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>

1 files changed, 8 insertions, 1 deletions

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: