fs_struct()
Don't open-code the guts of replacing current's fs struct. Link: https://patch.msgid.link/20260601-work-kthread-nullfs-v4-1-77ee053060e0@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> |
||
|
Linus Torvalds
|
a142da0b2d |
Merge tag 'block-7.2-20260625' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux
Pull block fixes from Jens Axboe:
- blk-cgroup locking rework and fixes:
- fix a use-after-free in __blkcg_rstat_flush()
- defer freeing policy data until after an RCU grace period
- defer the blkcg css_put until the blkg is unlinked from
the queue
- unwind the queue_lock nesting under RCU / blkcg->lock
across the lookup, create, associate and destroy paths
- NVMe fixes via Keith:
- Fix a crash and memory leak during invalid cdev teardown,
and related cdev cleanups (Maurizio, John)
- nvmet fixes: handle TCP_CLOSING in the tcp state_change
handler, reject short AUTH_RECEIVE buffers, handle inline
data with a nonzero offset in rdma, fix an sq refcount leak,
and allocate ana_state with the port (Maurizio, Michael,
Bryam, Wentao, Rosen)
- nvme-fc fix to not cancel requests on an IO target before it
is initialized (Mohamed)
- nvme-apple fix to prevent shared tags across queues on Apple
A11 (Nick)
- Various smaller fixes and cleanups (John)
- MD fixes via Yu Kuai:
- raid1/raid10 fixes for writes_pending and barrier reference
leaks on write and discard failures, plus REQ_NOWAIT handling
fixes (Abd-Alrhman)
- raid5 discard accounting and validation, and a batch of fixes
for stripe batch races (Yu Kuai, Chen)
- Protect raid1 head_position during read balancing (Chen)
- block bio-integrity fixes: correct an error injection static key
decrement, fix GFP flag confusion in bio_integrity_alloc_buf(), and
handle REQ_OP_ZONE_APPEND in __bio_integrity_action() (Christoph)
- Fixes for bio_iov_iter_bounce_write(): revert the iov_iter after a
short copy, and respect the iov_iter nofault flag (Qu)
- Invalidate the cached plug timestamp after a task switch, and clear
PF_BLOCK_TS in copy_process() (Usama)
- Fix the IORING_URING_CMD_REISSUE flags check in blkdev_uring_cmd()
(Yitang)
- Remove a redundant plug in __submit_bio() (Wen)
- Don't warn when reclassifying a busy socket lock in nbd (Deepanshu)
* tag 'block-7.2-20260625' of git://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux: (45 commits)
block: handle REQ_OP_ZONE_APPEND in __bio_integrity_action
block: fix GFP_ flags confusion in bio_integrity_alloc_buf
block, bfq: don't grab queue_lock to initialize bfq
mm/page_io: don't nest queue_lock under rcu in bio_associate_blkg_from_page()
blk-cgroup: don't nest queue_lock under blkcg->lock in blkcg_destroy_blkgs()
blk-cgroup: don't nest queue_lock under rcu in bio_associate_blkg()
blk-cgroup: don't nest queue_lock under rcu in blkg_lookup_create()
blk-cgroup: don't nest queue_lock under rcu in blkcg_print_blkgs()
blk-cgroup: delay freeing policy data after rcu grace period
blk-cgroup: protect iterating blkgs with blkcg->lock in blkcg_print_stat()
md/raid5: avoid R5_Overlap races while breaking stripe batches
md/raid5: use stripe state snapshot in break_stripe_batch_list()
blk-cgroup: defer blkcg css_put until blkg is unlinked from queue
blk-cgroup: fix UAF in __blkcg_rstat_flush()
block, bfq: protect async queue reset with blkcg locks
nbd: don't warn when reclassifying a busy socket lock
block: fix incorrect error injection static key decrement
md/raid5: let stripe batch bm_seq comparison wrap-safe
md/raid1: protect head_position for read balance
md/raid1: free r1_bio when REQ_NOWAIT is set and read would block on retry
...
|
||
|
Linus Torvalds
|
a552c81ff4 |
Merge tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull MM updates from Andrew Morton:
- "selftests/mm: clean up build output and verbosity" (Li Wang)
Remove some noise from the MM selftests build
- "mm: Free contiguous order-0 pages efficiently" (Ryan Roberts)
Speed up the freeing of a batch of 0-order pages by first scanning
them for coalescing opportunities. This is applicable to vfree() and
to the releasing of frozen pages
- "mm/damon: introduce DAMOS failed region quota charge ratio"
(SeongJae Park)
Address a DAMOS usability issue: The DAMOS quota often exhausts
prematurely because it charges for all memory attempted, causing slow
and inconsistent performance when actions fail on unreclaimable
memory.
To fix this, a new feature lets users set a smaller, flexible quota
charge ratio (via a numerator and denominator) for failed regions.
