From: Neil Horman <nhorman@tuxdriver.com>
Date: Wed, 13 Oct 2010 16:01:52 +0000 (+0000)
Subject: bonding: Fix netconsole to not deadlock on rmmod
X-Git-Tag: v2.6.37-rc1~147^2~89
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=3b410a310b48a8e7de3438957635093596ad5ca5

bonding: Fix netconsole to not deadlock on rmmod

Netconsole calls netpoll_cleanup on receipt of a NETDEVICE_UNREGISTER event.
The notifier subsystem calls these event handlers with rtnl_lock held, which
netpoll_cleanup also takes, resulting in deadlock.  Fix this by calling the
__netpoll_cleanup interior function instead, and fixing up the additional
pointers.

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index ca142c47b2e4..94255f09093d 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -678,7 +678,14 @@ static int netconsole_netdev_event(struct notifier_block *this,
 				strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
 				break;
 			case NETDEV_UNREGISTER:
-				netpoll_cleanup(&nt->np);
+				/*
+				 * rtnl_lock already held
+				 */
+				if (nt->np.dev) {
+					__netpoll_cleanup(&nt->np);
+					dev_put(nt->np.dev);
+					nt->np.dev = NULL;
+				}
 				/* Fall through */
 			case NETDEV_GOING_DOWN:
 			case NETDEV_BONDING_DESLAVE: