Messages in this thread Patch in this message | | | From | Sasha Levin <> | Subject | [PATCH AUTOSEL 5.1 05/60] ALSA: seq: Cover unsubscribe_port() in list_mutex | Date | Tue, 4 Jun 2019 19:21:15 -0400 |
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From: Takashi Iwai <tiwai@suse.de>
[ Upstream commit 7c32ae35fbf9cffb7aa3736f44dec10c944ca18e ]
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> Signed-off-by: Sasha Levin <sashal@kernel.org> --- sound/core/seq/seq_ports.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/sound/core/seq/seq_ports.c b/sound/core/seq/seq_ports.c index a31e16cc012e..16289aefb443 100644 --- a/sound/core/seq/seq_ports.c +++ b/sound/core/seq/seq_ports.c @@ -550,10 +550,10 @@ 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 */ -- 2.20.1
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