mirror/guile
mirror/guile
1
Fork 0
mirror of https://git.savannah.gnu.org/git/guile.git synced 2025-05-20 11:40:18 +02:00
Code Activity

Fix fat_mutex owner corruption and other problems in fat_mutex_unlock.

Browse source 
Fixes <https://debbugs.gnu.org/22152>.
Reported by Iwan Aucamp <aucampia@gmail.com>.

* libguile/threads.c (fat_mutex_unlock): Avoid repeatedly decrementing
  m->level and changing the owner of the mutex when 'block_self' returns
  EINTR.  Unblock asyncs before calling scm_syserror.  Refactor the code
  to clarify the EINTR loop, and to make it more apparent that the async
  blocks and unblocks are balanced.
This commit is contained in:
Mark H Weaver 2015-12-18 02:29:48 -05:00
parent 4b60562820
commit 1e86dc32a4
1 changed files with 36 additions and 51 deletions
Download patch file Download diff file Expand all files Collapse all files

87
libguile/threads.c
View file

@ -1607,70 +1607,55 @@ fat_mutex_unlock (SCM mutex, SCM cond,
}
}
if (m->level > 0)
m->level--;
if (m->level == 0)
{
/* Change the owner of MUTEX. */
t->mutexes = scm_delq_x (mutex, t->mutexes);
m->owner = unblock_from_queue (m->waiting);
}
if (! (SCM_UNBNDP (cond)))
{
c = SCM_CONDVAR_DATA (cond);
while (1)
t->block_asyncs++;
do
{
int brk = 0;
if (m->level > 0)
m->level--;
if (m->level == 0)
{
/* Change the owner of MUTEX. */
t->mutexes = scm_delq_x (mutex, t->mutexes);
m->owner = unblock_from_queue (m->waiting);
}
t->block_asyncs++;
err = block_self (c->waiting, cond, &m->lock, waittime);
scm_i_pthread_mutex_unlock (&m->lock);
if (err == 0)
{
ret = 1;
brk = 1;
}
else if (err == ETIMEDOUT)
{
ret = 0;
brk = 1;
}
else if (err != EINTR)
{
errno = err;
scm_syserror (NULL);
}
if (err == EINTR)
{
t->block_asyncs--;
scm_async_click ();
if (brk)
{
if (relock)
scm_lock_mutex_timed (mutex, SCM_UNDEFINED, owner);
t->block_asyncs--;
break;
}
scm_remember_upto_here_2 (cond, mutex);
t->block_asyncs--;
scm_async_click ();
scm_remember_upto_here_2 (cond, mutex);
scm_i_scm_pthread_mutex_lock (&m->lock);
scm_i_scm_pthread_mutex_lock (&m->lock);
t->block_asyncs++;
}
}
while (err == EINTR);
if (err == 0)
ret = 1;
else if (err == ETIMEDOUT)
ret = 0;
else
{
t->block_asyncs--;
errno = err;
scm_syserror (NULL);
}
if (relock)
scm_lock_mutex_timed (mutex, SCM_UNDEFINED, owner);
t->block_asyncs--;
}
else
{
if (m->level > 0)
m->level--;
if (m->level == 0)
{
/* Change the owner of MUTEX. */
t->mutexes = scm_delq_x (mutex, t->mutexes);
m->owner = unblock_from_queue (m->waiting);
}
scm_i_pthread_mutex_unlock (&m->lock);
ret = 1;
}