Since failed actions cause less overhead, reducing their quota cost
ensures more predictable and efficient DAMOS processing
- "selftests/cgroup: improve zswap tests robustness and support large
page sizes" (Li Wang)
Fix various spurious failures and improves the overall robustness of
the cgroup zswap selftests
- "fix MAP_DROPPABLE not supported errno" (Anthony Yznaga)
Fix an issue in the mlock selftests on arm32
- "mm: huge_memory: clean up defrag sysfs with shared" (Breno Leitao)
Some maintenance work in the huge_memory code
- "treewide: fixup gfp_t printks" (Brendan Jackman)
Use the special vprintf() gfp_t conversion in various places
- "mm: Fix vmemmap optimization accounting and initialization" (Muchun
Song)
Fix several bugs in the vmemmap optimization, mainly around incorrect
page accounting and memmap initialization in the DAX and memory
hotplug paths. It also fixes pageblock migratetype initialization and
struct page initialization for ZONE_DEVICE compound pages
- "mm/damon: repost non-hotfix reviewed patches in damon/next tree"
A sprinkle of unrelated minor bugfixes for DAMON
- "mm: remove page_mapped()" (David Hildenbrand)
Remove this function from the tree, replacing it with folio_mapped()
- "mm/damon: let DAMON be paused and resumed" (SeongJae Park)
Allow DAMON to be paused and resumed without losing its current state
- "kasan: hw_tags: Disable tagging for stack and page-tables" (Muhammad
Usama Anjum)
Simplify and speed up kasan by removing its ineffective tagging of
stacks and page tables
- "mm/damon/reclaim,lru_sort: monitor all system rams by default"
(SeongJae Park)
Simplify deployment on diverse hardware like NUMA systems by updating
DAMON_RECLAIM and DAMON_LRU_SORT to automatically monitor the
physical address range covering all System RAM areas by default,
replacing the overly restrictive behavior that only targeted the
single largest memory block to save on negligible overhead
- "mm/damon/sysfs: document filters/ directory as deprecated" (SeongJae
Park)
Update some DAMON docs
- "mm: use spinlock guards for zone lock" (Dmitry Ilvokhin)
Switch zone->lock handling over to using the guard() mechanisms
- "mm/filemap: tighten mmap_miss hit accounting" (fujunjie)
Fix a flaw where the mmap_miss counter over-credited page cache hits
during fault-arounds and page-fault retries. This results in
significant reduction of redundant synchronous mmap readahead I/O,
drastically cutting down execution time and gigabytes read for sparse
random or strided memory access workloads
- "selftests/cgroup: Fix false positive failures in test_percpu_basic"
(Li Wang)
Fix a couple of false-positives in the cgroup kmem selftests
- "mm/damon/reclaim: support monitoring intervals auto-tuning"
(SeongJae Park)
Add a new parameter to DAMON permitting DAMON_RECLAIM to
automatically tune DAMON's sampling and aggregation intervals
- "mm/damon/stat: add kdamond_pid parameter" (SeongJae Park)
Change DAMON_STAT to provide the pid of its kdamond
- "mm/kmemleak: dedupe verbose scan output" (Breno Leitao)
Remove large amounts of duplicated backtraces from the verbose-mode
kmemleak output
- "mm: remove CONFIG_HAVE_BOOTMEM_INFO_NODE (Part 1)" (David
Hildenbrand)
Reduce our use of CONFIG_HAVE_BOOTMEM_INFO_NODE, with a view to
removing it entirely in a later series
- "mm/damon: validate min_region_size to be power of 2" (Liew Rui Yan)
Prevent users from passing a non-power-of-2 value of `addr_unit', as
this later results in undesirable behavior
- "mm: document read_pages and simplify usage" (Frederick Mayle)
- "tools/mm/page-types: Fix misc bugs" (Ye Liu)
Fix three issues in tools/mm/page-types.c
- "mm: misc cleanups from __GFP_UNMAPPED series" (Brendan Jackman)
Implement several cleanups in the page allocator and related code
- "mm, swap: swap table phase IV: unify allocation" (Kairui Song)
Unify the allocation and charging of anon and shmem swap in folios,
provides better synchronization, consolidates the metadata
management, hence dropping the static array and map, and improves
performance
- "mm/damon: introduce data attributes monitoring" (SeongJae Park(
Extend DAMON to monitor general data attributes other than accesses
- "mm/vmalloc: free unused pages on vrealloc() shrink" (Shivam Kalra)
Implement the TODO in vrealloc() to unmap and free unused pages when
shrinking across a page boundary
- "mm/damon: documentation and comment fixes" (niecheng)
- "remove mmap_action success, error hooks" (Lorenzo Stoakes)
Eliminate custom hooks from mmap_action by removing the problematic
success_hook which allowed drivers to improperly access uninitialized
VMAs. It replaces the error_hook with a simple error-code field and
updates the memory char driver accordingly
- "mm/damon: minor improvements for code readability and tests"
(SeongJae Park)
- "mm/damon: fix macro arguments and clarify quota goals doc" (Maksym
Shcherba)
- "userfaultfd: merge fs/userfaultfd.c into mm/userfaultfd.c" (Mike
Rapoport)
- "mm/mglru: improve reclaim loop and dirty folio" (Kairui Song and
others)
Clean up and slightly improves MGLRU's reclaim loop and dirty
writeback handling. Large performance improvements are measured
- "use vma locks for proc/pid/{smaps|numa_maps} reads" (Suren
Baghdasaryan)
Use per-vma locks when reading /proc/pid/smaps and numa_maps similar
to reduce contention on central mmap_lock
- "refactors thpsize_shmem_enabled_store() and thpsize_shmem_enabled_show()"
(Ran Xiaokai)
Some cleanup work in the THP code
- "selftests/memfd: fix compilation warnings" (Konstantin Khorenko)
Fix a few build glitches in the memfd selftest code.
- "memcg: shrink obj_stock_pcp and cache multiple objcgs" (Shakeel
Butt)
Resolve a 68% performance regression caused by NUMA-node cache
thrashing around struct obj_stock_pcp by shrinking its existing
fields and expanding it into a multi-slot array that caches up to
five obj_cgroup pointers per CPU, allowing per-node variants of the
same memcg to coexist within a single 64-byte cache line.
- "zram: writeback fixes" (Sergey Senozhatsky)
address a couple of unrelated zram writeback issues
- "mm: switch THP shrinker to list_lru" (Johannes Weiner)
Resolve NUMA-awareness issues and streamlines callsite interaction by
refactoring and extending the list_lru API to completely replace the
complex, open-coded deferred split queue for Transparent Huge Pages
- "mm: improve large folio readahead for exec memory" (Usama Arif)
Improve large-folio readahead on systems like 64K-page arm64 by
preventing the mmap_miss check from permanently disabling
target-oriented VM_EXEC readahead, and by generalizing the
force_thp_readahead gate to support mappings with any usefully large
maximum folio order under the cache cap.
- "userfaultfd/pagemap: pre-existing fixes" (Kiryl Shutsemau)
Fix a bunch of minor issues in the userfaultfd/pagemap, all of which
were flagged by Sashiko review of proposed new material
- "mm/sparse-vmemmap: Provide generic vmemmap_set_pmd() and
vmemmap_check_pmd()" (Muchun Song)
Provide generic versions of these two functions so the four
arch-specific implementations can be removed.
- "mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap
device" (Youngjun Park)
Address a uswsusp-vs-swapoff race and reduces the swap device
reference taking/releasing frequency.
- "mm/hmm: A fix and a selftest" (Dev Jain)
* tag 'mm-stable-2026-06-18-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (321 commits)
selftests/mm/hmm-tests: test pagemap reads of PMD device-private entries
fs/proc/task_mmu: do not warn on seeing non-migration pmd entry
lib/test_hmm: check alloc_page_vma() return value and handle OOM
mm/compaction: cap compact_gap() at COMPACT_CLUSTER_MAX
mm/swap: remove redundant swap device reference in alloc/free
mm/swap, PM: hibernate: fix swapoff race in uswsusp by pinning swap device
mm/filemap: use folio_next_index() for start
vmalloc: fix NULL pointer dereference in is_vm_area_hugepages()
sparc/mm: drop vmemmap_check_pmd helper and use generic code
loongarch/mm: drop vmemmap_check_pmd helper and use generic code
riscv/mm: drop vmemmap_pmd helpers and use generic code
arm64/mm: drop vmemmap_pmd helpers and use generic code
mm/sparse-vmemmap: provide generic vmemmap_set_pmd() and vmemmap_check_pmd()
rust: page: mark Page::nid as inline
userfaultfd: build __VMA_UFFD_FLAGS from config-gated masks
userfaultfd: gate must_wait writability check on pte_present()
mm/huge_memory: preserve pmd_swp_uffd_wp on device-private PMD downgrade
fs/proc/task_mmu: fix hugetlb self-deadlock in pagemap_scan_pte_hole()
fs/proc/task_mmu: use huge_page_size() in pagemap_scan_hugetlb_entry()
fs/proc/task_mmu: fix make_uffd_wp_huge_pte() prot-update race
...
|
||
|
Usama Arif
|
fd38b75c4b |
kernel/fork: clear PF_BLOCK_TS in copy_process()
PF_BLOCK_TS is only set in blk_time_get_ns() when current->plug is
non-NULL, and blk_finish_plug() clears it via __blk_flush_plug()
before NULLing the plug pointer. copy_process() breaks the
invariant by inheriting PF_BLOCK_TS from the parent while resetting
the child's plug to NULL.
Clear PF_BLOCK_TS alongside that assignment so callers can rely on
"PF_BLOCK_TS set implies current->plug != NULL" and dereference
current->plug unguarded.
Fixes:
|
||
|
Linus Torvalds
|
2cbf335f8c |
Merge tag 'sched-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip
Pull scheduler updates from Ingo Molnar:
"SMP load-balancing updates:
- A large series to introduce infrastructure for cache-aware load
balancing, with the goal of co-locating tasks that share data
within the same Last Level Cache (LLC) domain. By improving cache
locality, the scheduler can reduce cache bouncing and cache misses,
ultimately improving data access efficiency.
Implemented by Chen Yu and Tim Chen, based on early prototype work
by Peter Zijlstra, with fixes by Jianyong Wu, Peter Zijlstra and
Shrikanth Hegde.
- A series to simplify CONFIG_SCHED_SMT ifdef usage (Shrikanth Hegde)
Fair scheduler updates:
- A series to improve SD_ASYM_CPUCAPACITY scheduling by introducing
SMT awareness (Andrea Righi, K Prateek Nayak)
- A series to optimize cfs_rq and sched_entity allocation for better
data locality (Zecheng Li)
- A preparatory series to change fair/cgroup scheduling to a single
runqueue, without the final change (Peter Zijlstra)
- Auto-manage ext/fair dl_server bandwidth (Andrea Righi)
- Fix cpu_util runnable_avg arithmetic (Hongyan Xia)
- Optimize update_tg_load_avg()'s rate-limiting code (Rik van Riel)
- Allow account_cfs_rq_runtime() to throttle current hierarchy
(K Prateek Nayak)
- Update util_est after updating util_avg during dequeue, to fix the
util signal update logic, which reduces signal noise (Vincent
Guittot)
Scheduler topology updates:
- Allow multiple domains to claim sched_domain_shared (K Prateek
Nayak)
- Add parameter to split LLC (Peter Zijlstra)
Core scheduler updates:
- Use trace_call__<tp>() to save a static branch (Gabriele Monaco)
Scheduler statistics updates:
- Drop now-stale mul_u64_u64_div_u64() cputime over-approximation
guard (Nicolas Pitre)
Deadline scheduler updates:
- Reject debugfs dl_server writes for offline CPUs (Andrea Righi)
- Fix replenishment logic for non-deferred servers (Yuri Andriaccio)
RT scheduling updates:
- Turn RT_PUSH_IPI default off for non PREEMPT_RT (Steven Rostedt)
- Update default bandwidth for real-time tasks to 1.0 (Yuri
Andriaccio)
Proxy scheduling updates:
- A series to implement Optimized Donor Migration for Proxy Execution
(John Stultz, Peter Zijlstra)
- Various proxy scheduling cleanups and fixes (Peter Zijlstra,
K Prateek Nayak)
Misc fixes, improvements and cleanups by Aaron Lu, Andrea Righi,
Zenghui Yu, Chen Yu, Guanyou.Chen, John Stultz, Shrikanth Hegde,
Peter Zijlstra, Liang Luo and Yiyang Chen"
* tag 'sched-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (91 commits)
sched/fair: Fix newidle vs core-sched
sched/deadline: Use task_on_rq_migrating() helper
sched/core: Combine separate 'else' and 'if' statements
sched/fair: Fix cpu_util runnable_avg arithmetic
sched/fair: Unify cfs_rq throttling via account_cfs_rq_runtime()
sched/fair: Move the throttled tasks to a local list in tg_unthrottle_up()
sched/fair: Call update_curr() before unthrottling the hierarchy
sched/fair: Use throttled_csd_list for local unthrottle
sched/fair: Convert cfs bandwidth throttling to use guards
sched/fair: Allocate cfs_tg_state with percpu allocator
sched/fair: Remove task_group->se pointer array
sched/fair: Co-locate cfs_rq and sched_entity in cfs_tg_state
sched: restore timer_slack_ns when resetting RT policy on fork
MAINTAINERS: Fix spelling mistake in Peter's name
sched: Simplify ttwu_runnable()
sched/proxy: Remove superfluous clear_task_blocked_in()
sched/proxy: Remove PROXY_WAKING
sched/proxy: Switch proxy to use p->is_blocked
sched/proxy: Only return migrate when needed
sched: Be more strict about p->is_blocked
...
