From 6d759117d3fd28e38c49c56c9de206cc718d32fa Mon Sep 17 00:00:00 2001 From: Jeff Cody Date: Tue, 15 Jan 2013 10:47:24 -0500 Subject: block: fix null-pointer bug on error case in block commit This is a bug that was caught by a coverity run by Markus. In the error case when we errored out to exit_restore_open early in the function, 'overlay_bs' was still NULL at that point, although it is used to look up flags and perform a bdrv_reopen(). Move the overlay_bs lookup to where it is needed, and check for NULL before restoring the flags. Also get rid of the unneeded parameter initialization. Reported-By: Markus Armbruster Signed-off-by: Jeff Cody Signed-off-by: Stefan Hajnoczi --- block/commit.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'block') diff --git a/block/commit.c b/block/commit.c index 61ebdba..553447e 100644 --- a/block/commit.c +++ b/block/commit.c @@ -65,7 +65,7 @@ static void coroutine_fn commit_run(void *opaque) BlockDriverState *active = s->active; BlockDriverState *top = s->top; BlockDriverState *base = s->base; - BlockDriverState *overlay_bs = NULL; + BlockDriverState *overlay_bs; int64_t sector_num, end; int ret = 0; int n = 0; @@ -92,8 +92,6 @@ static void coroutine_fn commit_run(void *opaque) } } - overlay_bs = bdrv_find_overlay(active, top); - end = s->common.len >> BDRV_SECTOR_BITS; buf = qemu_blockalign(top, COMMIT_BUFFER_SIZE); @@ -156,7 +154,8 @@ exit_restore_reopen: if (s->base_flags != bdrv_get_flags(base)) { bdrv_reopen(base, s->base_flags, NULL); } - if (s->orig_overlay_flags != bdrv_get_flags(overlay_bs)) { + overlay_bs = bdrv_find_overlay(active, top); + if (overlay_bs && s->orig_overlay_flags != bdrv_get_flags(overlay_bs)) { bdrv_reopen(overlay_bs, s->orig_overlay_flags, NULL); } -- cgit v1.1