linux-kernel - Re: [PATCH v3 2/2] x86 mce: use new printk recursion disabling interface

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Message-ID: <20120604171202.GA8533@x1.osrc.amd.com>
Date:	Mon, 4 Jun 2012 19:12:02 +0200
From:	Borislav Petkov <bp@...en8.de>
To:	ShuoX Liu <shuox.liu@...el.com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Yanmin Zhang <yanmin_zhang@...ux.intel.com>,
	"Luck, Tony" <tony.luck@...el.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	"andi@...stfloor.org" <andi@...stfloor.org>,
	Ingo Molnar <mingo@...e.hu>
Subject: Re: [PATCH v3 2/2] x86 mce: use new printk recursion disabling
 interface

On Mon, May 28, 2012 at 10:56:04AM +0800, ShuoX Liu wrote:
> From: ShuoX Liu <shuox.liu@...el.com>
> 
> Disable printk recursion to make sure MCE logs printed out.
> 
> Signed-off-by: Yanmin Zhang <yanmin_zhang@...ux.intel.com>
> Signed-off-by: ShuoX Liu <shuox.liu@...el.com>
> ---
>  arch/x86/kernel/cpu/mcheck/mce.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
> index 2afcbd2..365c35d 100644
> --- a/arch/x86/kernel/cpu/mcheck/mce.c
> +++ b/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -1015,6 +1015,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
>  	DECLARE_BITMAP(toclear, MAX_NR_BANKS);
>  	char *msg = "Unknown";
>  
> +	printk_recursion_check_disable();
>  	atomic_inc(&mce_entry);
>  
>  	this_cpu_inc(mce_exception_count);
> @@ -1144,6 +1145,7 @@ void do_machine_check(struct pt_regs *regs, long error_code)
>  	mce_wrmsrl(MSR_IA32_MCG_STATUS, 0);
>  out:
>  	atomic_dec(&mce_entry);
> +	printk_recursion_check_enable();
>  	sync_core();

This is still adding the recursion check things in do_machine_check
instead of in print_mce.

Also, this commit message above needs more explanation why we want to
disable the recursion check on an MCE, maybe an example...

Thanks.

-- 
Regards/Gruss,
Boris.
--
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