From: Don Zickus <dzickus@redhat.com>
To: HATAYAMA Daisuke <d.hatayama@gmail.com>
Cc: linux-tip-commits@vger.kernel.org,
Yinghai Lu <yinghai@kernel.org>,
mingo@elte.hu, kexec@lists.infradead.org,
linux-kernel@vger.kernel.org,
"d.hatayama" <d.hatayama@jp.fujitsu.com>,
mingo@redhat.com, "Eric W. Biederman" <ebiederm@xmission.com>,
hpa@zytor.com, akpm@linux-foundation.org,
torvalds@linux-foundation.org, tglx@linutronix.de,
vgoyal@redhat.com
Subject: Re: [tip:x86/debug] x86/kdump: No need to disable ioapic/ lapic in crash path
Date: Fri, 17 Feb 2012 15:18:42 -0500 [thread overview]
Message-ID: <20120217201842.GP9751@redhat.com> (raw)
In-Reply-To: <CABOkKT21zhyMwMmbR9WTipk5e=y_qMZ8ByG=njatjKbFLZW+xQ@mail.gmail.com>
On Sat, Feb 18, 2012 at 12:49:16AM +0900, HATAYAMA Daisuke wrote:
> A few days ago I investigted the case where system is reseted due to
> triple fault caused by the NMI after idt is disabled in
> machine_kexec. I didn't see the reset when trigering the kdump with
> NMI since the NMI is masked until next iret instruction executed as
> described in 6.7.2. Handling Multiple NMIs of Intel Manual Vol.3A.
> The NMI mask remains untill the first iret execution on the 2nd
> kernel: just the return path of the first kernel_thread invocation for
> init process. The exact path is:
hmm. So even though the local apic was disabled you still got an NMI?
That could have been from an external NMI. I forget how that is wired up,
if it goes through the IOAPIC to the Local APIC or directly to the NMI pin
on the cpu.
>
> switch_to
> -> ret_from_fork
> -> int_ret_from_sys_call
> -> retint_restore_args
> -> irq_return
>
> At that phase idt is already set up and kdump works.
>
> From the discussion I interpret kdump doesn't assume this behaviour,
> right?
probably not.
>
> BTW, does anyone know the detail of the NMI mask? I couldn't figure
> out about it from the Intel spec more than ``certain hardware
> conditions''... I expect those who look at here are x86 NMI experts.
I don't understand the question.
Cheers,
Don
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next prev parent reply other threads:[~2012-02-17 20:19 UTC|newest]
Thread overview: 64+ 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 3:13 ` Eric W. Biederman
2012-02-12 4:17 ` Yinghai Lu
2012-02-13 12:52 ` Eric W. Biederman
2012-02-13 16:51 ` Yinghai Lu
2012-02-13 18:16 ` Yinghai Lu
2012-02-16 17:27 ` Don Zickus
2012-02-16 21:53 ` Yinghai Lu
2012-02-16 21:56 ` Don Zickus
2012-02-17 3:38 ` Eric W. Biederman
2012-02-17 12:41 ` Eric W. Biederman
2012-02-17 15:49 ` HATAYAMA Daisuke
2012-02-17 20:18 ` Don Zickus [this message]
2012-02-20 5:17 ` HATAYAMA Daisuke
2012-02-20 15:24 ` Don Zickus
2012-02-17 19:54 ` Don Zickus
2012-02-18 3:21 ` Eric W. Biederman
2012-02-20 15:14 ` Don Zickus
2012-02-21 8:01 ` Eric W. Biederman
2012-02-21 13:59 ` Don Zickus
2012-02-29 23:19 ` Eric W. Biederman
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 10:56 ` [PATCH 2/2] boot: add early NMI counter Fernando Luis Vázquez Cao
2012-03-08 4:50 ` Eric W. Biederman
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 5:53 ` Fernando Luis Vázquez Cao
2012-03-08 16:35 ` Eric W. Biederman
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 9:55 ` [PATCH 2/3] boot: ignore early NMIs Fernando Luis Vázquez Cao
2012-03-09 10:01 ` [PATCH 3/3] boot: add early NMI counter Fernando Luis Vázquez Cao
2012-03-09 20:52 ` [PATCH 1/2] boot: ignore early NMIs H. Peter Anvin
2012-03-12 5:43 ` Fernando Luis Vázquez Cao
2012-03-12 5:49 ` H. Peter Anvin
2012-03-12 6:14 ` Fernando Luis Vázquez Cao
2012-03-12 13:36 ` Vivek Goyal
2012-03-12 19:02 ` Eric W. Biederman
2012-03-12 19:58 ` Vivek Goyal
2012-03-12 20:02 ` H. Peter Anvin
2012-03-12 18:40 ` H. Peter Anvin
2012-03-12 20:01 ` Eric W. Biederman
2012-03-12 20:04 ` H. Peter Anvin
2012-03-12 20:16 ` H. Peter Anvin
2012-03-13 2:11 ` Fernando Luis Vázquez Cao
2012-03-13 13:33 ` Don Zickus
2012-03-15 0:43 ` Simon Horman
2012-03-13 1:43 ` Fernando Luis Vázquez Cao
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 18:27 ` Yinghai Lu
2012-03-08 1:29 ` Fernando Luis Vázquez Cao
2012-03-09 0:59 ` HATAYAMA Daisuke
2012-03-09 2:48 ` Eric W. Biederman
2012-02-12 11:12 ` Ingo Molnar
2012-02-13 15:28 ` Don Zickus
2012-02-13 16:52 ` Yinghai Lu
2012-02-13 22:12 ` Don Zickus
2012-02-13 22:51 ` Don Zickus
2012-02-16 2:53 ` Don Zickus
2012-02-16 18:43 ` Yinghai Lu
2012-02-16 21:41 ` Don Zickus
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