From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: zhe.he@windriver.com, sergey.senozhatsky@gmail.com,
rostedt@goodmis.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5 4/4] printk: Give error on attempt to set log buffer length to over 4G
Date: Mon, 8 Oct 2018 23:59:50 +0900 [thread overview]
Message-ID: <20181008145950.GA1473@tigerII.localdomain> (raw)
In-Reply-To: <20181008135916.gg4kkmoki5bgtco5@pathway.suse.cz>
On (10/08/18 15:59), 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.
Yeah, I think we gonna have problems even with a 4G logbuf and a 32-bit
user-space doing syslog(int len).
I agree on the "not motivated enough" part ;)
-ss
next prev parent reply other threads:[~2018-10-08 14:59 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-29 16:45 [PATCH v5 1/4] printk: Fix panic caused by passing log_buf_len to command line zhe.he
2018-09-29 16:45 ` [PATCH v5 2/4] printk: Correct wrong casting zhe.he
2018-10-02 5:50 ` Sergey Senozhatsky
2018-10-08 13:03 ` Petr Mladek
2018-09-29 16:45 ` [PATCH v5 3/4] printk: Add KBUILD_MODNAME and remove a redundant print prefix zhe.he
2018-10-02 5:52 ` Sergey Senozhatsky
2018-10-08 13:04 ` Petr Mladek
2018-09-29 16:45 ` [PATCH v5 4/4] printk: Give error on attempt to set log buffer length to over 4G zhe.he
2018-10-02 5:51 ` Sergey Senozhatsky
2018-10-08 13:59 ` Petr Mladek
2018-10-08 14:59 ` Sergey Senozhatsky [this message]
2018-10-09 13:05 ` Petr Mladek
2018-10-09 13:57 ` Sergey Senozhatsky
2018-10-10 8:09 ` Petr Mladek
2018-10-10 8:21 ` Sergey Senozhatsky
2018-10-08 16:30 ` He Zhe
2018-10-02 5:48 ` [PATCH v5 1/4] printk: Fix panic caused by passing log_buf_len to command line Sergey Senozhatsky
2018-10-08 13:01 ` Petr Mladek
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