From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
zhe.he@windriver.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: Tue, 9 Oct 2018 22:57:58 +0900 [thread overview]
Message-ID: <20181009135758.GA1419@tigerII.localdomain> (raw)
In-Reply-To: <20181009130538.7rtd3du2d7l6m63w@pathway.suse.cz>
On (10/09/18 15:05), Petr Mladek wrote:
> >
> > 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 ;)
>
> OK, I have pushed an updated patch that has the limit 2GB
> into printk.git, for-4.20 branch.
>
> Note that it is slightly different than the yesterday's proposal.
> I made a mistake in testing and still compared with UNIT_MAX.
>
> The pushed version can be seen at
> https://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk.git/commit/?h=for-4.20&id=e6fe3e5b7d16e8f146a4ae7fe481bc6e97acde1e
---
> +#define LOG_BUF_LEN_MAX (u32)(1 << 31)
[..]
> + if (size > (u64)LOG_BUF_LEN_MAX) {
> + size = (u64)LOG_BUF_LEN_MAX;
> + pr_err("log_buf over 2G is not supported.\n");
> + }
Why not INT_MAX?
> + pr_info("log_buf_len: %u bytes\n", log_buf_len);
> + pr_info("early log buf free: %u(%u%%)\n",
> free, (free * 100) / __LOG_BUF_LEN);
Can 'free * 100' overflow?
-ss
next prev parent reply other threads:[~2018-10-09 13:58 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
2018-10-09 13:05 ` Petr Mladek
2018-10-09 13:57 ` Sergey Senozhatsky [this message]
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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