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lock(&hdev->lock); lock(sk_lock-AF_BLUETOOTH-BTPROTO_ISO); lock(&hdev->lock); *** DEADLOCK *** 1 lock held by iso-tester/2950: 0: ffff888197c39278 (sk_lock-AF_BLUETOOTH-BTPROTO_ISO){+.+.}-{0:0}, at: iso_sock_listen+0x91/0x8d0 Signed-off-by: Iulia Tanasescu --- net/bluetooth/iso.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c index 8af75d37b14c..d1608387fd85 100644 --- a/net/bluetooth/iso.c +++ b/net/bluetooth/iso.c @@ -1069,6 +1069,7 @@ static int iso_sock_connect(struct socket *sock, struct sockaddr *addr, return err; } +/* This function requires the caller to hold sk lock */ static int iso_listen_bis(struct sock *sk) { struct hci_dev *hdev; @@ -1095,7 +1096,15 @@ static int iso_listen_bis(struct sock *sk) if (!hdev) return -EHOSTUNREACH; + /* Prevent sk from being freed whilst unlocked */ + sock_hold(sk); + + /* To avoid circular locking dependencies, + * hdev should be locked first before sk. + */ + release_sock(sk); hci_dev_lock(hdev); + lock_sock(sk); /* Fail if user set invalid QoS */ if (iso_pi(sk)->qos_user_set && !check_bcast_qos(&iso_pi(sk)->qos)) { @@ -1128,7 +1137,13 @@ static int iso_listen_bis(struct sock *sk) hci_dev_put(hdev); unlock: + /* Unlock order should be in reverse from lock order. */ + release_sock(sk); hci_dev_unlock(hdev); + lock_sock(sk); + + sock_put(sk); + return err; }