linux-kernel - Re: [patch 2/2] x86: mce: Implement cmci poll mode for intel machines

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <4FD020B0.5040608@linux.intel.com>
Date:	Thu, 07 Jun 2012 11:32:00 +0800
From:	Chen Gong <gong.chen@...ux.intel.com>
To:	Thomas Gleixner <tglx@...utronix.de>
CC:	LKML <linux-kernel@...r.kernel.org>, tony.luck@...el.com,
	bp@...64.org, x86@...nel.org, Peter Zijlstra <peterz@...radead.org>
Subject: Re: [patch 2/2] x86: mce: Implement cmci poll mode for intel machines

于 2012/6/6 22:46, Thomas Gleixner 写道:
> On Wed, 6 Jun 2012, Thomas Gleixner wrote:
>
>> On Wed, 6 Jun 2012, Chen Gong wrote:
>>> 于 2012/6/6 18:23, Thomas Gleixner 写道:
>>> I think you mean
>>>
>>> -               del_timer_sync(t);
>>>                  smp_call_function_single(cpu, mce_disable_cpu,&action, 1);
>>> +		del_timer_sync(t);
>>>                  break;
>>
>> No I meant it the way I wrote, but as you don't execute hotplug it's
>> irrelevant.
>>
>> So the obvious candidate is the mce-injection code, which was
>> obviously never tested with DEBUG_PREEMPT enabled.
>>
>> raise_local() can be called with preemption enabled from
>> raise_mce(). Fix for that below.
>>
>> Though I can't see how that would do anything with the timer.
>
> I think I found it. Do you have CONFIG_NO_HZ enabled? Then mod_timer()
> will try to move the timer to a different cpu, when the cpu which is
> running that code is idle. Bloody obvious :(

Oh, yes, it works! mod_timer is really a naughty baby :-).
Now it passes the basic test, and then I will use your latest
patch series to test more scenarios.

>
> I'll send out a combo patch with all changes so far later.
>
> Thanks,
> 	
> 	tglx
>
> Index: linux-2.6/arch/x86/kernel/cpu/mcheck/mce.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/cpu/mcheck/mce.c
> +++ linux-2.6/arch/x86/kernel/cpu/mcheck/mce.c
> @@ -1307,7 +1307,7 @@ void mce_timer_kick(unsigned long interv
>
>   	if (timer_pending(t)) {
>   		if (time_before(when, t->expires))
> -			mod_timer(t, when);
> +			mod_timer_pinned(t, when);
>   	} else {
>   		t->expires = round_jiffies(when);
>   		add_timer_on(t, smp_processor_id());

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/