From 8d3dd037d947ce96c42c376ef0bb5e5c6ef96cbe Mon Sep 17 00:00:00 2001 From: Hanna Reitz Date: Mon, 15 Nov 2021 15:53:57 +0100 Subject: [PATCH] stream: Traverse graph after modification bdrv_cor_filter_drop() modifies the block graph. That means that other parties can also modify the block graph before it returns. Therefore, we cannot assume that the result of a graph traversal we did before remains valid afterwards. We should thus fetch `base` and `unfiltered_base` afterwards instead of before. Signed-off-by: Hanna Reitz Reviewed-by: Kevin Wolf Reviewed-by: Vladimir Sementsov-Ogievskiy Message-Id: <20211111120829.81329-2-hreitz@redhat.com> Signed-off-by: Kevin Wolf Message-Id: <20211115145409.176785-2-kwolf@redhat.com> Signed-off-by: Hanna Reitz --- block/stream.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/block/stream.c b/block/stream.c index 97bee482dc..e45113aed6 100644 --- a/block/stream.c +++ b/block/stream.c @@ -54,8 +54,8 @@ static int stream_prepare(Job *job) { StreamBlockJob *s = container_of(job, StreamBlockJob, common.job); BlockDriverState *unfiltered_bs = bdrv_skip_filters(s->target_bs); - BlockDriverState *base = bdrv_filter_or_cow_bs(s->above_base); - BlockDriverState *unfiltered_base = bdrv_skip_filters(base); + BlockDriverState *base; + BlockDriverState *unfiltered_base; Error *local_err = NULL; int ret = 0; @@ -63,6 +63,9 @@ static int stream_prepare(Job *job) bdrv_cor_filter_drop(s->cor_filter_bs); s->cor_filter_bs = NULL; + base = bdrv_filter_or_cow_bs(s->above_base); + unfiltered_base = bdrv_skip_filters(base); + if (bdrv_cow_child(unfiltered_bs)) { const char *base_id = NULL, *base_fmt = NULL; if (unfiltered_base) { -- 2.11.0