[PATCH] softmac: Fix deadlock of wx_set_essid with assoc work

The essid wireless extension does deadlock against the assoc mutex,
as we don't unlock the assoc mutex when flushing the workqueue, which
also holds the lock.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Willy Tarreau <w@1wt.eu>

diff --git a/net/ieee80211/softmac/ieee80211softmac_wx.c b/net/ieee80211/softmac/ieee80211softmac_wx.c
index fb58e03b3fbda3497245f3b484c01db14a343e4c..c3c39ed53a2a4d91537f3dda600c48e8e138d809 100644 (file)
--- a/net/ieee80211/softmac/ieee80211softmac_wx.c
+++ b/net/ieee80211/softmac/ieee80211softmac_wx.c
@@ -74,8 +74,8 @@ ieee80211softmac_wx_set_essid(struct net_device *net_dev,
        struct ieee80211softmac_auth_queue_item *authptr;
        int length = 0;
 
+check_assoc_again:
        mutex_lock(&sm->associnfo.mutex);
-
        /* Check if we're already associating to this or another network
         * If it's another network, cancel and start over with our new network
         * If it's our network, ignore the change, we're already doing it!
@@ -98,13 +98,18 @@ ieee80211softmac_wx_set_essid(struct net_device *net_dev,
                                cancel_delayed_work(&authptr->work);
                        sm->associnfo.bssvalid = 0;
                        sm->associnfo.bssfixed = 0;
-                       flush_scheduled_work();
                        sm->associnfo.associating = 0;
                        sm->associnfo.associated = 0;
+                       /* We must unlock to avoid deadlocks with the assoc workqueue
+                        * on the associnfo.mutex */
+                       mutex_unlock(&sm->associnfo.mutex);
+                       flush_scheduled_work();
+                       /* Avoid race! Check assoc status again. Maybe someone started an
+                        * association while we flushed. */
+                       goto check_assoc_again;
                }
        }
 
-
        sm->associnfo.static_essid = 0;
        sm->associnfo.assoc_wait = 0;