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Message-ID: <ee7bb35d-aa28-48b0-9877-c6d0881dbe64@kernel.org>
Date:   Mon, 9 Jan 2023 18:35:12 +0800
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Subject: Re: [PATCH v2] erofs/zmap.c: Fix incorrect offset calculation
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To:     Siddh Raman Pant <code@siddh.me>,
        Gao Xiang <hsiangkao@linux.alibaba.com>,
        Yue Hu <huyue2@coolpad.com>,
        Jeffle Xu <jefflexu@linux.alibaba.com>
Cc:     linux-erofs <linux-erofs@lists.ozlabs.org>,
        linux-kernel <linux-kernel@vger.kernel.org>,
        syzbot+a8e049cd3abd342936b6@syzkaller.appspotmail.com
References: <20221209102151.311049-1-code@siddh.me>
From:   Chao Yu <chao@kernel.org>
In-Reply-To: <20221209102151.311049-1-code@siddh.me>
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On 2022/12/9 18:21, Siddh Raman Pant wrote:
> Effective offset to add to length was being incorrectly calculated,
> which resulted in iomap->length being set to 0, triggering a WARN_ON
> in iomap_iter_done().
> 
> Fix that, and describe it in comments.
> 
> This was reported as a crash by syzbot under an issue about a warning
> encountered in iomap_iter_done(), but unrelated to erofs.
> 
> C reproducer: https://syzkaller.appspot.com/text?tag=ReproC&x=1037a6b2880000
> Kernel config: https://syzkaller.appspot.com/text?tag=KernelConfig&x=e2021a61197ebe02
> Dashboard link: https://syzkaller.appspot.com/bug?extid=a8e049cd3abd342936b6
> 
> Reported-by: syzbot+a8e049cd3abd342936b6@syzkaller.appspotmail.com
> Suggested-by: Gao Xiang <hsiangkao@linux.alibaba.com>
> Signed-off-by: Siddh Raman Pant <code@siddh.me>

Reviewed-by: Chao Yu <chao@kernel.org>

Thanks,