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| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2022-10-03 11:58:09 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2022-11-22 14:31:25 +0000 |
| commit | 32c64139eef90920af88e85c07c168fcada73935 (patch) | |
| tree | dfd5db0319795c8db54b8687652137208b52634a | |
| parent | e0bde778546db86042bdf4f4b8eca7f38d01a02e (diff) | |
| download | glibc-32c64139eef90920af88e85c07c168fcada73935.tar.gz | |
malloc: Don't use __libc_free for tcache cleanup
__libc_free must only be used for memory given out by __libc_malloc
and similar public apis, but tcache stores a cache of already freed
pointers and itself is allocated using internal malloc apis. Strong
double free detection in __libc_free breaks tcache_thread_shutdown,
so use a cut down version of free to reset tcache entries.
| -rw-r--r-- | malloc/malloc.c | 33 |
1 files changed, 31 insertions, 2 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c index 701adbebca..7ada0e5ae0 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -3205,6 +3205,35 @@ tcache_get (size_t tc_idx) return (void *) e; } +/* Cut down __libc_free for cleaning up tcache entries. */ +static void +tcache_libc_free (void *mem) +{ + int err = errno; + mchunkptr p = mem2chunk(mem); + if (chunk_is_mmapped (p)) + { + /* See if the dynamic brk/mmap threshold needs adjusting. + Dumped fake mmapped chunks do not affect the threshold. */ + if (!mp_.no_dyn_threshold + && chunksize_nomask (p) > mp_.mmap_threshold + && chunksize_nomask (p) <= DEFAULT_MMAP_THRESHOLD_MAX) + { + mp_.mmap_threshold = chunksize (p); + mp_.trim_threshold = 2 * mp_.mmap_threshold; + LIBC_PROBE (memory_mallopt_free_dyn_thresholds, 2, + mp_.mmap_threshold, mp_.trim_threshold); + } + munmap_chunk (p); + } + else + { + mstate ar_ptr = arena_for_chunk (p); + _int_free (ar_ptr, p, 0); + } + __set_errno (err); +} + static void tcache_thread_shutdown (void) { @@ -3230,11 +3259,11 @@ tcache_thread_shutdown (void) malloc_printerr ("tcache_thread_shutdown(): " "unaligned tcache chunk detected"); tcache_tmp->entries[i] = REVEAL_PTR (e->next); - __libc_free (e); + tcache_libc_free (e); } } - __libc_free (tcache_tmp); + tcache_libc_free (tcache_tmp); } static void |