[PATCH 5.15 101/128] mac80211: fix locking in ieee80211_start_ap error path

[Greg Kroah-Hartman]

From: Johannes Berg <johannes.berg@xxxxxxxxx>

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@xxxxxxxxxxxxxxx
Fixes: 295b02c4be74 ("mac80211: Add FILS discovery support")
Reported-and-tested-by: syzbot+11c342e5e30e9539cabd@xxxxxxxxxxxxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20211220090836.cee3d59a1915.I36bba9b79dc2ff4d57c3c7aa30dff9a003fe8c5c@changeid
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 net/mac80211/cfg.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -1226,7 +1226,10 @@ static int ieee80211_start_ap(struct wip
 	return 0;
 
 error:
+	mutex_lock(&local->mtx);
 	ieee80211_vif_release_channel(sdata);
+	mutex_unlock(&local->mtx);
+
 	return err;
 }