diff options
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | malloc/malloc.c | 25 |
2 files changed, 29 insertions, 2 deletions
@@ -1,3 +1,9 @@ +2009-07-16 Ulrich Drepper <drepper@redhat.com> + Jakub Jelinek <jakub@redhat.com> + + * malloc/malloc.c [ATOMIC_FASTBINS] (_int_free): Make check for + corruption thread-safe. + 2009-07-13 Jakub Jelinek <jakub@redhat.com> * include/atomic.h (catomic_compare_and_exchange_val_rel): If arch diff --git a/malloc/malloc.c b/malloc/malloc.c index 0c0182ec0b..a459a2b89d 100644 --- a/malloc/malloc.c +++ b/malloc/malloc.c @@ -4799,8 +4799,29 @@ _int_free(mstate av, mchunkptr p) || __builtin_expect (chunksize (chunk_at_offset (p, size)) >= av->system_mem, 0)) { - errstr = "free(): invalid next size (fast)"; - goto errout; +#ifdef ATOMIC_FASTBINS + /* We might not have a lock at this point and concurrent modifications + of system_mem might have let to a false positive. Redo the test + after getting the lock. */ + if (have_lock + || ({ assert (locked == 0); + mutex_lock(&av->mutex); + locked = 1; + chunk_at_offset (p, size)->size <= 2 * SIZE_SZ + || chunksize (chunk_at_offset (p, size)) >= av->system_mem; + })) +#endif + { + errstr = "free(): invalid next size (fast)"; + goto errout; + } +#ifdef ATOMIC_FASTBINS + if (! have_lock) + { + (void)mutex_unlock(&av->mutex); + locked = 0; + } +#endif } if (__builtin_expect (perturb_byte, 0)) |