From: "H. Peter Anvin" <hpa@zytor.com>
To: "Fernando Luis Vázquez Cao" <fernando@oss.ntt.co.jp>
Cc: Don Zickus <dzickus@redhat.com>,
akpm@linux-foundation.org, linux-tip-commits@vger.kernel.org,
Yinghai Lu <yinghai@kernel.org>,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
mingo@redhat.com, "Eric W. Biederman" <ebiederm@xmission.com>,
tglx@linutronix.de, torvalds@linux-foundation.org, mingo@elte.hu,
vgoyal@redhat.com
Subject: Re: [PATCH 1/2] boot: ignore early NMIs
Date: Sun, 11 Mar 2012 22:49:23 -0700 [thread overview]
Message-ID: <4F5D8E63.60606@zytor.com> (raw)
In-Reply-To: <4F5D8D0E.8060702@oss.ntt.co.jp>
On 03/11/2012 10:43 PM, Fernando Luis Vázquez Cao wrote:
>
> To tackle this issue we can either stop the hardlockup detector
> or disable the LAPIC (the NMIs needed by x86's hardlockup detector
> are generated using performance counters in the LAPIC), leaving
> the I/O APICs untouched. The second is simpler and I think it
> is the approach Don took to fix this issue in RHEL kernels.
>
> Unfortunately, this is not enough, we are still exposed to external
> NMIs not routed through the LAPIC. In other words, we have to make
> sure that we always have and IDT that is able to handle NMIs without
> seemingly random reboots and lockups. To achieve this goal we need
> to fix machine_kexec() and the early IDT handlers. The current patch
> set takes care of the latter.
>
The only source of NMIs other than the LAPIC should be the system error
which can be disabled through the RTC port, so I think your second
paragraph here is way more mechanism than you need for very little gain.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
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WARNING: multiple messages have this Message-ID (diff)
From: "H. Peter Anvin" <hpa@zytor.com>
To: "Fernando Luis Vázquez Cao" <fernando@oss.ntt.co.jp>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Don Zickus <dzickus@redhat.com>,
linux-tip-commits@vger.kernel.org, torvalds@linux-foundation.org,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
mingo@redhat.com, tglx@linutronix.de, mingo@elte.hu,
Yinghai Lu <yinghai@kernel.org>,
akpm@linux-foundation.org, vgoyal@redhat.com
Subject: Re: [PATCH 1/2] boot: ignore early NMIs
Date: Sun, 11 Mar 2012 22:49:23 -0700 [thread overview]
Message-ID: <4F5D8E63.60606@zytor.com> (raw)
In-Reply-To: <4F5D8D0E.8060702@oss.ntt.co.jp>
On 03/11/2012 10:43 PM, Fernando Luis Vázquez Cao wrote:
>
> To tackle this issue we can either stop the hardlockup detector
> or disable the LAPIC (the NMIs needed by x86's hardlockup detector
> are generated using performance counters in the LAPIC), leaving
> the I/O APICs untouched. The second is simpler and I think it
> is the approach Don took to fix this issue in RHEL kernels.
>
> Unfortunately, this is not enough, we are still exposed to external
> NMIs not routed through the LAPIC. In other words, we have to make
> sure that we always have and IDT that is able to handle NMIs without
> seemingly random reboots and lockups. To achieve this goal we need
> to fix machine_kexec() and the early IDT handlers. The current patch
> set takes care of the latter.
>
The only source of NMIs other than the LAPIC should be the system error
which can be disabled through the RTC port, so I think your second
paragraph here is way more mechanism than you need for very little gain.
