Commit c7230763 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>
[bwh: Backported to 3.2: deleted log statement is slightly different]
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 61b48f3b
......@@ -421,7 +421,6 @@ 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;
......@@ -434,14 +433,8 @@ 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) {
snd_printk(KERN_WARNING "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);
......
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