|
||
|
Linus Torvalds
|
764e77d868 |
Merge tag 'locking-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"Futex updates:
- Optimize futex hash bucket access patterns (Peter Zijlstra)
- Large series to address the robust futex unlock race for real, by
Thomas Gleixner:
"The robust futex unlock mechanism is racy in respect to the
clearing of the robust_list_head::list_op_pending pointer because
unlock and clearing the pointer are not atomic.
The race window is between the unlock and clearing the pending op
pointer. If the task is forced to exit in this window, exit will
access a potentially invalid pending op pointer when cleaning up
the robust list.
That happens if another task manages to unmap the object
containing the lock before the cleanup, which results in an UAF.
In the worst case this UAF can lead to memory corruption when
unrelated content has been mapped to the same address by the time
the access happens.
User space can't solve this problem without help from the kernel.
This series provides the kernel side infrastructure to help it
along:
1) Combined unlock, pointer clearing, wake-up for the
contended case
2) VDSO based unlock and pointer clearing helpers with a
fix-up function in the kernel when user space was interrupted
within the critical section.
... with help by André Almeida:
- Add a note about robust list race condition (André Almeida)
- Add self-tests for robust release operations (André Almeida)
Context analysis updates:
- Implement context analysis for 'struct rt_mutex'. (Bart Van Assche)
- Bump required Clang version to 23 (Marco Elver)
Guard infrastructure updates:
- Series to remove NULL check from unconditional guards (Dmitry
Ilvokhin)
Lockdep updates:
- Restore self-test migrate_disable() and sched_rt_mutex state on
PREEMPT_RT (Karl Mehltretter)
Membarriers updates:
- Use per-CPU mutexes for targeted commands (Aniket Gattani)
- Modernize membarrier_global_expedited with cleanup guards (Aniket
Gattani)
- Add rseq stress test for CFS throttle interactions (Aniket Gattani)
percpu-rwsems updates:
- Extract __percpu_up_read() to optimize inlining overhead (Dmitry
Ilvokhin)
Seqlocks updates:
- Allow UBSAN_ALIGNMENT to fail optimizing (Heiko Carstens)
Lock tracing:
- Add contended_release tracepoint to sleepable locks such as
mutexes, percpu-rwsems, rtmutexes, rwsems and semaphores (Dmitry
Ilvokhin)
MAINTAINERS updates:
- MAINTAINERS: Add RUST [SYNC] entry (Boqun Feng)
Misc updates and fixes by Randy Dunlap, YE WEI-HONG, Fabricio Parra,
Dmitry Ilvokhin and Peter Zijlstra"
* tag 'locking-core-2026-06-14' of gitolite.kernel.org:pub/scm/linux/kernel/git/tip/tip: (36 commits)
locking: Add contended_release tracepoint to sleepable locks
locking/percpu-rwsem: Extract __percpu_up_read()
tracing/lock: Remove unnecessary linux/sched.h include
futex: Optimize futex hash bucket access patterns
rust: sync: completion: Mark inline complete_all and wait_for_completion
MAINTAINERS: Add RUST [SYNC] entry
cleanup: Specify nonnull argument index
selftests: futex: Add tests for robust release operations
Documentation: futex: Add a note about robust list race condition
x86/vdso: Implement __vdso_futex_robust_try_unlock()
x86/vdso: Prepare for robust futex unlock support
futex: Provide infrastructure to plug the non contended robust futex unlock race
futex: Add robust futex unlock IP range
futex: Add support for unlocking robust futexes
futex: Cleanup UAPI defines
x86: Select ARCH_MEMORY_ORDER_TSO
uaccess: Provide unsafe_atomic_store_release_user()
futex: Provide UABI defines for robust list entry modifiers
futex: Move futex related mm_struct data into a struct
futex: Make futex_mm_init() void
...
|
||
|
Linus Torvalds
|
9c9e6bd4cc |
Merge tag 'kernel-7.2-rc1.task_exec_state' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull task_exec_state updates from Christian Brauner:
"This introduces a new per-task task_exec_state structure and relocates
the dumpable mode and the user namespace captured at execve() from
mm_struct onto it. It stays attached to the task for its full
lifetime.
__ptrace_may_access() and several /proc owner and visibility checks
need to consult two pieces of state for any observable task, including
zombies that have already gone through exit_mm(): the dumpable mode
and the user namespace captured at execve(). Both live on mm_struct
today, which exit_mm() clears from the task long before the task is
reaped. A reader that races with do_exit() observes task->mm == NULL
and either fails the check or falls back to init_user_ns - which
denies legitimate access to non-dumpable zombies that were running in
a nested user namespace.
mm_struct loses ->user_ns and the dumpability bits in ->flags.