-hpa
--
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel. I don't speak on their behalf.
next prev parent reply other threads:[~2012-03-12 5:50 UTC|newest]
Thread overview: 127+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-11 23:09 [tip:x86/debug] x86/kdump: No need to disable ioapic/ lapic in crash path tip-bot for Don Zickus
2012-02-12 1:04 ` Yinghai Lu
2012-02-12 1:04 ` Yinghai Lu
2012-02-12 3:13 ` Eric W. Biederman
2012-02-12 3:13 ` Eric W. Biederman
2012-02-12 4:17 ` Yinghai Lu
2012-02-12 4:17 ` Yinghai Lu
2012-02-13 12:52 ` Eric W. Biederman
2012-02-13 12:52 ` Eric W. Biederman
2012-02-13 16:51 ` Yinghai Lu
2012-02-13 16:51 ` Yinghai Lu
2012-02-13 18:16 ` Yinghai Lu
2012-02-13 18:16 ` Yinghai Lu
2012-02-16 17:27 ` Don Zickus
2012-02-16 17:27 ` Don Zickus
2012-02-16 21:53 ` Yinghai Lu
2012-02-16 21:53 ` Yinghai Lu
2012-02-16 21:56 ` Don Zickus
2012-02-16 21:56 ` Don Zickus
2012-02-17 3:38 ` Eric W. Biederman
2012-02-17 3:38 ` Eric W. Biederman
2012-02-17 12:41 ` Eric W. Biederman
2012-02-17 12:41 ` Eric W. Biederman
2012-02-17 15:49 ` HATAYAMA Daisuke
2012-02-17 15:49 ` HATAYAMA Daisuke
2012-02-17 20:18 ` Don Zickus
2012-02-17 20:18 ` Don Zickus
2012-02-20 5:17 ` HATAYAMA Daisuke
2012-02-20 5:17 ` HATAYAMA Daisuke
2012-02-20 15:24 ` Don Zickus
2012-02-20 15:24 ` Don Zickus
2012-02-17 19:54 ` Don Zickus
2012-02-17 19:54 ` Don Zickus
2012-02-18 3:21 ` Eric W. Biederman
2012-02-18 3:21 ` Eric W. Biederman
2012-02-20 15:14 ` Don Zickus
2012-02-20 15:14 ` Don Zickus
2012-02-21 8:01 ` Eric W. Biederman
2012-02-21 8:01 ` Eric W. Biederman
2012-02-21 13:59 ` Don Zickus
2012-02-21 13:59 ` Don Zickus
2012-02-29 23:19 ` Eric W. Biederman
2012-02-29 23:19 ` Eric W. Biederman
2012-03-07 10:53 ` Fernando Luis Vázquez Cao
2012-03-07 10:53 ` Fernando Luis Vázquez Cao
2012-03-07 10:54 ` [PATCH 1/2] boot: ignore early NMIs Fernando Luis Vázquez Cao
2012-03-07 10:54 ` Fernando Luis Vázquez Cao
2012-03-07 10:56 ` [PATCH 2/2] boot: add early NMI counter Fernando Luis Vázquez Cao
2012-03-07 10:56 ` Fernando Luis Vázquez Cao
2012-03-08 4:50 ` Eric W. Biederman
2012-03-08 4:50 ` Eric W. Biederman
2012-03-08 6:00 ` Fernando Luis Vázquez Cao
2012-03-08 6:00 ` Fernando Luis Vázquez Cao
2012-03-08 4:41 ` [PATCH 1/2] boot: ignore early NMIs Eric W. Biederman
2012-03-08 4:41 ` Eric W. Biederman
2012-03-08 5:53 ` Fernando Luis Vázquez Cao
2012-03-08 5:53 ` Fernando Luis Vázquez Cao
2012-03-08 16:35 ` Eric W. Biederman
2012-03-08 16:35 ` Eric W. Biederman
2012-03-09 9:31 ` Fernando Luis Vázquez Cao
2012-03-09 9:31 ` Fernando Luis Vázquez Cao
