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Date:   Tue, 25 Sep 2018 13:25:14 +0200
From:   Petr Mladek <pmladek@suse.com>
To:     zhe.he@windriver.com
Cc:     sergey.senozhatsky@gmail.com, rostedt@goodmis.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/2] printk: Fix panic caused by passing log_buf_len
 to command line
Message-ID: <20180925112514.vpxu6ldy3r4hglj6@pathway.suse.cz>
References: <1537630852-247674-1-git-send-email-zhe.he@windriver.com>
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On Sat 2018-09-22 23:40:51, zhe.he@windriver.com wrote:
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> index 9bf5404..d9821c0 100644
> --- a/kernel/printk/printk.c
> +++ b/kernel/printk/printk.c
> @@ -1048,7 +1048,14 @@ static void __init log_buf_len_update(unsigned size)
>  /* save requested log_buf_len since it's too early to process it */
>  static int __init log_buf_len_setup(char *str)
>  {
> -	unsigned size = memparse(str, &str);
> +	unsigned int size;
> +
> +	if (!str) {
> +		pr_err("boot command line parameter value not provided\n");

This message is too generic. It would be hard to guess what parameter was
affected. Also it is not fatal, so I would just use warning,
something like:

pr_warn("Warning: No value defined for the command line parameter: log_bug_len\n");

> +		return -EINVAL;
> +	}
> +
> +	size = memparse(str, &str);
>  
>  	log_buf_len_update(size);

Best Regards,
Petr