From: Don Zickus <dzickus@redhat.com>
To: Yinghai Lu <yinghai@kernel.org>
Cc: linux-tip-commits@vger.kernel.org, mingo@elte.hu,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
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: Thu, 16 Feb 2012 12:27:35 -0500 [thread overview]
Message-ID: <20120216172735.GX9751@redhat.com> (raw)
In-Reply-To: <CAE9FiQVPnO8-tuPoio0Wxv=8rjdm2tJbBk3+3ystueyYtZn9BA@mail.gmail.com>
On Mon, Feb 13, 2012 at 10:16:00AM -0800, Yinghai Lu wrote:
> On Mon, Feb 13, 2012 at 8:51 AM, Yinghai Lu <yinghai@kernel.org> wrote:
> >> So I suspect we have a bug in our apic initialization somewhere, but
> >> apic initialization should happen after printk are enabled. Or at least
> >> after early printks so the reset YH is reporting doesn't make much sense.
> >
> > will try Don's first version patch that only removing disable_IO_APIC.
>
> first version patch (only removing disable_IO_APIC) is working.
So I think I figured it out. I went through and commented out code in
disable_local_APIC until I narrowed it down to the piece of code that
needs to be disabled for it to work.
Surprise, surprise... its LVTPC or perf! :-) Actually it is the
nmi_watchdog which uses perf. My theory is NMIs are not disabled and one
is generated by the local apic during decompression (just bad timing) and
*splat*.
Yinghai, you can probably prove this by
echo 0 > /proc/sys/kernel/nmi_watchdog
then do your kdump crash test.
At least that test worked for me.
So either we explicitly shutdown perf or just mask off LVTPC in a modified
disable_local_APIC?
Eric, thoughts, preferences?
Cheers,
Don
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next prev parent reply other threads:[~2012-02-16 19:10 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 [this message]
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
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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