gthread: fix minor errno problem in GCond

The return value from `g_cond_wait_until()` is calculated, based on the
value of `errno` after reacquiring the mutex.  This is a problem because
`errno` can be overwritten in the case the mutex is contended (in which
case the slow-path code will re-enter the kernel).

Perform the calculation before reacquiring the mutex.

See merge request GNOME/glib!958
This commit is contained in:
Allison Karlitskaya 2019-06-28 10:15:33 +02:00
parent 01bc57576b
commit d92f22ab47

View File

@ -1441,6 +1441,7 @@ g_cond_wait_until (GCond *cond,
struct timespec span;
guint sampled;
int res;
gboolean success;
if (end_time < 0)
return FALSE;
@ -1460,9 +1461,10 @@ g_cond_wait_until (GCond *cond,
sampled = cond->i[0];
g_mutex_unlock (mutex);
res = syscall (__NR_futex, &cond->i[0], (gsize) FUTEX_WAIT_PRIVATE, (gsize) sampled, &span);
success = (res < 0 && errno == ETIMEDOUT) ? FALSE : TRUE;
g_mutex_lock (mutex);
return (res < 0 && errno == ETIMEDOUT) ? FALSE : TRUE;
return success;
}
#endif