diff options
| author | Johan Hedberg <johan.hedberg@intel.com> | 2014-11-12 09:15:50 +0200 |
|---|---|---|
| committer | Marcel Holtmann <marcel@holtmann.org> | 2014-11-12 10:05:25 +0100 |
| commit | f03567040cbf874834c9e3e52b72fdcb672b9bbb (patch) | |
| tree | f7a18f485dad11dec93bc810aa330407c0943035 | |
| parent | c8937a1d112b1a948454f4fa2f9b747fee2a3f66 (diff) | |
| download | linux-f03567040cbf874834c9e3e52b72fdcb672b9bbb.tar.bz2 | |
Bluetooth: Fix l2cap_sock_teardown_cb lockdep warning
Any code calling bt_accept_dequeue() to get a new child socket from a
server socket should use lock_sock_nested to avoid lockdep warnings due
to the parent and child sockets being locked at the same time. The
l2cap_sock_accept() function is already doing this correctly but a
second place calling bt_accept_dequeue() is the code path from
l2cap_sock_teardown_cb() that calls l2cap_sock_cleanup_listen().
This patch fixes the proper nested locking annotation and thereby avoids
the following style of lockdep warning.
[ +0.000224] [ INFO: possible recursive locking detected ]
[ +0.000222] 3.17.0+ #1153 Not tainted
[ +0.000130] ---------------------------------------------
[ +0.000227] l2cap-tester/562 is trying to acquire lock:
[ +0.000210] (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+...}, at: [<c1393f47>] bt_accept_dequeue+0x68/0x11b
[ +0.000467]
but task is already holding lock:
[ +0.000186] (sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP){+.+...}, at: [<c13b949a>] lock_sock+0xa/0xc
[ +0.000421]
other info that might help us debug this:
[ +0.000199] Possible unsafe locking scenario:
[ +0.000117] CPU0
[ +0.000000] ----
[ +0.000000] lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP);
[ +0.000000] lock(sk_lock-AF_BLUETOOTH-BTPROTO_L2CAP);
[ +0.000000]
*** DEADLOCK ***
Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
| -rw-r--r-- | net/bluetooth/l2cap_sock.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c index 31f106e61ca2..ad1cf82fee02 100644 --- a/net/bluetooth/l2cap_sock.c +++ b/net/bluetooth/l2cap_sock.c @@ -1246,7 +1246,7 @@ static void l2cap_sock_teardown_cb(struct l2cap_chan *chan, int err) struct sock *sk = chan->data; struct sock *parent; - lock_sock(sk); + lock_sock_nested(sk, SINGLE_DEPTH_NESTING); parent = bt_sk(sk)->parent; |