linux-kernel - Re: [V2 PATCH 0/6] x86, NMI: give NMI handler a face-lift

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 for Android: free password hash cracker in your pocket

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

Message-ID: <20101118143232.GC18100@redhat.com>
Date:	Thu, 18 Nov 2010 09:32:32 -0500
From:	Don Zickus <dzickus@...hat.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Jason Wessel <jason.wessel@...driver.com>,
	Ingo Molnar <mingo@...e.hu>,
	Robert Richter <robert.richter@....com>, ying.huang@...el.com,
	Andi Kleen <andi@...stfloor.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>, gorcunov@...il.com
Subject: Re: [V2 PATCH 0/6] x86, NMI: give NMI handler a face-lift

On Thu, Nov 18, 2010 at 02:17:12PM +0100, Peter Zijlstra wrote:
> On Thu, 2010-11-18 at 06:47 -0600, Jason Wessel wrote:
> > More specifically
> > when another subsystem injects an NMI event the perf NMI code returns
> > NOTIFY_STOP. 
> 
> Not unconditionally, right? We only do so when the previous NMI was from
> the PMU and nobody claimed this one (NOTIFY_STOP from DIE_NMIUNKNOWN).
> 
> Or are you hitting the other one, where !handled but pmu_nmi.handled >
> 1 ?

On my Nehalem box, the kgdb tests work fine, no issues there.  On my P4
box, the p4 handler really thinks the NMIs are from the perf counter and
returns handled==1 and starves the kgdb tests.

I haven't gotten around to checking Jason's kvm setup to determine which
handler his setup is calling.

Jason, could you snip part of your dmesg log that shows the output with
"Performance Events:" (or just send me the whole thing :-) ).

Cheers,
Don

--
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/