From: Max Reitz <mre...@redhat.com>
mirror_exit_common() may be called twice (if it is called from
mirror_prepare() and fails, it will be called from mirror_abort()
again).
In such a case, many of the pointers in the MirrorBlockJob object will
already be freed. This can be seen most reliably for s->target, which
is set to NULL (and then dereferenced by blk_bs()).
Cc: qemu-sta...@nongnu.org
Fixes: 737efc1eda23b904fbe0e66b37715fb0e5c3e58b
Signed-off-by: Max Reitz <mre...@redhat.com>
Reviewed-by: John Snow <js...@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsement...@virtuozzo.com>
Message-id: 20191014153931.20699-2-mre...@redhat.com
Signed-off-by: Max Reitz <mre...@redhat.com>
(cherry picked from commit f93c3add3a773e0e3f6277e5517583c4ad3a43c2)
Signed-off-by: Michael Roth <mdr...@linux.vnet.ibm.com>
---
block/mirror.c | 13 +++++++++----
1 file changed, 9 insertions(+), 4 deletions(-)
diff --git a/block/mirror.c b/block/mirror.c
index 9f5c59ece1..0e3f7923cf 100644
--- a/block/mirror.c
+++ b/block/mirror.c
@@ -618,11 +618,11 @@ static int mirror_exit_common(Job *job)
{
MirrorBlockJob *s = container_of(job, MirrorBlockJob, common.job);
BlockJob *bjob = &s->common;
- MirrorBDSOpaque *bs_opaque = s->mirror_top_bs->opaque;
+ MirrorBDSOpaque *bs_opaque;
AioContext *replace_aio_context = NULL;
- BlockDriverState *src = s->mirror_top_bs->backing->bs;
- BlockDriverState *target_bs = blk_bs(s->target);
- BlockDriverState *mirror_top_bs = s->mirror_top_bs;
+ BlockDriverState *src;
+ BlockDriverState *target_bs;
+ BlockDriverState *mirror_top_bs;
Error *local_err = NULL;
bool abort = job->ret < 0;
int ret = 0;
@@ -632,6 +632,11 @@ static int mirror_exit_common(Job *job)
}
s->prepared = true;
+ mirror_top_bs = s->mirror_top_bs;
+ bs_opaque = mirror_top_bs->opaque;
+ src = mirror_top_bs->backing->bs;
+ target_bs = blk_bs(s->target);
+
if (bdrv_chain_contains(src, target_bs)) {
bdrv_unfreeze_backing_chain(mirror_top_bs, target_bs);
}
--
2.17.1
