diff mbox series

[PULL,4/9] stream: Fix AioContext locking during bdrv_graph_wrlock()

Message ID 20231121115302.52214-5-kwolf@redhat.com (mailing list archive)
State New, archived
Headers show
Series [PULL,1/9] hw/ide/ahci: fix legacy software reset | expand

Commit Message

Kevin Wolf Nov. 21, 2023, 11:52 a.m. UTC 
In stream_prepare(), we need to temporarily drop the AioContext lock
that job_prepare_locked() took for us while calling the graph write lock
functions which can poll.

All block nodes related to this block job are in the same AioContext, so
we can pass any of them to bdrv_graph_wrlock()/ bdrv_graph_wrunlock().
Unfortunately, the one that we picked is base, which can be NULL - and
in this case the AioContext lock is not released and deadlocks can
occur.

Fix this by passing s->target_bs, which is never NULL.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-ID: <20231115172012.112727-4-kwolf@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 block/stream.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/block/stream.c b/block/stream.c
index e3aa696289..01fe7c0f16 100644
--- a/block/stream.c
+++ b/block/stream.c
@@ -99,9 +99,9 @@  static int stream_prepare(Job *job)
             }
         }
 
-        bdrv_graph_wrlock(base);
+        bdrv_graph_wrlock(s->target_bs);
         bdrv_set_backing_hd_drained(unfiltered_bs, base, &local_err);
-        bdrv_graph_wrunlock(base);
+        bdrv_graph_wrunlock(s->target_bs);
 
         /*
          * This call will do I/O, so the graph can change again from here on.