diff options
| author | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2024-06-24 16:42:09 +0300 |
|---|---|---|
| committer | Luiz Augusto von Dentz <luiz.von.dentz@intel.com> | 2024-06-28 21:32:02 +0300 |
| commit | f1a8f402f13f94263cf349216c257b2985100927 (patch) | |
| tree | 001137512a41f55d65b4baaf9a492716c987e9bd /net/bluetooth/l2cap_sock.c | |
| parent | 1cc18c2ab2e8c54c355ea7c0423a636e415a0c23 (diff) | |
| download | linux-f1a8f402f13f94263cf349216c257b2985100927.tar.xz | |
Bluetooth: L2CAP: Fix deadlock
This fixes the following deadlock introduced by 39a92a55be13
("bluetooth/l2cap: sync sock recv cb and release")
============================================
WARNING: possible recursive locking detected
6.10.0-rc3-g4029dba6b6f1 #6823 Not tainted
--------------------------------------------
kworker/u5:0/35 is trying to acquire lock:
ffff888002ec2510 (&chan->lock#2/1){+.+.}-{3:3}, at:
l2cap_sock_recv_cb+0x44/0x1e0
but task is already holding lock:
ffff888002ec2510 (&chan->lock#2/1){+.+.}-{3:3}, at:
l2cap_get_chan_by_scid+0xaf/0xd0
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(&chan->lock#2/1);
lock(&chan->lock#2/1);
*** DEADLOCK ***
May be due to missing lock nesting notation
3 locks held by kworker/u5:0/35:
#0: ffff888002b8a940 ((wq_completion)hci0#2){+.+.}-{0:0}, at:
process_one_work+0x750/0x930
#1: ffff888002c67dd0 ((work_completion)(&hdev->rx_work)){+.+.}-{0:0},
at: process_one_work+0x44e/0x930
#2: ffff888002ec2510 (&chan->lock#2/1){+.+.}-{3:3}, at:
l2cap_get_chan_by_scid+0xaf/0xd0
To fix the original problem this introduces l2cap_chan_lock at
l2cap_conless_channel to ensure that l2cap_sock_recv_cb is called with
chan->lock held.
Fixes: 89e856e124f9 ("bluetooth/l2cap: sync sock recv cb and release")
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>
Diffstat (limited to 'net/bluetooth/l2cap_sock.c')
| -rw-r--r-- | net/bluetooth/l2cap_sock.c | 13 |
1 files changed, 1 insertions, 12 deletions
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index 962aa11ce3de..ba437c6f6ee5 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1489,18 +1489,9 @@ static int l2cap_sock_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb) struct l2cap_pinfo *pi; int err; - /* To avoid race with sock_release, a chan lock needs to be added here - * to synchronize the sock. - */ - l2cap_chan_hold(chan); - l2cap_chan_lock(chan); sk = chan->data; - - if (!sk) { - l2cap_chan_unlock(chan); - l2cap_chan_put(chan); + if (!sk) return -ENXIO; - } pi = l2cap_pi(sk); lock_sock(sk); @@ -1552,8 +1543,6 @@ static int l2cap_sock_recv_cb(struct l2cap_chan *chan, struct sk_buff *skb) done: release_sock(sk); - l2cap_chan_unlock(chan); - l2cap_chan_put(chan); return err; } |