[PULL,12/27] block: avoid potential deadlock during bdrv_graph_wrlock() in bdrv_close()

Commit Message

Kevin Wolf Oct. 31, 2023, 6:59 p.m. UTC

From: Fiona Ebner <[e-mail]>

by passing the BlockDriverState along, so the held AioContext can be
dropped before polling. See commit 31b2ddfea3 ("graph-lock: Unlock the
AioContext while polling") which introduced this functionality for
more information.

The only way to reach bdrv_close() is via bdrv_unref() and for calling
that the BlockDriverState's AioContext lock is supposed to be held.

Signed-off-by: Fiona Ebner <[e-mail]>
Message-ID: <[e-mail]>
Reviewed-by: Kevin Wolf <[e-mail]>
Signed-off-by: Kevin Wolf <[e-mail]>
---
 block.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/block.c b/block.c
index f9cf05ddcf..a527aa1a4c 100644
--- a/block.c
+++ b/block.c
@@ -5200,7 +5200,7 @@  static void bdrv_close(BlockDriverState *bs)
         bs->drv = NULL;
     }
 
-    bdrv_graph_wrlock(NULL);
+    bdrv_graph_wrlock(bs);
     QLIST_FOREACH_SAFE(child, &bs->children, next, next) {
         bdrv_unref_child(bs, child);
     }