Commit 3ce4befa authored by Takashi Iwai's avatar Takashi Iwai Committed by Ben Hutchings

ALSA: seq: Don't handle loop timeout at snd_seq_pool_done()

commit 37a7ea4a upstream.

snd_seq_pool_done() syncs with closing of all opened threads, but it
aborts the wait loop with a timeout, and proceeds to the release
resource even if not all threads have been closed.  The timeout was 5
seconds, and if you run a crazy stuff, it can exceed easily, and may
result in the access of the invalid memory address -- this is what
syzkaller detected in a bug report.

As a fix, let the code graduate from naiveness, simply remove the loop
timeout.

BugLink: http://lkml.kernel.org/r/CACT4Y+YdhDV2H5LLzDTJDVF-qiYHUHhtRaW4rbb4gUhTCQB81w@mail.gmail.comReported-by: default avatarDmitry Vyukov <dvyukov@google.com>
Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 5630d3ac
......@@ -419,7 +419,6 @@ int snd_seq_pool_done(struct snd_seq_pool *pool)
{
unsigned long flags;
struct snd_seq_event_cell *ptr;
int max_count = 5 * HZ;
if (snd_BUG_ON(!pool))
return -EINVAL;
......@@ -432,14 +431,8 @@ int snd_seq_pool_done(struct snd_seq_pool *pool)
if (waitqueue_active(&pool->output_sleep))
wake_up(&pool->output_sleep);
while (atomic_read(&pool->counter) > 0) {
if (max_count == 0) {
pr_warn("ALSA: snd_seq_pool_done timeout: %d cells remain\n", atomic_read(&pool->counter));
break;
}
while (atomic_read(&pool->counter) > 0)
schedule_timeout_uninterruptible(1);
max_count--;
}
/* release all resources */
spin_lock_irqsave(&pool->lock, flags);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment