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authorTakashi Iwai <tiwai@suse.de>2019-04-12 11:37:19 +0200
committerTakashi Iwai <tiwai@suse.de>2019-04-12 12:50:10 +0200
commit7c32ae35fbf9cffb7aa3736f44dec10c944ca18e (patch)
treea1a2a0b1ef3c07979c4bfb8869f97c971580d157 /sound/core
parentf0654ba94e33699b295ce4f3dc73094db6209035 (diff)
downloadlinux-7c32ae35fbf9cffb7aa3736f44dec10c944ca18e.tar.bz2
ALSA: seq: Cover unsubscribe_port() in list_mutex
The call of unsubscribe_port() which manages the group count and module refcount from delete_and_unsubscribe_port() looks racy; it's not covered by the group list lock, and it's likely a cause of the reported unbalance at port deletion. Let's move the call inside the group list_mutex to plug the hole. Reported-by: syzbot+e4c8abb920efa77bace9@syzkaller.appspotmail.com Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/core')
-rw-r--r--sound/core/seq/seq_ports.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/sound/core/seq/seq_ports.c b/sound/core/seq/seq_ports.c
index d964d728681e..ac7556ab531c 100644
--- a/sound/core/seq/seq_ports.c
+++ b/sound/core/seq/seq_ports.c
@@ -547,10 +547,10 @@ static void delete_and_unsubscribe_port(struct snd_seq_client *client,
list_del_init(list);
grp->exclusive = 0;
write_unlock_irq(&grp->list_lock);
- up_write(&grp->list_mutex);
if (!empty)
unsubscribe_port(client, port, grp, &subs->info, ack);
+ up_write(&grp->list_mutex);
}
/* connect two ports */