From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Veaceslav Falico , Neil Horman , "David S. Miller" Subject: [ 04/72] netconsole: dont call __netpoll_cleanup() while atomic Date: Tue, 26 Mar 2013 15:50:47 -0700 Message-Id: <20130326224920.155448260@linuxfoundation.org> In-Reply-To: <20130326224919.675227837@linuxfoundation.org> References: <20130326224919.675227837@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-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: Greg Kroah-Hartman --- drivers/net/netconsole.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) --- a/drivers/net/netconsole.c +++ b/drivers/net/netconsole.c @@ -626,6 +626,7 @@ static int netconsole_netdev_event(struc 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) { @@ -637,21 +638,18 @@ static int netconsole_netdev_event(struc case NETDEV_JOIN: case NETDEV_UNREGISTER: /* + * we might sleep in __netpoll_cleanup() * rtnl_lock already held */ - 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);