MMF_DUMPABLE_BITS is reserved so the MMF_DUMP_FILTER_* layout exposed
via /proc/<pid>/coredump_filter stays stable. task->user_dumpable and
its exit_mm() snapshot are removed.
task_exec_state is the privilege domain established by an execve().
Within a thread group it is shared via refcount; across thread groups
each task has its own:
- CLONE_VM siblings (thread-group members, io_uring workers)
refcount-share the parent's exec_state.
- Non-CLONE_VM clones (fork(), vfork() without CLONE_VM) allocate a
fresh exec_state inheriting the parent's dumpable mode and user_ns.
- execve() in the child allocates a fresh instance and installs it
under task_lock + exec_update_lock via task_exec_state_replace().
- Credential changes (setresuid, capset, ...) and
prctl(PR_SET_DUMPABLE) update dumpability on the current task's
exec_state, i.e., on the thread group's shared instance.
On top of this exec_mmap() no longer tears down the old mm while
holding exec_update_lock for writing and cred_guard_mutex. Neither
lock is needed for that: exec_update_lock only exists to make the mm
swap atomic with the later commit_creds() and all its readers operate
on the new mm; none looks at the detached old mm.
The cost was real: __mmput() runs exit_mmap() over the entire old
address space and can block in exit_aio() waiting for in-flight AIO,
so execve() of a large process blocked ptrace_attach() and every
exec_update_lock reader for the duration of the teardown.
The old mm is now stashed in bprm->old_mm and released from
setup_new_exec() after both locks are dropped, with a backstop in
free_bprm() for the error paths"
* tag 'kernel-7.2-rc1.task_exec_state' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
exec: free the old mm outside the exec locks
exec_state: relocate dumpable information
ptrace: add ptracer_access_allowed()
exec: introduce struct task_exec_state
sched/coredump: introduce enum task_dumpable
|
||
|
Thomas Gleixner
|
d7b3f52c86 |
futex: Make futex_mm_init() void
Nothing fails there. Mop up the leftovers of the early version of this, which did an allocation. While at it clean up the stubs and the #ifdef comments to make the header file readable. Signed-off-by: Thomas Gleixner <tglx@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260602090535.356789395@kernel.org |
||
|
Peter Zijlstra
|
1628b25248 |
sched: Add blocked_donor link to task for smarter mutex handoffs
Add link to the task this task is proxying for, and use it so the mutex owner can do an intelligent hand-off of the mutex to the task that the owner is running on behalf. [jstultz: This patch was split out from larger proxy patch] Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Connor O'Brien <connoro@google.com> Signed-off-by: John Stultz <jstultz@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://patch.msgid.link/20260512025635.2840817-8-jstultz@google.com |
||
|
Muhammad Usama Anjum
|
6ae51adb08 |
kasan: skip HW tagging for all kernel thread stacks
HW-tag KASAN never checks kernel stacks because stack pointers carry the match-all tag, so setting/poisoning tags is pure overhead. - Add __GFP_SKIP_KASAN to THREADINFO_GFP so every stack allocator that uses it skips tagging (fork path plus arch users) - Add __GFP_SKIP_KASAN to GFP_VMAP_STACK for the fork-specific vmap stacks. - When reusing cached vmap stacks, skip kasan_unpoison_range() if HW tags are enabled. Software KASAN is unchanged; this only affects tag-based KASAN. Link: https://lore.kernel.org/20260429102704.680174-3-dev.jain@arm.com Signed-off-by: Muhammad Usama Anjum <usama.anjum@arm.com> Signed-off-by: Dev Jain <dev.jain@arm.com> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Ben Segall <bsegall@google.com> Cc: David Hildenbrand (Arm) <david@kernel.org> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Kees Cook <kees@kernel.org> Cc: K Prateek Nayak <kprateek.nayak@amd.com> Cc: Liam Howlett <liam@infradead.org> Cc: Lorenzo Stoakes <ljs@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Rapoport <rppt@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Suren Baghdasaryan <surenb@google.com> Cc: "Uladzislau Rezki (Sony)" <urezki@gmail.com> Cc: Valentin Schneider <vschneid@redhat.com> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: Vlastimil Babka <vbabka@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> |
||
|
Christian Brauner (Amutable)
|
6b1c66c9cc |
exec_state: relocate dumpable information
The dumpable flag captured at execve() is consulted by __ptrace_may_access() and several /proc owner / visibility checks. It lives on mm_struct today, which exit_mm() clears from the task long before the task itself is reaped. exec_state is anchored to the execve() that established the current privilege domain. CLONE_VM siblings refcount-share the parent's exec_state via copy_exec_state(); non-CLONE_VM clones allocate a fresh exec_state inheriting the parent's dumpable mode and user_ns reference via task_exec_state_copy(). execve() allocates a fresh instance (via alloc_task_exec_state() in begin_new_exec()) and installs it under task_lock + exec_update_lock with task_exec_state_replace(). init_task uses a static instance. The dumpable mode now lives on task->exec_state->dumpable. task->mm->flags no longer carries dumpability; MMF_DUMPABLE_MASK is removed, but MMF_DUMPABLE_BITS is reserved so MMF_DUMP_FILTER_* bit positions remain stable for the /proc/<pid>/coredump_filter ABI. The task->user_dumpable cache bit and its assignment in exit_mm() are removed; readers go through get_dumpable(task) directly. coredump_params gains a snapshot field cprm.dumpable, populated from get_dumpable(current) at vfs_coredump() entry, replacing the previous __get_dumpable(cprm->mm_flags) consumers in fs/coredump.c and fs/pidfs.c. The user namespace recorded at execve() is consulted by __ptrace_may_access() and by /proc/PID/* owner derivation. Move the captured user_ns onto task_exec_state, which stays attached to the task past exit_mm() and across exit_files(). bprm grows a user_ns field staged in bprm_mm_init() with the caller's user_ns, narrowed by would_dump() to the closest privileged ancestor, and consumed by exec_mmap() via alloc_task_exec_state(bprm->user_ns). free_bprm() releases the staging reference. mm_struct loses ->user_ns entirely. Initializers in init-mm, efi_mm, and the implicit one in mm_init()/dup_mm()/mm_alloc() are removed; __mmdrop() drops the matching put_user_ns(). The kthread_use_mm() WARN_ON_ONCE(!mm->user_ns) is no longer meaningful and goes too. Reviewed-by: Jann Horn <jannh@google.com> Link: https://patch.msgid.link/20260520-work-task_exec_state-v3-4-69f895bc1385@kernel.org Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org> |
||
|
Deepanshu Kartikey
|
09e7827e78 |
kernel/fork: validate exit_signal in kernel_clone()
When a child process exits, it sends exit_signal to its parent via
do_notify_parent(). The clone() syscall constructs exit_signal as:
(lower_32_bits(clone_flags) & CSIGNAL)
CSIGNAL is 0xff, so values in the range 65-255 are possible. However,
valid_signal() only accepts signals up to _NSIG (64 on x86_64). A
non-zero non-valid exit_signal acts the same as exit_signal == 0: the
parent process is not signaled when the child terminates.
