Re: [RFC][PATCH] printk: Add option to append kernel version to the dict

From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Calvin Owens <calvinowens@fb.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	David Howells <dhowells@redhat.com>,
	Pranith Kumar <bobby.prani@gmail.com>,
	David Woodhouse <David.Woodhouse@intel.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Petr Mladek <pmladek@suse.com>, Tejun Heo <tj@kernel.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	Vasily Averin <vvs@virtuozzo.com>,
	Thierry Reding <treding@nvidia.com>,
	Geliang Tang <geliangtang@163.com>,
	Ivan Delalande <colona@arista.com>,
	linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [RFC][PATCH] printk: Add option to append kernel version to the dict
Date: Sun, 15 May 2016 15:36:43 +0900	[thread overview]
Message-ID: <20160515063643.GA817@swordfish> (raw)
In-Reply-To: <51047c0f6e86abcb9ee13f60653b6946f8fcfc99.1463172791.git.calvinowens@fb.com>

Hello,

On (05/13/16 13:58), Calvin Owens wrote:
[..]
> +#if defined(CONFIG_PRINTK_APPEND_UNAME)
> +static ssize_t msg_print_ext_uname(char *buf, size_t size)
> +{
> +	return scnprintf(buf, size, " UNAME=%s\n", init_utsname()->release);
> +}
> +#else
> +static ssize_t msg_print_ext_uname(char *buf, size_t size)
> +{
> +	return 0;
> +}
> +#endif
> +
>  /* /dev/kmsg - userspace message inject/listen interface */
>  struct devkmsg_user {
>  	u64 seq;
> @@ -2305,6 +2317,8 @@ skip:
>  						sizeof(ext_text) - ext_len,
>  						log_dict(msg), msg->dict_len,
>  						log_text(msg), msg->text_len);
> +			ext_len += msg_print_ext_uname(ext_text + ext_len,
> +						sizeof(ext_text) - ext_len);
>  		}

what if there is no place left for init_utsname() after msg_print_ext_header() + msg_print_ext_body()?
do you need init_utsname in every message? or just in WARN/ERR ones?

	-ss