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Date:   Tue, 23 Aug 2022 16:42:11 +0100
From:   Matthew Wilcox <willy@infradead.org>
To:     Siddh Raman Pant <code@siddh.me>
Cc:     david@fromorbit.com, djwong@kernel.org, fgheet255t@gmail.com,
        hch@infradead.org, linux-ext4@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-xfs@vger.kernel.org, riteshh@linux.ibm.com,
        syzbot+a8e049cd3abd342936b6@syzkaller.appspotmail.com,
        syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] WARNING in iomap_iter
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References: <YwTyO0yZmUT1MVZW@casper.infradead.org>
 <20220823153542.177799-1-code@siddh.me>
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On Tue, Aug 23, 2022 at 09:05:42PM +0530, Siddh Raman Pant wrote:
> Oof, I didn't mean it to be there. That would actually be wrong anyways.
> 
> Extremely sorry for the avoidable oversight,
> Siddh
> 
> #syz test https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>

> ---
>  drivers/block/loop.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index e3c0ba93c1a3..e1fe8eda020f 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -979,6 +979,11 @@ loop_set_status_from_info(struct loop_device *lo,
>  
>  	lo->lo_offset = info->lo_offset;
>  	lo->lo_sizelimit = info->lo_sizelimit;
> +
> +	/* loff_t vars have been assigned __u64 */
> +	if (lo->lo_offset < 0 || lo->lo_sizelimit < 0)
> +		return -EOVERFLOW;
> +
>  	memcpy(lo->lo_file_name, info->lo_file_name, LO_NAME_SIZE);
>  	lo->lo_file_name[LO_NAME_SIZE-1] = 0;
>  	lo->lo_flags = info->lo_flags;
> -- 
> 2.35.1
> 
>