The syzkaller reproducer triggers this by calling clone() with flags=0x80,
resulting in exit_signal = (0x80 & CSIGNAL) = 128, which exceeds _NSIG and
is not a valid signal.
The v1 of this patch added the check only in the clone() syscall handler,
which is incomplete. kernel_clone() has other callers such as
sys_ia32_clone() which would remain unprotected. Move the check to
kernel_clone() to cover all callers.
Since the valid_signal() check is now in kernel_clone() and covers all
callers including clone3(), the same check in copy_clone_args_from_user()
becomes redundant and is removed. The higher 32bits check for clone3() is
kept as it is clone3() specific.
Note that this is a user-visible change: previously, passing an invalid
exit_signal to clone() was silently accepted. The man page for clone()
does not document any defined behavior for invalid exit_signal values, so
rejecting them with -EINVAL is the correct behavior. It is unlikely that
any sane application relies on passing an invalid exit_signal.
[oleg@redhat.com: the comment above kernel_clone() should be updated]
Link: https://lore.kernel.org/abwvgU17W8wuW2-J@redhat.com
Link: https://lore.kernel.org/20260316151956.563558-1-kartikey406@gmail.com
Fixes:
|
||
|
Peter Zijlstra
|
a26d9208c1 |
Merge branch 'sched/cache'
Merge the cache aware balancer topic branch. # Conflicts: # kernel/sched/topology.c |
||
|
Davidlohr Bueso
|
ee9dce4436 |
futex: Drop CLONE_THREAD requirement for private default hash alloc
Currently need_futex_hash_allocate_default() depends on strict pthread
semantics, abusing CLONE_THREAD. This breaks the non-concurrency
assumptions when doing the mm->futex_ref pcpu allocations, leading to
bugs[0] when sharing the mm in other ways; ie:
BUG: KASAN: slab-use-after-free in futex_hash_put
... where the +1 bias can end up on a percpu counter that mm->futex_ref
no longer points at.
Loosen the check to cover any CLONE_VM clone, except vfork(). Excluding
vfork keeps the existing paths untouched (no overhead), and we can't
race in the first place: either the parent is suspended and the child
runs alone, or mm->futex_ref is already allocated from an earlier
CLONE_VM.
Link: https://lore.kernel.org/all/CAL_bE8LsmCQ-FAtYDuwbJhOkt9p2wwYQwAbMh=PifC=VsiBM6A@mail.gmail.com/ [0]
Fixes:
|
||
|
Linus Torvalds
|
440d6635b2 |
Merge tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull non-MM updates from Andrew Morton:
- "pid: make sub-init creation retryable" (Oleg Nesterov)
Make creation of init in a new namespace more robust by clearing away
some historical cruft which is no longer needed. Also some
documentation fixups
- "selftests/fchmodat2: Error handling and general" (Mark Brown)
Fix and a cleanup for the fchmodat2() syscall selftest
- "lib: polynomial: Move to math/ and clean up" (Andy Shevchenko)
- "hung_task: Provide runtime reset interface for hung task detector"
(Aaron Tomlin)
Give administrators the ability to zero out
/proc/sys/kernel/hung_task_detect_count
- "tools/getdelays: use the static UAPI headers from
tools/include/uapi" (Thomas Weißschuh)
Teach getdelays to use the in-kernel UAPI headers rather than the
system-provided ones
- "watchdog/hardlockup: Improvements to hardlockup" (Mayank Rungta)
Several cleanups and fixups to the hardlockup detector code and its
documentation
- "lib/bch: fix undefined behavior from signed left-shifts" (Josh Law)
A couple of small/theoretical fixes in the bch code
- "ocfs2/dlm: fix two bugs in dlm_match_regions()" (Junrui Luo)
- "cleanup the RAID5 XOR library" (Christoph Hellwig)
A quite far-reaching cleanup to this code. I can't do better than to
quote Christoph:
"The XOR library used for the RAID5 parity is a bit of a mess right
now. The main file sits in crypto/ despite not being cryptography
and not using the crypto API, with the generic implementations
sitting in include/asm-generic and the arch implementations
sitting in an asm/ header in theory. The latter doesn't work for
many cases, so architectures often build the code directly into
the core kernel, or create another module for the architecture
code.
