From 4ce61d1c7a8ef4c1337fa983a3036d4010e3c19e Mon Sep 17 00:00:00 2001 From: Satyam Sharma Date: Wed, 16 May 2007 23:50:16 -0700 Subject: [PATCH] [BLUETOOTH]: Fix locking in hci_sock_dev_event(). We presently use lock_sock() to acquire a lock on a socket in hci_sock_dev_event(), but this goes BUG because lock_sock() can sleep and we're already holding a read-write spinlock at that point. So, we must use the non-sleeping BH version, bh_lock_sock(). However, hci_sock_dev_event() is called from user context and hence using simply bh_lock_sock() will deadlock against a concurrent softirq that tries to acquire a lock on the same socket. Hence, disabling BH's before acquiring the socket lock and enable them afterwards, is the proper solution to fix socket locking in hci_sock_dev_event(). Signed-off-by: Satyam Sharma Signed-off-by: Marcel Holtmann Signed-off-by: Jiri Kosina Signed-off-by: David S. Miller --- net/bluetooth/hci_sock.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c index bfc9a35bad33..1dae3dfc66a9 100644 --- a/net/bluetooth/hci_sock.c +++ b/net/bluetooth/hci_sock.c @@ -665,7 +665,8 @@ static int hci_sock_dev_event(struct notifier_block *this, unsigned long event, /* Detach sockets from device */ read_lock(&hci_sk_list.lock); sk_for_each(sk, node, &hci_sk_list.head) { - lock_sock(sk); + local_bh_disable(); + bh_lock_sock_nested(sk); if (hci_pi(sk)->hdev == hdev) { hci_pi(sk)->hdev = NULL; sk->sk_err = EPIPE; @@ -674,7 +675,8 @@ static int hci_sock_dev_event(struct notifier_block *this, unsigned long event, hci_dev_put(hdev); } - release_sock(sk); + bh_unlock_sock(sk); + local_bh_enable(); } read_unlock(&hci_sk_list.lock); } -- 2.39.5