[ALSA] Fix possible deadlocks in sequencer at removal of ports

Fix possible rwsem deadlocks in sequencer code at removal of
sequencer ports.  The list_lock of port group can be double
locked.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>

1 files changed, 1 insertions, 1 deletions

diff --git a/sound/core/seq/seq_ports.c b/sound/core/seq/seq_ports.c
index d88153438d69..eefd1cf872b4 100644
--- a/sound/core/seq/seq_ports.c
+++ b/sound/core/seq/seq_ports.c
@@ -245,9 +245,9 @@ static void clear_subscriber_list(struct snd_seq_client *client,
                                 list_del(&subs->dest_list);
                         else
                                 list_del(&subs->src_list);
+                        up_write(&agrp->list_mutex);
                         unsubscribe_port(c, aport, agrp, &subs->info, 1);
                         kfree(subs);
-                        up_write(&agrp->list_mutex);
                         snd_seq_port_unlock(aport);
                         snd_seq_client_unlock(c);
                 }