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authorJohannes Berg <johannes@sipsolutions.net>2009-08-12 22:21:21 +0200
committerJohn W. Linville <linville@tuxdriver.com>2009-08-14 09:14:07 -0400
commit36e6fea84905512ea776707e82b5b435220efc17 (patch)
treedb588e7dbbfcf0fa47f4954344a03961e960c898 /net/wireless/core.c
parent70bdb6b275d789ddf05c3a858e6b57715539394b (diff)
cfg80211: check for and abort dangling scan requests
If you trigger a scan request on an interface and then take it down, or rmmod the module or unplug the device the driver might "forget" to cancel the scan request. That is a bug in the driver, but the current behaviour is that we just hang endlessly waiting for the netdev refcount to become 0 which it never will. To improve robustness, check for this situation in cfg80211, warn about it and clean up behind the driver. I don't just clean up silently because it's likely that the driver also has some internal state it has now leaked. Additionally, this fixes a locking bug, clearing the scan_req pointer should be done under the rdev lock. Finally, we also need to _wait_ for the scan work and not just abort it since it might be pending and wanting to do a cleanup. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net/wireless/core.c')
-rw-r--r--net/wireless/core.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/net/wireless/core.c b/net/wireless/core.c
index e630648fef79..35d83bedfe5b 100644
--- a/net/wireless/core.c
+++ b/net/wireless/core.c
@@ -601,8 +601,8 @@ void wiphy_unregister(struct wiphy *wiphy)
mutex_unlock(&cfg80211_mutex);
+ flush_work(&rdev->scan_done_wk);
cancel_work_sync(&rdev->conn_work);
- cancel_work_sync(&rdev->scan_done_wk);
kfree(rdev->scan_req);
flush_work(&rdev->event_work);
}
@@ -728,6 +728,13 @@ static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
#endif
break;
case NETDEV_UNREGISTER:
+ cfg80211_lock_rdev(rdev);
+
+ if (WARN_ON(rdev->scan_req && rdev->scan_req->dev == dev)) {
+ rdev->scan_req->aborted = true;
+ ___cfg80211_scan_done(rdev);
+ }
+
mutex_lock(&rdev->devlist_mtx);
/*
* It is possible to get NETDEV_UNREGISTER
@@ -746,6 +753,7 @@ static int cfg80211_netdev_notifier_call(struct notifier_block * nb,
#endif
}
mutex_unlock(&rdev->devlist_mtx);
+ cfg80211_unlock_rdev(rdev);
break;
case NETDEV_PRE_UP:
if (!(wdev->wiphy->interface_modes & BIT(wdev->iftype)))