Re: [PATCH 06/19] block/stream: fix -Werror=maybe-uninitialized false-positives

[Vladimir Sementsov-Ogievskiy]

On 28.03.24 13:20, marcandre.lureau@redhat.com wrote:
> From: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> ../block/stream.c:193:19: error: ‘unfiltered_bs’ may be used uninitialized 
> [-Werror=maybe-uninitialized]
> ../block/stream.c:176:5: error: ‘len’ may be used uninitialized 
> [-Werror=maybe-uninitialized]
> trace/trace-block.h:906:9: error: ‘ret’ may be used uninitialized 
> [-Werror=maybe-uninitialized]
>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Again, same false-positives, because of WITH_GRAPH_RDLOCK_GUARD()..

Didn't you try to change WITH_ macros somehow, so that compiler believe in our 
good intentions?

Actually, "unused variable initialization" is bad thing too.

Anyway, if no better solution for now:
Acked-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>

> ---
>   block/stream.c | 6 +++---
>   1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/block/stream.c b/block/stream.c
> index 7031eef12b..9076203193 100644
> --- a/block/stream.c
> +++ b/block/stream.c
> @@ -155,8 +155,8 @@ static void stream_clean(Job *job)
>   static int coroutine_fn stream_run(Job *job, Error **errp)
>   {
>       StreamBlockJob *s = container_of(job, StreamBlockJob, common.job);
> -    BlockDriverState *unfiltered_bs;
> -    int64_t len;
> +    BlockDriverState *unfiltered_bs = NULL;
> +    int64_t len = -1;
>       int64_t offset = 0;
>       int error = 0;
>       int64_t n = 0; /* bytes */
> @@ -177,7 +177,7 @@ static int coroutine_fn stream_run(Job *job, Error **errp)
>   
>       for ( ; offset < len; offset += n) {
>           bool copy;
> -        int ret;
> +        int ret = -1;
>   
>           /* Note that even when no rate limit is applied we need to yield
>            * with no pending I/O here so that bdrv_drain_all() returns.

--
Best regards,
Vladimir