diff options
| author | Sergio Lopez <slp@redhat.com> | 2019-09-11 12:03:16 +0200 |
|---|---|---|
| committer | Max Reitz <mreitz@redhat.com> | 2019-09-16 15:31:12 +0200 |
| commit | d876bf676f5e7c6aa9ac64555e48cba8734ecb2f (patch) | |
| tree | a59919ba03b035259cabd05193df4ac224cbd7ed /blockjob.c | |
| parent | c34dc07f9f01cf686e512f939aece744723072cd (diff) | |
blockjob: update nodes head while removing all bdrv
block_job_remove_all_bdrv() iterates through job->nodes, calling
bdrv_root_unref_child() for each entry. The call to the latter may
reach child_job_[can_]set_aio_ctx(), which will also attempt to
traverse job->nodes, potentially finding entries that where freed
on previous iterations.
To avoid this situation, update job->nodes head on each iteration to
ensure that already freed entries are no longer linked to the list.
RHBZ: https://bugzilla.redhat.com/show_bug.cgi?id=1746631
Signed-off-by: Sergio Lopez <slp@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20190911100316.32282-1-mreitz@redhat.com
Reviewed-by: Sergio Lopez <slp@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>
Diffstat (limited to 'blockjob.c')
| -rw-r--r-- | blockjob.c | 17 |
1 files changed, 13 insertions, 4 deletions
diff --git a/blockjob.c b/blockjob.c index 2abed0f551..c6e20e2fcd 100644 --- a/blockjob.c +++ b/blockjob.c @@ -175,14 +175,23 @@ static const BdrvChildRole child_job = { void block_job_remove_all_bdrv(BlockJob *job) { - GSList *l; - for (l = job->nodes; l; l = l->next) { + /* + * bdrv_root_unref_child() may reach child_job_[can_]set_aio_ctx(), + * which will also traverse job->nodes, so consume the list one by + * one to make sure that such a concurrent access does not attempt + * to process an already freed BdrvChild. + */ + while (job->nodes) { + GSList *l = job->nodes; BdrvChild *c = l->data; + + job->nodes = l->next; + bdrv_op_unblock_all(c->bs, job->blocker); bdrv_root_unref_child(c); + + g_slist_free_1(l); } - g_slist_free(job->nodes); - job->nodes = NULL; } bool block_job_has_bdrv(BlockJob *job, BlockDriverState *bs) |