Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S968188AbXFHIAu (ORCPT ); Fri, 8 Jun 2007 04:00:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S938510AbXFHH0M (ORCPT ); Fri, 8 Jun 2007 03:26:12 -0400 Received: from 216-99-217-87.dsl.aracnet.com ([216.99.217.87]:55405 "EHLO sous-sol.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S938502AbXFHH0K (ORCPT ); Fri, 8 Jun 2007 03:26:10 -0400 Message-Id: <20070608072241.418537000@sous-sol.org> References: <20070608072127.352723000@sous-sol.org> User-Agent: quilt/0.46-1 Date: Fri, 08 Jun 2007 00:22:21 -0700 From: Chris Wright To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, David Miller , bunk@stusta.de, Satyam Sharma , Marcel Holtmann , Jiri Kosina , Greg Kroah-Hartman Subject: [patch 54/54] BLUETOOTH: Fix locking in hci_sock_dev_event(). Content-Disposition: inline; filename=bluetooth-fix-locking-in-hci_sock_dev_event.patch Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2028 Lines: 57 -stable review patch. If anyone has any objections, please let us know. --------------------- From: Satyam Sharma 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 Signed-off-by: Chris Wright Signed-off-by: Greg Kroah-Hartman --- net/bluetooth/hci_sock.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- linux-2.6.21.4.orig/net/bluetooth/hci_sock.c +++ linux-2.6.21.4/net/bluetooth/hci_sock.c @@ -656,7 +656,8 @@ static int hci_sock_dev_event(struct not /* 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; @@ -665,7 +666,8 @@ static int hci_sock_dev_event(struct not hci_dev_put(hdev); } - release_sock(sk); + bh_unlock_sock(sk); + local_bh_enable(); } read_unlock(&hci_sk_list.lock); } -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/