mac80211: fix scan abort sanity checks

Since sometimes mac80211 queues up a scan request
to only act on it later, it must be allowed to
(internally) cancel a not-yet-running scan, e.g.
when the interface is taken down. This condition
was missing since we always checked only the
local->scanning variable which isn't yet set in
that situation.

Reported-by: Luis R. Rodriguez <mcgrof@gmail.com>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index c46ac01e2a8f..88a9a1be314a 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -288,10 +288,14 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted)
 
         mutex_lock(&local->scan_mtx);
 
-        if (WARN_ON(!local->scanning)) {
-                mutex_unlock(&local->scan_mtx);
-                return;
-        }
+        /*
+         * It's ok to abort a not-yet-running scan (that
+         * we have one at all will be verified by checking
+         * local->scan_req next), but not to complete it
+         * successfully.
+         */
+        if (WARN_ON(!local->scanning && !aborted))
+                aborted = true;
 
         if (WARN_ON(!local->scan_req)) {
                 mutex_unlock(&local->scan_mtx);