mm/z3fold.c: fix lock/unlock imbalance in z3fold_page_isolate

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@embeddedor.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Henry Burns <henrywolfeburns@gmail.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/mm/z3fold.c b/mm/z3fold.c
index 39d0a8a40e6670bc8f87ea1f6c3dd463d9b8417c..8374b18ebe9a3c73d69dc8eb553c6bc3f7ce84ac 100644 (file)
--- a/mm/z3fold.c
+++ b/mm/z3fold.c
@@ -1408,6 +1408,7 @@ static bool z3fold_page_isolate(struct page *page, isolate_mode_t mode)
                                 * should freak out.
                                 */
                                WARN(1, "Z3fold is experiencing kref problems\n");
+                               z3fold_page_unlock(zhdr);
                                return false;
                        }
                        z3fold_page_unlock(zhdr);