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Add double free detection using slab bitmap for debug build

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Add a sanity check for double free issue in the arena in case that the tcache has been flushed.
This commit is contained in:
Guangli Dai
2022-08-09 16:39:02 -07:00
committed by Qi Wang
parent 36366f3c4c
commit 42daa1ac44
2 changed files with 96 additions and 25 deletions
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50
test/unit/double_free.c
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@@ -21,6 +21,15 @@ test_double_free_post() {
safety_check_set_abort(NULL);
}
bool tcache_enabled() {
bool enabled;
size_t sz = sizeof(enabled);
assert_d_eq(
mallctl("thread.tcache.enabled", &enabled, &sz, NULL, 0), 0,
"Unexpected mallctl failure");
return enabled;
}
TEST_BEGIN(test_large_double_free_tcache) {
test_skip_if(!config_opt_safety_checks);
/*
@@ -72,15 +81,8 @@ TEST_END
TEST_BEGIN(test_small_double_free_tcache) {
test_skip_if(!config_debug);
test_skip_if(opt_debug_double_free_max_scan == 0);
bool tcache_enabled;
size_t sz = sizeof(tcache_enabled);
assert_d_eq(
mallctl("thread.tcache.enabled", &tcache_enabled, &sz, NULL, 0), 0,
"Unexpected mallctl failure");
test_skip_if(!tcache_enabled);
test_skip_if(!tcache_enabled());
test_double_free_pre();
char *ptr = malloc(1);
@@ -101,10 +103,40 @@ TEST_BEGIN(test_small_double_free_tcache) {
}
TEST_END
TEST_BEGIN(test_small_double_free_arena) {
test_skip_if(!config_debug);
test_skip_if(!tcache_enabled());
test_double_free_pre();
/*
* Allocate one more pointer to keep the slab partially used after
* flushing the cache.
*/
char *ptr1 = malloc(1);
char *ptr = malloc(1);
bool guarded = extent_is_guarded(tsdn_fetch(), ptr);
free(ptr);
if (!guarded) {
mallctl("thread.tcache.flush", NULL, NULL, NULL, 0);
free(ptr);
} else {
/*
* Skip because guarded extents may unguard immediately on
* deallocation, in which case the second free will crash before
* reaching the intended safety check.
*/
fake_abort_called = true;
}
test_double_free_post();
free(ptr1);
}
TEST_END
int
main(void) {
return test(
test_large_double_free_no_tcache,
test_large_double_free_tcache,
test_small_double_free_tcache);
test_small_double_free_tcache,
test_small_double_free_arena);
}