mac80211: fix locking in ieee80211_start_ap error path

We need to hold the local->mtx to release the channel context,
as even encoded by the lockdep_assert_held() there. Fix it.

Cc: stable@vger.kernel.org
Fixes: bcf334812b99 ("mac80211: Add FILS discovery support")
Reported-and-tested-by: syzbot+11c342e5e30e9539cabd@syzkaller.appspotmail.com
Link: https://lore.kernel.org/r/20211220090836.cee3d59a1915.I36bba9b79dc2ff4d57c3c7aa30dff9a003fe8c5c@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index bd3d3195097faf2726614a6c32adc567b57455d3..2d0dd69f9753ced49e03a40628e4c88550a64208 100644 (file)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1264,7 +1264,10 @@ static int ieee80211_start_ap(struct wiphy *wiphy, struct net_device *dev,
        return 0;
 
 error:
+       mutex_lock(&local->mtx);
        ieee80211_vif_release_channel(sdata);
+       mutex_unlock(&local->mtx);
+
        return err;
 }