From 18775ff32697ab6e1fd47989673bf1de54d0d942 Mon Sep 17 00:00:00 2001 From: Vladimir Sementsov-Ogievskiy Date: Thu, 28 Sep 2017 15:03:00 +0300 Subject: [PATCH] block/mirror: check backing in bdrv_mirror_top_refresh_filename Backing may be zero after failed bdrv_attach_child in bdrv_set_backing_hd, which leads to SIGSEGV. Signed-off-by: Vladimir Sementsov-Ogievskiy Message-id: 20170928120300.58164-1-vsementsov@virtuozzo.com Reviewed-by: John Snow Signed-off-by: Max Reitz --- block/mirror.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/block/mirror.c b/block/mirror.c index 459b80f8f32e..3b6f0c577221 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -1058,6 +1058,11 @@ static int coroutine_fn bdrv_mirror_top_pdiscard(BlockDriverState *bs, static void bdrv_mirror_top_refresh_filename(BlockDriverState *bs, QDict *opts) { + if (bs->backing == NULL) { + /* we can be here after failed bdrv_attach_child in + * bdrv_set_backing_hd */ + return; + } bdrv_refresh_filename(bs->backing->bs); pstrcpy(bs->exact_filename, sizeof(bs->exact_filename), bs->backing->bs->filename);