[PATCH 5.2 73/85] mm/z3fold.c: fix lock/unlock imbalance in z3fold_page_isolate

[Greg Kroah-Hartman]

From: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>

commit 14108b9131a47ff18a3c640f583eb2d625c75c0d upstream.

Fix lock/unlock imbalance by unlocking *zhdr* before return.

Addresses Coverity ID 1452811 ("Missing unlock")

Link: http://lkml.kernel.org/r/20190826030634.GA4379@embeddedor
Fixes: d776aaa9895e ("mm/z3fold.c: fix race between migration and destruction")
Signed-off-by: Gustavo A. R. Silva <gustavo@xxxxxxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Henry Burns <henrywolfeburns@xxxxxxxxx>
Cc: Vitaly Wool <vitalywool@xxxxxxxxx>
Cc: Shakeel Butt <shakeelb@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 mm/z3fold.c |    1 +
 1 file changed, 1 insertion(+)

--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -1408,6 +1408,7 @@ static bool z3fold_page_isolate(struct p
 				 * should freak out.
 				 */
 				WARN(1, "Z3fold is experiencing kref problems\n");
+				z3fold_page_unlock(zhdr);
 				return false;
 			}
 			z3fold_page_unlock(zhdr);