block: do not leak memory in bio_copy_user_iov()

When bio_add_pc_page() fails in bio_copy_user_iov() we should free
the page we just allocated otherwise we are leaking it.

Cc: linux-block@vger.kernel.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: stable@vger.kernel.org
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 4 insertions, 1 deletions

diff --git a/block/bio.c b/block/bio.c
index b64cedc7f87c..716510ecd7ff 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -1298,8 +1298,11 @@ struct bio *bio_copy_user_iov(struct request_queue *q,
                         }
                 }
 
-                if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes)
+                if (bio_add_pc_page(q, bio, page, bytes, offset) < bytes) {
+                        if (!map_data)
+                                __free_page(page);
                         break;
+                }
 
                 len -= bytes;
                 offset = 0;