diff options
| author | Max Reitz <mreitz@redhat.com> | 2019-10-14 17:39:28 +0200 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2019-10-28 11:49:37 +0100 |
| commit | f93c3add3a773e0e3f6277e5517583c4ad3a43c2 (patch) | |
| tree | 619a0e6b629320f905b7abede7cdd39c374a5681 /block | |
| parent | e87a09d6251b28d1494a3728441d8fdb93a8d57d (diff) | |
mirror: Do not dereference invalid pointers
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-stable@nongnu.org
Fixes: 737efc1eda23b904fbe0e66b37715fb0e5c3e58b
Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Message-id: 20191014153931.20699-2-mreitz@redhat.com
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/mirror.c | 13 |
1 files changed, 9 insertions, 4 deletions
diff --git a/block/mirror.c b/block/mirror.c index 454365ce00..bb17cfce31 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -620,11 +620,11 @@ 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; @@ -634,6 +634,11 @@ 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); } |