From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:53922) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TwEoL-0001Mi-OX for qemu-devel@nongnu.org; Fri, 18 Jan 2013 11:29:02 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TwEoG-0004sO-Dy for qemu-devel@nongnu.org; Fri, 18 Jan 2013 11:28:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32663) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TwEoG-0004rg-57 for qemu-devel@nongnu.org; Fri, 18 Jan 2013 11:28:52 -0500 From: Stefan Hajnoczi Date: Fri, 18 Jan 2013 17:28:34 +0100 Message-Id: <1358526521-24300-2-git-send-email-stefanha@redhat.com> In-Reply-To: <1358526521-24300-1-git-send-email-stefanha@redhat.com> References: <1358526521-24300-1-git-send-email-stefanha@redhat.com> Subject: [Qemu-devel] [PATCH 1/8] block: fix null-pointer bug on error case in block commit List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Anthony Liguori , Jeff Cody , Stefan Hajnoczi From: Jeff Cody This is a bug that was caught by a coverity run by Markus. In the error case when we errored out to exit_restore_open early in the function, 'overlay_bs' was still NULL at that point, although it is used to look up flags and perform a bdrv_reopen(). Move the overlay_bs lookup to where it is needed, and check for NULL before restoring the flags. Also get rid of the unneeded parameter initialization. Reported-By: Markus Armbruster Signed-off-by: Jeff Cody Signed-off-by: Stefan Hajnoczi --- block/commit.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/block/commit.c b/block/commit.c index 61ebdba..553447e 100644 --- a/block/commit.c +++ b/block/commit.c @@ -65,7 +65,7 @@ static void coroutine_fn commit_run(void *opaque) BlockDriverState *active = s->active; BlockDriverState *top = s->top; BlockDriverState *base = s->base; - BlockDriverState *overlay_bs = NULL; + BlockDriverState *overlay_bs; int64_t sector_num, end; int ret = 0; int n = 0; @@ -92,8 +92,6 @@ static void coroutine_fn commit_run(void *opaque) } } - overlay_bs = bdrv_find_overlay(active, top); - end = s->common.len >> BDRV_SECTOR_BITS; buf = qemu_blockalign(top, COMMIT_BUFFER_SIZE); @@ -156,7 +154,8 @@ exit_restore_reopen: if (s->base_flags != bdrv_get_flags(base)) { bdrv_reopen(base, s->base_flags, NULL); } - if (s->orig_overlay_flags != bdrv_get_flags(overlay_bs)) { + overlay_bs = bdrv_find_overlay(active, top); + if (overlay_bs && s->orig_overlay_flags != bdrv_get_flags(overlay_bs)) { bdrv_reopen(overlay_bs, s->orig_overlay_flags, NULL); } -- 1.8.0.2