Change this to a single module in lib/ that also contains the
architecture optimizations, similar to the library work Eric
Biggers has done for the CRC and crypto libraries later. After
that it changes to better calling conventions that allow for
smarter architecture implementations (although none is contained
here yet), and uses static_call to avoid indirection function call
overhead"
- "lib/list_sort: Clean up list_sort() scheduling workarounds"
(Kuan-Wei Chiu)
Clean up this library code by removing a hacky thing which was added
for UBIFS, which UBIFS doesn't actually need
- "Fix bugs in extract_iter_to_sg()" (Christian Ehrhardt)
Fix a few bugs in the scatterlist code, add in-kernel tests for the
now-fixed bugs and fix a leak in the test itself
- "kdump: Enable LUKS-encrypted dump target support in ARM64 and
PowerPC" (Coiby Xu)
Enable support of the LUKS-encrypted device dump target on arm64 and
powerpc
- "ocfs2: consolidate extent list validation into block read callbacks"
(Joseph Qi)
Cleanup, simplify, and make more robust ocfs2's validation of extent
list fields (Kernel test robot loves mounting corrupted fs images!)
* tag 'mm-nonmm-stable-2026-04-15-04-20' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (127 commits)
ocfs2: validate group add input before caching
ocfs2: validate bg_bits during freefrag scan
ocfs2: fix listxattr handling when the buffer is full
doc: watchdog: fix typos etc
update Sean's email address
ocfs2: use get_random_u32() where appropriate
ocfs2: split transactions in dio completion to avoid credit exhaustion
ocfs2: remove redundant l_next_free_rec check in __ocfs2_find_path()
ocfs2: validate extent block list fields during block read
ocfs2: remove empty extent list check in ocfs2_dx_dir_lookup_rec()
ocfs2: validate dx_root extent list fields during block read
ocfs2: fix use-after-free in ocfs2_fault() when VM_FAULT_RETRY
ocfs2: handle invalid dinode in ocfs2_group_extend
.get_maintainer.ignore: add Askar
ocfs2: validate bg_list extent bounds in discontig groups
checkpatch: exclude forward declarations of const structs
tools/accounting: handle truncated taskstats netlink messages
taskstats: set version in TGID exit notifications
ocfs2/heartbeat: fix slot mapping rollback leaks on error paths
arm64,ppc64le/kdump: pass dm-crypt keys to kdump kernel
...
|
||
|
Linus Torvalds
|
5bdb4078e1 |
Merge tag 'sched_ext-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext updates from Tejun Heo: - cgroup sub-scheduler groundwork Multiple BPF schedulers can be attached to cgroups and the dispatch path is made hierarchical. This involves substantial restructuring of the core dispatch, bypass, watchdog, and dump paths to be per-scheduler, along with new infrastructure for scheduler ownership enforcement, lifecycle management, and cgroup subtree iteration The enqueue path is not yet updated and will follow in a later cycle - scx_bpf_dsq_reenq() generalized to support any DSQ including remote local DSQs and user DSQs Built on top of this, SCX_ENQ_IMMED guarantees that tasks dispatched to local DSQs either run immediately or get reenqueued back through ops.enqueue(), giving schedulers tighter control over queueing latency Also useful for opportunistic CPU sharing across sub-schedulers - ops.dequeue() was only invoked when the core knew a task was in BPF data structures, missing scheduling property change events and skipping callbacks for non-local DSQ dispatches from ops.select_cpu() Fixed to guarantee exactly one ops.dequeue() call when a task leaves BPF scheduler custody - Kfunc access validation moved from runtime to BPF verifier time, removing runtime mask enforcement - Idle SMT sibling prioritization in the idle CPU selection path - Documentation, selftest, and tooling updates. Misc bug fixes and cleanups * tag 'sched_ext-for-7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext: (134 commits) tools/sched_ext: Add explicit cast from void* in RESIZE_ARRAY() sched_ext: Make string params of __ENUM_set() const tools/sched_ext: Kick home CPU for stranded tasks in scx_qmap sched_ext: Drop spurious warning on kick during scheduler disable sched_ext: Warn on task-based SCX op recursion sched_ext: Rename scx_kf_allowed_on_arg_tasks() to scx_kf_arg_task_ok() sched_ext: Remove runtime kfunc mask enforcement sched_ext: Add verifier-time kfunc context filter sched_ext: Drop redundant rq-locked check from scx_bpf_task_cgroup() sched_ext: Decouple kfunc unlocked-context check from kf_mask sched_ext: Fix ops.cgroup_move() invocation kf_mask and rq tracking sched_ext: Track @p's rq lock across set_cpus_allowed_scx -> ops.set_cpumask sched_ext: Add select_cpu kfuncs to scx_kfunc_ids_unlocked sched_ext: Drop TRACING access to select_cpu kfuncs selftests/sched_ext: Fix wrong DSQ ID in peek_dsq error message sched_ext: Documentation: improve accuracy of task lifecycle pseudo-code selftests/sched_ext: Improve runner error reporting for invalid arguments sched_ext: Documentation: Fix scx_bpf_move_to_local kfunc name sched_ext: Documentation: Add ops.dequeue() to task lifecycle tools/sched_ext: Fix off-by-one in scx_sdt payload zeroing ... |
||
|
Linus Torvalds
|
5c0f43e853 |
Merge tag 'kernel-7.1-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull pid_namespace updates from Christian Brauner:
- pid_namespace: make init creation more flexible
Annotate ->child_reaper accesses with {READ,WRITE}_ONCE() to protect
the unlocked readers from cpu/compiler reordering, and enforce that
pid 1 in a pid namespace is always the first allocated pid (the
set_tid path already required this).
On top of that, allow opening pid_for_children before the pid
namespace init has been created. This lets one process create the pid
namespace and a different process create the init via setns(), which
makes clone3(set_tid) usable in all cases evenly and is particularly
useful to CRIU when restoring nested containers.
