From 637d54a5f3a1965fa6aea9e41c4f84abf7a36de9 Mon Sep 17 00:00:00 2001 From: Max Reitz Date: Mon, 22 Jul 2019 15:33:43 +0200 Subject: [PATCH] block: Keep subtree drained in drop_intermediate bdrv_drop_intermediate() calls BdrvChildRole.update_filename(). That may poll, thus changing the graph, which potentially breaks the QLIST_FOREACH_SAFE() loop. Just keep the whole subtree drained. This is probably the right thing to do anyway (dropping nodes while the subtree is not drained seems wrong). Signed-off-by: Max Reitz Reviewed-by: Kevin Wolf Signed-off-by: Kevin Wolf --- block.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/block.c b/block.c index 6db8ecd62b..df3407934b 100644 --- a/block.c +++ b/block.c @@ -4491,6 +4491,7 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, int ret = -EIO; bdrv_ref(top); + bdrv_subtree_drained_begin(top); if (!top->drv || !base->drv) { goto exit; @@ -4562,6 +4563,7 @@ int bdrv_drop_intermediate(BlockDriverState *top, BlockDriverState *base, ret = 0; exit: + bdrv_subtree_drained_end(top); bdrv_unref(top); return ret; }