From 56a3d5af927be34e94ff356648cbf0213552afd3 Mon Sep 17 00:00:00 2001 Message-Id: <56a3d5af927be34e94ff356648cbf0213552afd3.1376572530.git.minovotn@redhat.com> In-Reply-To: <1ab1cadd348058496d2f900c3d4ac4b7c325d3e6.1376572530.git.minovotn@redhat.com> References: <1ab1cadd348058496d2f900c3d4ac4b7c325d3e6.1376572530.git.minovotn@redhat.com> From: Markus Armbruster Date: Wed, 14 Aug 2013 15:12:53 +0200 Subject: [PATCH 11/11] block: fix null-pointer bug on error case in block commit RH-Author: Markus Armbruster Message-id: <1376493173-5884-4-git-send-email-armbru@redhat.com> Patchwork-id: 53412 O-Subject: [PATCH 6.5 qemu-kvm 3/3] block: fix null-pointer bug on error case in block commit Bugzilla: 880990 RH-Acked-by: Jeffrey Cody RH-Acked-by: Luiz Capitulino RH-Acked-by: Kevin Wolf RH-Acked-by: Fam Zheng 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 (cherry picked from commit 6d759117d3fd28e38c49c56c9de206cc718d32fa) Signed-off-by: Markus Armbruster --- block/commit.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) Signed-off-by: Michal Novotny --- block/commit.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/block/commit.c b/block/commit.c index 68c89e6..26eafcc 100644 --- a/block/commit.c +++ b/block/commit.c @@ -92,7 +92,7 @@ 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; @@ -119,8 +119,6 @@ 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); @@ -183,7 +181,8 @@ 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); } -- 1.7.11.7