block: do not leak memory in bio_copy_user_iov()

BugLink: https://bugs.launchpad.net/bugs/1838116
commit a3761c3c91209b58b6f33bf69dd8bb8ec0c9d925 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/block/bio.c b/block/bio.c
index 66a7feb5414db13522c571ef67861d32d8975c4b..9c64edac75d5055896516efc9dc28c43d41f673d 100644 (file)
--- a/block/bio.c
+++ b/block/bio.c
@@ -1316,8 +1316,11 @@ 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;