diff options
| author | Ulrich Drepper <drepper@redhat.com> | 2010-05-06 04:42:46 -0700 |
|---|---|---|
| committer | Ulrich Drepper <drepper@redhat.com> | 2010-05-06 04:42:46 -0700 |
| commit | 5f24d53acb2cd02ffb4ac925c0244e4f1f854499 (patch) | |
| tree | 003e29b340698e10773e68adc30f8dcf8f345b5a /malloc | |
| parent | d84acf388ed8b3f162dda0512139095bfc268beb (diff) | |
| download | glibc-5f24d53acb2cd02ffb4ac925c0244e4f1f854499.tar.gz | |
Fix race in free sanity check.
Diffstat (limited to 'malloc')
| -rw-r--r-- | malloc/malloc.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/malloc/malloc.c b/malloc/malloc.c index 722b1d4961..9594be4cbd 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -4859,6 +4859,7 @@ _int_free(mstate av, mchunkptr p) #ifdef ATOMIC_FASTBINS mchunkptr fd; mchunkptr old = *fb; + unsigned int old_idx = ~0u; do { /* Another simple check: make sure the top of the bin is not the @@ -4868,15 +4869,17 @@ _int_free(mstate av, mchunkptr p) errstr = "double free or corruption (fasttop)"; goto errout; } - if (old != NULL - && __builtin_expect (fastbin_index(chunksize(old)) != idx, 0)) - { - errstr = "invalid fastbin entry (free)"; - goto errout; - } + if (old != NULL) + old_idx = fastbin_index(chunksize(old)); p->fd = fd = old; } while ((old = catomic_compare_and_exchange_val_rel (fb, p, fd)) != fd); + + if (fd != NULL && __builtin_expect (old_idx != idx, 0)) + { + errstr = "invalid fastbin entry (free)"; + goto errout; + } #else /* Another simple check: make sure the top of the bin is not the record we are going to add (i.e., double free). */ |