linux-kernel - Re: [PATCH][next] erofs: fix uninitialized variable i used in a while-loop

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Message-ID: <20210406235401.GA210667@xiangao.remote.csb>
Date:   Wed, 7 Apr 2021 07:54:01 +0800
From:   Gao Xiang <hsiangkao@...hat.com>
To:     Colin King <colin.king@...onical.com>
Cc:     Gao Xiang <xiang@...nel.org>, Chao Yu <chao@...nel.org>,
        linux-erofs@...ts.ozlabs.org, kernel-janitors@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH][next] erofs: fix uninitialized variable i used in a
 while-loop

Hi Colin,

On Tue, Apr 06, 2021 at 05:27:18PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king@...onical.com>
> 
> The while-loop iterates until src is non-null or i is 3, however, the
> loop counter i is not intinitialied to zero, causing incorrect iteration
> counts.  Fix this by initializing it to zero.
> 
> Addresses-Coverity: ("Uninitialized scalar variable")
> Fixes: 1aa5f2e2feed ("erofs: support decompress big pcluster for lz4 backend")
> Signed-off-by: Colin Ian King <colin.king@...onical.com>

Thank you very much for catching this! It looks good to me,
Reviewed-by: Gao Xiang <hsiangkao@...hat.com>

(btw, may I fold this into the original patchset? since such big pcluster
 patchset is just applied to for-next for further integration testing, and
 the commit id is not stable yet..)

Thanks,
Gao Xiang

> ---
>  fs/erofs/decompressor.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/fs/erofs/decompressor.c b/fs/erofs/decompressor.c
> index fe46a9c34923..8687ff81406b 100644
> --- a/fs/erofs/decompressor.c
> +++ b/fs/erofs/decompressor.c
> @@ -154,6 +154,7 @@ static void *z_erofs_handle_inplace_io(struct z_erofs_decompress_req *rq,
>  	}
>  	kunmap_atomic(inpage);
>  	might_sleep();
> +	i = 0;
>  	while (1) {
>  		src = vm_map_ram(rq->in, nrpages_in, -1);
>  		/* retry two more times (totally 3 times) */
> -- 
> 2.30.2
>