Commit 8530ea3c9b ("Kbuild: remove structleak gcc plugin") dropped
the stackinit GCC plugins, so there is no longer a gradient of test
coverage. Collapse the now identical USER_PASS, BYREF_PASS, STRONG_PASS
into a single INSTRUMENTED_PASS definition.
Signed-off-by: Kees Cook <kees@kernel.org>
Under -ftrivial-auto-var-init= the initialization is emitted where a
variable is declared. A switch dispatch that reaches a case label below
the declaration, or a goto that jumps past it, never reaches that point,
so the variable was left uninitialized.
Commit 9cf016e6b4 ("lib: test_stackinit.c: XFAIL switch variable init
tests") marked test_switch_1_none and test_switch_2_none as expected
failures, noting the test should be retained "so that we can evaluate
compiler fixes". Clang 24 emits the initialization on the jumps that
bypass the declaration, so make the expectation depend on the compiler
version instead of failing unconditionally.
Add test_goto_none as well. The existing cases only cover a declaration
sitting between a switch and its first case label, while the compiler
change covers plain goto too.
GCC continues to initialize only at the declaration, and reports as much
with -Wtrivial-auto-var-init, so it keeps the expected-failure path.
Link: https://github.com/llvm/llvm-project/pull/181937
Link: https://github.com/KSPP/linux/issues/125
Link: https://llvm.org/pr44916
Assisted-by: LLM
Signed-off-by: Justin Stitt <justinstitt@google.com>
Link: https://patch.msgid.link/20261002-kspp-125-v1-1-91286a454fda@google.com
Signed-off-by: Kees Cook <kees@kernel.org>
gcc-12 and higher support the -ftrivial-auto-var-init= flag, after
gcc-8 is the minimum version, this is half of the supported ones, and
the vast majority of the versions that users are actually likely to
have, so it seems like a good time to stop having the fallback
plugin implementation
Older toolchains are still able to build kernels normally without
this plugin, but won't be able to use variable initialization..
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
The byte initialization values used with -ftrivial-auto-var-init=pattern
(CONFIG_INIT_STACK_ALL_PATTERN=y) depends on the compiler, architecture,
and byte position relative to struct member types. On i386 with Clang,
this includes the 0xFF value, which means it looks like nothing changes
between the leaf byte filling pass and the expected "stack wiping"
pass of the stackinit test.
Use the byte fill value of 0x99 instead, fixing the test for i386 Clang
builds.
Reported-by: ernsteiswuerfel
Closes: https://github.com/ClangBuiltLinux/linux/issues/2071
Fixes: 8c30d32b1a ("lib/test_stackinit: Handle Clang auto-initialization pattern")
Tested-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20250304225606.work.030-kees@kernel.org
Signed-off-by: Kees Cook <kees@kernel.org>
Kees Cook