linux-kernel - Re: [PATCH 08/13] x86: do not use print

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Message-ID: <20171211174459.l2ugmyi6kcr33zxp@pd.tnic>
Date:   Mon, 11 Dec 2017 18:45:00 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Russell King <linux@...linux.org.uk>,
        Catalin Marinas <catalin.marinas@....com>,
        Mark Salter <msalter@...hat.com>,
        Tony Luck <tony.luck@...el.com>,
        David Howells <dhowells@...hat.com>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Guan Xuetao <gxt@...c.pku.edu.cn>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Vineet Gupta <vgupta@...opsys.com>,
        Fengguang Wu <fengguang.wu@...el.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Petr Mladek <pmladek@...e.com>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-arm-kernel@...ts.infradead.org, linux-c6x-dev@...ux-c6x.org,
        linux-ia64@...r.kernel.org, linux-am33-list@...hat.com,
        linux-sh@...r.kernel.org, linux-edac@...r.kernel.org,
        x86@...nel.org, linux-snps-arc@...ts.infradead.org,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Subject: Re: [PATCH 08/13] x86: do not use print_symbol()

On Mon, Dec 11, 2017 at 09:50:20PM +0900, Sergey Senozhatsky wrote:
> print_symbol() uses extra stack space to sprintf() symbol
> information and then to feed that buffer to printk()
> 
>   char buffer[KSYM_SYMBOL_LEN];
> 
>   sprint_symbol(buffer, address);
>   printk(fmt, buffer);
> 
> Replace print_symbol() with a direct printk("%pS") call.
> 
> Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
> Cc: Tony Luck <tony.luck@...el.com>
> Cc: Borislav Petkov <bp@...en8.de>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> ---
>  arch/x86/kernel/cpu/mcheck/mce.c | 3 +--
>  arch/x86/mm/mmio-mod.c           | 5 ++---
>  2 files changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index b1d616d08eee..8ca8f6eb32db 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -14,7 +14,6 @@
>  #include <linux/capability.h>
>  #include <linux/miscdevice.h>
>  #include <linux/ratelimit.h>
> -#include <linux/kallsyms.h>
>  #include <linux/rcupdate.h>
>  #include <linux/kobject.h>
>  #include <linux/uaccess.h>
> @@ -235,7 +234,7 @@ static void __print_mce(struct mce *m)
>  			m->cs, m->ip);
>  
>  		if (m->cs == __KERNEL_CS)
> -			print_symbol("{%s}", m->ip);
> +			pr_cont("{%pS}", (void *)m->ip);
>  		pr_cont("\n");
>  	}
>  

For the mce.c bit above:

Acked-by: Borislav Petkov <bp@...e.de>

Thx.

-- 
Regards/Gruss,
    Boris.

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