2012-03-09 9:51 ` [PATCH 1/3] boot: fortify early_idt_handlers definition Fernando Luis Vázquez Cao
2012-03-09 9:51 ` Fernando Luis Vázquez Cao
2012-03-09 9:55 ` [PATCH 2/3] boot: ignore early NMIs Fernando Luis Vázquez Cao
2012-03-09 9:55 ` Fernando Luis Vázquez Cao
2012-03-09 10:01 ` [PATCH 3/3] boot: add early NMI counter Fernando Luis Vázquez Cao
2012-03-09 10:01 ` Fernando Luis Vázquez Cao
2012-03-09 20:52 ` [PATCH 1/2] boot: ignore early NMIs H. Peter Anvin
2012-03-09 20:52 ` H. Peter Anvin
2012-03-12 5:43 ` Fernando Luis Vázquez Cao
2012-03-12 5:43 ` Fernando Luis Vázquez Cao
2012-03-12 5:49 ` H. Peter Anvin [this message]
2012-03-12 5:49 ` H. Peter Anvin
2012-03-12 6:14 ` Fernando Luis Vázquez Cao
2012-03-12 6:14 ` Fernando Luis Vázquez Cao
2012-03-12 13:36 ` Vivek Goyal
2012-03-12 13:36 ` Vivek Goyal
2012-03-12 19:02 ` Eric W. Biederman
2012-03-12 19:02 ` Eric W. Biederman
2012-03-12 19:58 ` Vivek Goyal
2012-03-12 19:58 ` Vivek Goyal
2012-03-12 20:02 ` H. Peter Anvin
2012-03-12 20:02 ` H. Peter Anvin
2012-03-12 18:40 ` H. Peter Anvin
2012-03-12 18:40 ` H. Peter Anvin
2012-03-12 20:01 ` Eric W. Biederman
2012-03-12 20:01 ` Eric W. Biederman
2012-03-12 20:04 ` H. Peter Anvin
2012-03-12 20:04 ` H. Peter Anvin
2012-03-12 20:16 ` H. Peter Anvin
2012-03-12 20:16 ` H. Peter Anvin
2012-03-13 2:11 ` Fernando Luis Vázquez Cao
2012-03-13 2:11 ` Fernando Luis Vázquez Cao
2012-03-13 13:33 ` Don Zickus
2012-03-13 13:33 ` Don Zickus
2012-03-15 0:43 ` Simon Horman
2012-03-15 0:43 ` Simon Horman
2012-03-13 1:43 ` Fernando Luis Vázquez Cao
2012-03-13 1:43 ` Fernando Luis Vázquez Cao
2012-03-12 14:41 ` Don Zickus
2012-03-12 14:41 ` Don Zickus
2012-03-07 15:50 ` [tip:x86/debug] x86/kdump: No need to disable ioapic/ lapic in crash path Vivek Goyal
2012-03-07 15:50 ` Vivek Goyal
2012-03-07 18:27 ` Yinghai Lu
2012-03-07 18:27 ` Yinghai Lu
2012-03-08 1:29 ` Fernando Luis Vázquez Cao
2012-03-08 1:29 ` Fernando Luis Vázquez Cao
2012-03-09 0:59 ` HATAYAMA Daisuke
2012-03-09 0:59 ` HATAYAMA Daisuke
2012-03-09 2:48 ` Eric W. Biederman
2012-03-09 2:48 ` Eric W. Biederman
2012-02-12 11:12 ` Ingo Molnar
2012-02-12 11:12 ` Ingo Molnar
2012-02-13 15:28 ` Don Zickus
2012-02-13 15:28 ` Don Zickus
2012-02-13 16:52 ` Yinghai Lu
2012-02-13 16:52 ` Yinghai Lu
2012-02-13 22:12 ` Don Zickus
2012-02-13 22:12 ` Don Zickus
2012-02-13 22:51 ` Don Zickus
2012-02-13 22:51 ` Don Zickus
2012-02-16 2:53 ` Don Zickus
2012-02-16 2:53 ` Don Zickus
2012-02-16 18:43 ` Yinghai Lu
2012-02-16 18:43 ` Yinghai Lu
2012-02-16 21:41 ` Don Zickus
2012-02-16 21:41 ` Don Zickus
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