From: Johannes Berg <johannes.berg@intel.com>
Date: Mon, 20 Dec 2021 09:22:40 +0000 (+0100)
Subject: mac80211: fix locking in ieee80211_start_ap error path
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=c1d1ec4db5f7264cfc21993e59e8f2dcecf4b44f;p=linux.git

mac80211: fix locking in ieee80211_start_ap error path

commit 87a270625a89fc841f1a7e21aae6176543d8385c upstream.

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: 295b02c4be74 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index d3f62fd12f0b5..1bf83b8d84021 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1226,7 +1226,10 @@ 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;
 }