linux-kernel - Re: [PATCH v5 4/4] printk: Give error on attempt to set log buffer length to over 4G

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Message-ID: <2a9ea0e6-f1df-7dcd-e2e8-383e297ccc5f@windriver.com>
Date:   Tue, 9 Oct 2018 00:30:12 +0800
From:   He Zhe <zhe.he@...driver.com>
To:     Petr Mladek <pmladek@...e.com>
CC:     <sergey.senozhatsky@...il.com>, <rostedt@...dmis.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 4/4] printk: Give error on attempt to set log buffer
 length to over 4G



On 2018年10月08日 21:59, Petr Mladek wrote:
> I tried this patch with log_buf_len=5G. The kernel did not crash
> but dmesg shown some mess. There are several 32-bit variables
> to store the size, for example:
>
> static u32 log_buf_len = __LOG_BUF_LEN;
> u32 log_buf_len_get(void)
> static u32 log_first_idx;
> static u32 log_next_idx;
>
> I guess that the code somewhere does not detect an overflows
> correctly.
>
> I am not motivated enought to add support for such huge message
> buffer. Therefore I suggest to limit it to 32G for now.

I'm also fine with this suggestion. Thanks.

Zhe