linux-kernel - Re: [PATCH -tip] perf, x86: fix unknown NMIs on a Pentium4 box

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

Message-ID: <20110414195748.GO16939@redhat.com>
Date:	Thu, 14 Apr 2011 15:57:48 -0400
From:	Don Zickus <dzickus@...hat.com>
To:	Cyrill Gorcunov <gorcunov@...nvz.org>
Cc:	Ingo Molnar <mingo@...e.hu>, Lin Ming <ming.m.lin@...el.com>,
	Shaun Ruffell <sruffell@...ium.com>,
	Maciej Rutecki <maciej.rutecki@...il.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Stephane Eranian <eranian@...gle.com>,
	Robert Richter <robert.richter@....com>,
	lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH -tip] perf, x86: fix unknown NMIs on a Pentium4 box

On Thu, Apr 14, 2011 at 11:43:25PM +0400, Cyrill Gorcunov wrote:
> On 04/14/2011 10:46 PM, Ingo Molnar wrote:
> > 
> > btw., the bug went away once i removed your patch so it's 100% sure caused by 
> > this change.
> > 
> > Thanks,
> > 
> > 	Ingo
> 
> Ingo if you have a chance mind to give this patch a shot please? Seems we might miss unmasking
> for inflight nmis.

I don't think this patch will work.  It would make sense if the unmasking
happened _after_ the "if (!handled)" path, but that is not the path Ingo
wanted for v1.

Cheers,
Don

> -	apic_write(APIC_LVTPC, APIC_DM_NMI);
> 
>  	handled = x86_pmu.handle_irq(args->regs);
> +	apic_write(APIC_LVTPC, APIC_DM_NMI);

^^^^ all handled/unhandled NMIs hit that apic_write
>  	if (!handled)
>  		return NOTIFY_DONE;
> 
--
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/