Message ID | 82f8ffaa908befab90470a79e0feb105af9aad84.1358264426.git.jcody@redhat.com |
---|---|
State | New |
Headers | show |
Jeff Cody <jcody@redhat.com> writes: > 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 <armbru@redhat.com> > Signed-off-by: Jeff Cody <jcody@redhat.com> > --- > block/commit.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > 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); > } The move doesn't change anything in the "no error" case, because we don't change active, top or the BDS chain connecting them between old and new location. Reviewed-by: Markus Armbruster <armbru@redhat.com>
On Tue, Jan 15, 2013 at 10:47:24AM -0500, Jeff Cody wrote: > 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 <armbru@redhat.com> > Signed-off-by: Jeff Cody <jcody@redhat.com> > --- > block/commit.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) Thanks, applied to my block tree: https://github.com/stefanha/qemu/commits/block Stefan
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); }
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 <armbru@redhat.com> Signed-off-by: Jeff Cody <jcody@redhat.com> --- block/commit.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)