6.1-stable review patch. If anyone has any objections, please let me know.
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From: Iulia Tanasescu iulia.tanasescu@nxp.com
[ Upstream commit 9bde7c3b3ad0e1f39d6df93dd1c9caf63e19e50f ]
This updates iso_sock_accept to use nested locking for the parent socket, to avoid lockdep warnings caused because the parent and child sockets are locked by the same thread:
[ 41.585683] ============================================ [ 41.585688] WARNING: possible recursive locking detected [ 41.585694] 6.12.0-rc6+ #22 Not tainted [ 41.585701] -------------------------------------------- [ 41.585705] iso-tester/3139 is trying to acquire lock: [ 41.585711] ffff988b29530a58 (sk_lock-AF_BLUETOOTH) at: bt_accept_dequeue+0xe3/0x280 [bluetooth] [ 41.585905] but task is already holding lock: [ 41.585909] ffff988b29533a58 (sk_lock-AF_BLUETOOTH) at: iso_sock_accept+0x61/0x2d0 [bluetooth] [ 41.586064] other info that might help us debug this: [ 41.586069] Possible unsafe locking scenario:
[ 41.586072] CPU0 [ 41.586076] ---- [ 41.586079] lock(sk_lock-AF_BLUETOOTH); [ 41.586086] lock(sk_lock-AF_BLUETOOTH); [ 41.586093] *** DEADLOCK ***
[ 41.586097] May be due to missing lock nesting notation
[ 41.586101] 1 lock held by iso-tester/3139: [ 41.586107] #0: ffff988b29533a58 (sk_lock-AF_BLUETOOTH) at: iso_sock_accept+0x61/0x2d0 [bluetooth]
Fixes: ccf74f2390d6 ("Bluetooth: Add BTPROTO_ISO socket type") Signed-off-by: Iulia Tanasescu iulia.tanasescu@nxp.com Signed-off-by: Luiz Augusto von Dentz luiz.von.dentz@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- net/bluetooth/iso.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c index ff15d5192768..437cbeaa9619 100644 --- a/net/bluetooth/iso.c +++ b/net/bluetooth/iso.c @@ -964,7 +964,11 @@ static int iso_sock_accept(struct socket *sock, struct socket *newsock, long timeo; int err = 0;
- lock_sock(sk); + /* Use explicit nested locking to avoid lockdep warnings generated + * because the parent socket and the child socket are locked on the + * same thread. + */ + lock_sock_nested(sk, SINGLE_DEPTH_NESTING);
timeo = sock_rcvtimeo(sk, flags & O_NONBLOCK);
@@ -995,7 +999,7 @@ static int iso_sock_accept(struct socket *sock, struct socket *newsock, release_sock(sk);
timeo = wait_woken(&wait, TASK_INTERRUPTIBLE, timeo); - lock_sock(sk); + lock_sock_nested(sk, SINGLE_DEPTH_NESTING); } remove_wait_queue(sk_sleep(sk), &wait);