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Date:   Tue, 11 Jul 2023 22:13:06 +0800
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Subject: Re: [PATCH] erofs: fix to avoid infinite loop in
 z_erofs_do_read_page() when read page beyond EOF
Content-Language: en-US
To:     Chunhai Guo <guochunhai@vivo.com>, xiang@kernel.org
Cc:     huyue2@coolpad.com, jefflexu@linux.alibaba.com,
        linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org
References: <20230710093410.44071-1-guochunhai@vivo.com>
From:   Chao Yu <chao@kernel.org>
In-Reply-To: <20230710093410.44071-1-guochunhai@vivo.com>
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On 2023/7/10 17:34, Chunhai Guo wrote:
> z_erofs_do_read_page() may loop infinitely due to the inappropriate
> truncation in the below statement. Since the offset is 64 bits and min_t()
> truncates the result to 32 bits. The solution is to replace unsigned int
> with a 64-bit type, such as erofs_off_t.
>      cur = end - min_t(unsigned int, offset + end - map->m_la, end);
> 
>      - For example:
>          - offset = 0x400160000
>          - end = 0x370
>          - map->m_la = 0x160370
>          - offset + end - map->m_la = 0x400000000
>          - offset + end - map->m_la = 0x00000000 (truncated as unsigned int)
>      - Expected result:
>          - cur = 0
>      - Actual result:
>          - cur = 0x370
> 
> Signed-off-by: Chunhai Guo <guochunhai@vivo.com>

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

Thanks,