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YANG XIN
250120f25f
Starting with MALLOC_CONF=tcache:false and reading or writing thread.tcache.max before first enabling the cache dereferences NULL. The tcache_t embedded in TSD always exists, but tcache->tcache_slow is assigned only by tcache_init(), which is skipped in this case. The tcache_slow settings embedded in TSD are initialized independently. Disabling an already initialized cache does not encounter this missing link, since tcache_init() has already run. Read and update the embedded settings through tsd_tcache_slowp_get(). This allows configuring the limit before the first enable without initializing the cache as a side effect. Add a fresh-thread regression covering the initial read, update while disabled, and preservation of the limit on first enable. A standalone public-API program also reproduces the original crash with tcache:false against a release library.
32 lines
1.1 KiB
C
32 lines
1.1 KiB
C
#include "test/jemalloc_test.h"
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TEST_BEGIN(test_tcache_max_disabled) {
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test_skip_if(opt_tcache);
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tsd_t *tsd = tsd_fetch();
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assert_ptr_null(tsd_tcachep_get(tsd)->tcache_slow,
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"Tcache should not have been initialized");
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size_t max = 0, sz = sizeof(max);
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size_t new_max = opt_tcache_max == 1024 ? 2048 : 1024;
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expect_d_eq(mallctl("thread.tcache.max", &max, &sz, NULL, 0), 0,
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"Unexpected mallctl failure");
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expect_zu_eq(max, sz_s2u(opt_tcache_max),
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"Unexpected default tcache max");
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expect_d_eq(mallctl("thread.tcache.max", NULL, NULL, &new_max,
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sizeof(new_max)), 0, "Unexpected mallctl failure");
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expect_d_eq(mallctl("thread.tcache.max", &max, &sz, NULL, 0), 0,
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"Unexpected mallctl failure");
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expect_zu_eq(max, new_max, "Tcache max should change while disabled");
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expect_false(tsd_tcache_enabled_get(tsd),
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"Changing tcache max should not enable the tcache");
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expect_ptr_null(tsd_tcachep_get(tsd)->tcache_slow,
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"Changing tcache max should not initialize the tcache");
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}
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TEST_END
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int
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main(void) {
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return test_no_reentrancy(test_tcache_max_disabled);
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}
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