commit
b980955236922ae6106774511c5c05003d3ad225 upstream.
Commit
6133705494bb introduced a circular lock dependency because
posix_cpu_timers_exit() is called by release_task(), which is holding
a writer lock on tasklist_lock, and this can cause a deadlock since
kill_fasync() gets called with nonblocking_pool.lock taken.
There's no reason why kill_fasync() needs to be taken while the random
pool is locked, so move it out to fix this locking dependency.
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reported-by: Russ Dill <Russ.Dill@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
int reserved)
{
unsigned long flags;
int reserved)
{
unsigned long flags;
/* Hold lock while accounting */
spin_lock_irqsave(&r->lock, flags);
/* Hold lock while accounting */
spin_lock_irqsave(&r->lock, flags);
else
r->entropy_count = reserved;
else
r->entropy_count = reserved;
- if (r->entropy_count < random_write_wakeup_thresh) {
- wake_up_interruptible(&random_write_wait);
- kill_fasync(&fasync, SIGIO, POLL_OUT);
- }
+ if (r->entropy_count < random_write_wakeup_thresh)
+ wakeup_write = 1;
}
DEBUG_ENT("debiting %zu entropy credits from %s%s\n",
}
DEBUG_ENT("debiting %zu entropy credits from %s%s\n",
spin_unlock_irqrestore(&r->lock, flags);
spin_unlock_irqrestore(&r->lock, flags);
+ if (wakeup_write) {
+ wake_up_interruptible(&random_write_wait);
+ kill_fasync(&fasync, SIGIO, POLL_OUT);
+ }
+