Commit a2ff19f7 authored by Takashi Iwai's avatar Takashi Iwai

ALSA: seq: Clear client entry before deleting else at closing

When releasing a client, we need to clear the clienttab[] entry at
first, then call snd_seq_queue_client_leave().  Otherwise, the
in-flight cell in the queue might be picked up by the timer interrupt
via snd_seq_check_queue() before calling snd_seq_queue_client_leave(),
and it's delivered to another queue while the client is clearing
queues.  This may eventually result in an uncleared cell remaining in
a queue, and the later snd_seq_pool_delete() may need to wait for a
long time until the event gets really processed.

By moving the clienttab[] clearance at the beginning of release, any
event delivery of a cell belonging to this client will fail at a later
point, since snd_seq_client_ptr() returns NULL.  Thus the cell that
was picked up by the timer interrupt will be returned immediately
without further delivery, and the long stall of snd_seq_delete_pool()
can be avoided, too.

Cc: <>
Signed-off-by: default avatarTakashi Iwai <>
parent d0f83306
......@@ -255,12 +255,12 @@ static int seq_free_client1(struct snd_seq_client *client)
if (!client)
return 0;
spin_lock_irqsave(&clients_lock, flags);
clienttablock[client->number] = 1;
clienttab[client->number] = NULL;
spin_unlock_irqrestore(&clients_lock, flags);
if (client->pool)
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