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Date:   Thu, 18 Aug 2022 15:50:02 +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: <20220818110031.89467-1-code@siddh.me>
 <20220818111117.102681-1-code@siddh.me>
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On Thu, Aug 18, 2022 at 04:41:17PM +0530, Siddh Raman Pant wrote:
>  include/uapi/linux/loop.h | 12 ++++++------

I don't think changing these from u64 to s64 is the right way to go.

>  2 files changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/block/loop.c b/drivers/block/loop.c
> index e3c0ba93c1a3..4ca20ce3158d 100644
> --- a/drivers/block/loop.c
> +++ b/drivers/block/loop.c
> @@ -977,6 +977,9 @@ loop_set_status_from_info(struct loop_device *lo,
>  		return -EINVAL;
>  	}
>  
> +	if (info->lo_offset < 0 || info->lo_sizelimit < 0)
> +		return -EINVAL;
> +
>  	lo->lo_offset = info->lo_offset;
>  	lo->lo_sizelimit = info->lo_sizelimit;

I'd instead do it here:

	if (lo>lo_offset < 0 || lo->lo_sizelimit < 0)
		return -EINVAL;