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Re: [Qemu-devel] [PATCH] migration: Appease coverity, skip empty block t
From: |
Philippe Mathieu-Daudé |
Subject: |
Re: [Qemu-devel] [PATCH] migration: Appease coverity, skip empty block trees |
Date: |
Fri, 22 Jun 2018 17:24:07 -0300 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 |
On 06/22/2018 05:11 PM, John Snow wrote:
> If a tree consists exclusively of implicit filter nodes, we might crash
> QEMU. This configuration should not exist in practice, but if it did,
> skipping it would be fine.
>
> For the purposes of debug builds, throw an assert to remind us that
> this configuration is truly unexpected, but if it's compiled out we
> will cope just fine.
Well... with your explanation, your patch is correct.
But do we really want to maintain a 'debug with assert' vs 'production
without assertions' codebase?
$ git grep g_assert_not_reached | egrep -v '^tests/' | wc -l
406
Does Coverity require all these 406 lines to behave with a
"configuration [that] should not exist in practice"?
>
> Signed-off-by: John Snow <address@hidden>
> ---
> migration/block-dirty-bitmap.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c
> index 3bafbbdc4c..02725293dd 100644
> --- a/migration/block-dirty-bitmap.c
> +++ b/migration/block-dirty-bitmap.c
> @@ -287,6 +287,10 @@ static int init_dirty_bitmap_migration(void)
> while (bs && bs->drv && bs->implicit) {
> bs = backing_bs(bs);
> }
> + if (!bs) {
> + g_assert_not_reached();
> + continue;
Can we choose one or the other?
> + }
>
> for (bitmap = bdrv_dirty_bitmap_next(bs, NULL); bitmap;
> bitmap = bdrv_dirty_bitmap_next(bs, bitmap))
>