linux-kernel - NAK: [PATCH][next] dm space maps: Fix uninitialized variable r2

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Message-ID: <fe127847-f8ee-20aa-5613-19b8a110c712@canonical.com>
Date:   Fri, 21 May 2021 10:47:51 +0100
From:   Colin Ian King <colin.king@...onical.com>
To:     Alasdair Kergon <agk@...hat.com>,
        Mike Snitzer <snitzer@...hat.com>, dm-devel@...hat.com,
        Joe Thornber <ejt@...hat.com>
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: NAK: [PATCH][next] dm space maps: Fix uninitialized variable r2

On 21/05/2021 10:40, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> In the case where recursing(mm) is true variable r2 is not
> inintialized and an uninitialized value is being used in the
> call combine_errors later on. Fix this by setting r2 to zero.
> 
> Addresses-Coverity: ("Uninitialized scalar variable")
> Fixes: def6a7a9a7f0 ("dm space maps: improve performance with inc/dec on ranges of blocks")
> Signed-off-by: Colin Ian King <colin.king@...onical.com>
> ---
>  drivers/md/persistent-data/dm-space-map-metadata.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/md/persistent-data/dm-space-map-metadata.c b/drivers/md/persistent-data/dm-space-map-metadata.c
> index 3b70ee861cf5..5be5ef4c831f 100644
> --- a/drivers/md/persistent-data/dm-space-map-metadata.c
> +++ b/drivers/md/persistent-data/dm-space-map-metadata.c
> @@ -432,9 +432,10 @@ static int sm_metadata_dec_blocks(struct dm_space_map *sm, dm_block_t b, dm_bloc
>  	int32_t nr_allocations;
>  	struct sm_metadata *smm = container_of(sm, struct sm_metadata, sm);
>  
> -	if (recursing(smm))
> +	if (recursing(smm)) {
>  		r = add_bop(smm, BOP_DEC, b, e);
> -	else {
> +		r2 = 0;
> +	} else {
>  		in(smm);
>  		r = sm_ll_dec(&smm->ll, b, e, &nr_allocations);
>  		r2 = out(smm);
> 

There is a another occurrence of this, I'll send a V2 shortly