netconsole: don't call __netpoll_cleanup() while atomic

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

1 files changed, 9 insertions, 6 deletions

diff --git a/drivers/net/netconsole.c b/drivers/net/netconsole.c
index 37add21a3d7d..59ac143dec25 100644
--- a/drivers/net/netconsole.c
+++ b/drivers/net/netconsole.c
@@ -666,6 +666,7 @@ 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) {
@@ -678,15 +679,17 @@ 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) {
-                                        __netpoll_cleanup(&nt->np);
-                                        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);