lkml.org 
[lkml]   [2019]   [Jun]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH AUTOSEL 5.1 05/60] ALSA: seq: Cover unsubscribe_port() in list_mutex
Date
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
\
 
 \ /
  Last update: 2019-06-05 01:23    [W:0.523 / U:0.524 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site