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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Herbert Xu <herbert@gondor.apana.org.au>,
        Johannes Berg <johannes.berg@intel.com>
Subject: [PATCH 4.20 010/183] mac80211: Free mpath object when rhashtable insertion fails
Date:   Mon, 25 Feb 2019 22:09:43 +0100
Message-Id: <20190225195056.398128381@linuxfoundation.org>
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4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Herbert Xu <herbert@gondor.apana.org.au>

commit 4ff3a9d14c6c06eaa4e5976c61599ea2bd9e81b2 upstream.

When rhashtable insertion fails the mesh table code doesn't free
the now-orphan mesh path object.  This patch fixes that.

Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/mac80211/mesh_pathtbl.c |   17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

--- a/net/mac80211/mesh_pathtbl.c
+++ b/net/mac80211/mesh_pathtbl.c
@@ -436,17 +436,15 @@ struct mesh_path *mesh_path_add(struct i
 	} while (unlikely(ret == -EEXIST && !mpath));
 	spin_unlock_bh(&tbl->walk_lock);
 
-	if (ret && ret != -EEXIST)
-		return ERR_PTR(ret);
-
-	/* At this point either new_mpath was added, or we found a
-	 * matching entry already in the table; in the latter case
-	 * free the unnecessary new entry.
-	 */
-	if (ret == -EEXIST) {
+	if (ret) {
 		kfree(new_mpath);
+
+		if (ret != -EEXIST)
+			return ERR_PTR(ret);
+
 		new_mpath = mpath;
 	}
+
 	sdata->u.mesh.mesh_paths_generation++;
 	return new_mpath;
 }
@@ -481,6 +479,9 @@ int mpp_path_add(struct ieee80211_sub_if
 		hlist_add_head_rcu(&new_mpath->walk_list, &tbl->walk_head);
 	spin_unlock_bh(&tbl->walk_lock);
 
+	if (ret)
+		kfree(new_mpath);
+
 	sdata->u.mesh.mpp_paths_generation++;
 	return ret;
 }