From patchwork Wed Jan 16 15:54:32 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [072/222] Bluetooth: Add missing lock nesting notation Date: Wed, 16 Jan 2013 05:54:32 -0000 From: Herton Ronaldo Krzesinski X-Patchwork-Id: 212650 Message-Id: <1358351822-7675-73-git-send-email-herton.krzesinski@canonical.com> To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Cc: Gustavo Padovan 3.5.7.3 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Gustavo Padovan commit dc2a0e20fbc85a71c63aa4330b496fda33f6bf80 upstream. This patch fixes the following report, it happens when accepting rfcomm connections: [ 228.165378] ============================================= [ 228.165378] [ INFO: possible recursive locking detected ] [ 228.165378] 3.7.0-rc1-00536-gc1d5dc4 #120 Tainted: G W [ 228.165378] --------------------------------------------- [ 228.165378] bluetoothd/1341 is trying to acquire lock: [ 228.165378] (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+...}, at: [] bt_accept_dequeue+0xa0/0x180 [bluetooth] [ 228.165378] [ 228.165378] but task is already holding lock: [ 228.165378] (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+...}, at: [] rfcomm_sock_accept+0x58/0x2d0 [rfcomm] [ 228.165378] [ 228.165378] other info that might help us debug this: [ 228.165378] Possible unsafe locking scenario: [ 228.165378] [ 228.165378] CPU0 [ 228.165378] ---- [ 228.165378] lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM); [ 228.165378] lock(sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM); [ 228.165378] [ 228.165378] *** DEADLOCK *** [ 228.165378] [ 228.165378] May be due to missing lock nesting notation Signed-off-by: Gustavo Padovan Signed-off-by: Herton Ronaldo Krzesinski --- net/bluetooth/rfcomm/sock.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c index 2df6956..20bd148 100644 --- a/net/bluetooth/rfcomm/sock.c +++ b/net/bluetooth/rfcomm/sock.c @@ -486,7 +486,7 @@ static int rfcomm_sock_accept(struct socket *sock, struct socket *newsock, int f long timeo; int err = 0; - lock_sock(sk); + lock_sock_nested(sk, SINGLE_DEPTH_NESTING); if (sk->sk_type != SOCK_STREAM) { err = -EINVAL; @@ -523,7 +523,7 @@ static int rfcomm_sock_accept(struct socket *sock, struct socket *newsock, int f release_sock(sk); timeo = schedule_timeout(timeo); - lock_sock(sk); + lock_sock_nested(sk, SINGLE_DEPTH_NESTING); } __set_current_state(TASK_RUNNING); remove_wait_queue(sk_sleep(sk), &wait);