A new selftest covers both the basic create-pidns-then-init flow and
the cross-process variant, and a MAINTAINERS entry for the pid
namespace code is added.
- unrelated signal cleanup: update outdated comment for the removed
freezable_schedule()
* tag 'kernel-7.1-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
signal: update outdated comment for removed freezable_schedule()
MAINTAINERS: add a pid namespace entry
selftests: Add tests for creating pidns init via setns
pid_namespace: allow opening pid_for_children before init was created
pid: check init is created first after idr alloc
pid_namespace: avoid optimization of accesses to ->child_reaper
|
||
|
Linus Torvalds
|
7c8a4671dc |
Merge tag 'vfs-7.1-rc1.mount.v2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs
Pull vfs mount updates from Christian Brauner:
- Add FSMOUNT_NAMESPACE flag to fsmount() that creates a new mount
namespace with the newly created filesystem attached to a copy of the
real rootfs. This returns a namespace file descriptor instead of an
O_PATH mount fd, similar to how OPEN_TREE_NAMESPACE works for
open_tree().
This allows creating a new filesystem and immediately placing it in a
new mount namespace in a single operation, which is useful for
container runtimes and other namespace-based isolation mechanisms.
This accompanies OPEN_TREE_NAMESPACE and avoids a needless detour via
OPEN_TREE_NAMESPACE to get the same effect. Will be especially useful
when you mount an actual filesystem to be used as the container
rootfs.
- Currently, creating a new mount namespace always copies the entire
mount tree from the caller's namespace. For containers and sandboxes
that intend to build their mount table from scratch this is wasteful:
they inherit a potentially large mount tree only to immediately tear
it down.
This series adds support for creating a mount namespace that contains
only a clone of the root mount, with none of the child mounts. Two
new flags are introduced:
- CLONE_EMPTY_MNTNS (0x400000000) for clone3(), using the 64-bit flag space
- UNSHARE_EMPTY_MNTNS (0x00100000) for unshare()
Both flags imply CLONE_NEWNS. The resulting namespace contains a
single nullfs root mount with an immutable empty directory. The
intended workflow is to then mount a real filesystem (e.g., tmpfs)
over the root and build the mount table from there.
- Allow MOVE_MOUNT_BENEATH to target the caller's rootfs, allowing to
switch out the rootfs without pivot_root(2).
The traditional approach to switching the rootfs involves
pivot_root(2) or a chroot_fs_refs()-based mechanism that atomically
updates fs->root for all tasks sharing the same fs_struct. This has
consequences for fork(), unshare(CLONE_FS), and setns().
This series instead decomposes root-switching into individually
atomic, locally-scoped steps:
fd_tree = open_tree(-EBADF, "/newroot", OPEN_TREE_CLONE | OPEN_TREE_CLOEXEC);
fchdir(fd_tree);
move_mount(fd_tree, "", AT_FDCWD, "/", MOVE_MOUNT_BENEATH | MOVE_MOUNT_F_EMPTY_PATH);
chroot(".");
umount2(".", MNT_DETACH);
Since each step only modifies the caller's own state, the
fork/unshare/setns races are eliminated by design.
A key step to making this possible is to remove the locked mount
restriction. Originally MOVE_MOUNT_BENEATH doesn't support mounting
beneath a mount that is locked. The locked mount protects the
underlying mount from being revealed. This is a core mechanism of
unshare(CLONE_NEWUSER | CLONE_NEWNS). The mounts in the new mount
namespace become locked. That effectively makes the new mount table
useless as the caller cannot ever get rid of any of the mounts no
matter how useless they are.
We can lift this restriction though. We simply transfer the locked
property from the top mount to the mount beneath. This works because
what we care about is to protect the underlying mount aka the parent.
The mount mounted between the parent and the top mount takes over the
job of protecting the parent mount from the top mount mount. This
leaves us free to remove the locked property from the top mount which
can consequently be unmounted:
unshare(CLONE_NEWUSER | CLONE_NEWNS)
and we inherit a clone of procfs on /proc then currently we cannot
unmount it as:
umount -l /proc
will fail with EINVAL because the procfs mount is locked.
After this series we can now do:
mount --beneath -t tmpfs tmpfs /proc
umount -l /proc
after which a tmpfs mount has been placed beneath the procfs mount.
The tmpfs mount has become locked and the procfs mount has become
unlocked.
This means you can safely modify an inherited mount table after
unprivileged namespace creation.
Afterwards we simply make it possible to move a mount beneath the
rootfs allowing to upgrade the rootfs.
Removing the locked restriction makes this very useful for containers
created with unshare(CLONE_NEWUSER | CLONE_NEWNS) to reshuffle an
inherited mount table safely and MOVE_MOUNT_BENEATH makes it possible
to switch out the rootfs instead of using the costly pivot_root(2).
* tag 'vfs-7.1-rc1.mount.v2' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
selftests/namespaces: remove unused utils.h include from listns_efault_test
selftests/fsmount_ns: add missing TARGETS and fix cap test
selftests/empty_mntns: fix wrong CLONE_EMPTY_MNTNS hex value in comment
selftests/empty_mntns: fix statmount_alloc() signature mismatch
selftests/statmount: remove duplicate wait_for_pid()
mount: always duplicate mount
selftests/filesystems: add MOVE_MOUNT_BENEATH rootfs tests
move_mount: allow MOVE_MOUNT_BENEATH on the rootfs
move_mount: transfer MNT_LOCKED
selftests/filesystems: add clone3 tests for empty mount namespaces
selftests/filesystems: add tests for empty mount namespaces
namespace: allow creating empty mount namespaces
selftests: add FSMOUNT_NAMESPACE tests
selftests/statmount: add statmount_alloc() helper
tools: update mount.h header
mount: add FSMOUNT_NAMESPACE
mount: simplify __do_loopback()
mount: start iterating from start of rbtree
|