Fix race in free sanity check.

This commit is contained in:
Ulrich Drepper 2010-05-06 04:42:46 -07:00
parent d84acf388e
commit 5f24d53acb
3 changed files with 15334 additions and 15326 deletions

15324
ChangeLog

File diff suppressed because it is too large Load Diff

15321
ChangeLog.17 Normal file

File diff suppressed because it is too large Load Diff

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@ -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). */