From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756533Ab3CYBUg (ORCPT ); Sun, 24 Mar 2013 21:20:36 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:34137 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756349Ab3CYBQg (ORCPT ); Sun, 24 Mar 2013 21:16:36 -0400 Message-Id: <20130325010527.444644366@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 25 Mar 2013 01:05:56 +0000 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: akpm@linux-foundation.org, Veaceslav Falico , Neil Horman , "David S. Miller" Subject: [ 032/104] netconsole: dont call __netpoll_cleanup() while atomic Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit In-Reply-To: <20130325010524.240972766@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:f137:78a:b654:affb X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Veaceslav Falico [ Upstream commit 3f315bef23075ea8a98a6fe4221a83b83456d970 ] __netpoll_cleanup() is called in netconsole_netdev_event() while holding a spinlock. Release/acquire the spinlock before/after it and restart the loop. Also, disable the netconsole completely, because we won't have chance after the restart of the loop, and might end up in a situation where nt->enabled == 1 and nt->np.dev == NULL. Signed-off-by: Veaceslav Falico Acked-by: Neil Horman Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- drivers/net/netconsole.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c index 01b104e..bff6908 100644 --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -630,6 +630,7 @@ static int netconsole_netdev_event(struct notifier_block *this, goto done; spin_lock_irqsave(&target_list_lock, flags); +restart: list_for_each_entry(nt, &target_list, list) { netconsole_target_get(nt); if (nt->np.dev == dev) { @@ -642,20 +643,17 @@ static int netconsole_netdev_event(struct notifier_block *this, case NETDEV_UNREGISTER: /* * rtnl_lock already held + * we might sleep in __netpoll_cleanup() */ - if (nt->np.dev) { - spin_unlock_irqrestore( - &target_list_lock, - flags); - __netpoll_cleanup(&nt->np); - spin_lock_irqsave(&target_list_lock, - flags); - dev_put(nt->np.dev); - nt->np.dev = NULL; - } + spin_unlock_irqrestore(&target_list_lock, flags); + __netpoll_cleanup(&nt->np); + spin_lock_irqsave(&target_list_lock, flags); + dev_put(nt->np.dev); + nt->np.dev = NULL; nt->enabled = 0; stopped = true; - break; + netconsole_target_put(nt); + goto restart; } } netconsole_target_put(nt);