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From: Peter Zijlstra <peterz@infradead.org>
To: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: x86@kernel.org, Jonathan Corbet <corbet@lwn.net>,
	linux-doc@vger.kernel.org, kexec@lists.infradead.org,
	linux-kernel@vger.kernel.org, Michal Hocko <mhocko@kernel.org>,
	Ingo Molnar <mingo@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Ingo Molnar <mingo@kernel.org>, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [V3 PATCH 2/4] panic/x86: Allow cpus to save registers even if they are looping in NMI context
Date: Fri, 21 Aug 2015 01:18:16 +0200	[thread overview]
Message-ID: <20150820231816.GH3161@worktop.event.rightround.com> (raw)
In-Reply-To: <20150806054543.25766.5526.stgit@softrs>

On Thu, Aug 06, 2015 at 02:45:43PM +0900, Hidehiro Kawai wrote:
> When cpu-A panics on NMI just after cpu-B has panicked, cpu-A loops
> infinitely in NMI context.  Especially for x86, cpu-B issues NMI IPI
> to other cpus to save their register states and do some cleanups if
> kdump is enabled, but cpu-A can't handle the NMI and fails to save
> register states.
> 
> To solve thie issue, we wait for the timing of the NMI IPI, then
> call the NMI handler which saves register states.

Sorry, I don't follow, what?

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WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <peterz@infradead.org>
To: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Cc: Jonathan Corbet <corbet@lwn.net>, Ingo Molnar <mingo@kernel.org>,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Vivek Goyal <vgoyal@redhat.com>,
	linux-doc@vger.kernel.org, x86@kernel.org,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	Michal Hocko <mhocko@kernel.org>, Ingo Molnar <mingo@redhat.com>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Subject: Re: [V3 PATCH 2/4] panic/x86: Allow cpus to save registers even if they are looping in NMI context
Date: Fri, 21 Aug 2015 01:18:16 +0200	[thread overview]
Message-ID: <20150820231816.GH3161@worktop.event.rightround.com> (raw)
In-Reply-To: <20150806054543.25766.5526.stgit@softrs>

On Thu, Aug 06, 2015 at 02:45:43PM +0900, Hidehiro Kawai wrote:
> When cpu-A panics on NMI just after cpu-B has panicked, cpu-A loops
> infinitely in NMI context.  Especially for x86, cpu-B issues NMI IPI
> to other cpus to save their register states and do some cleanups if
> kdump is enabled, but cpu-A can't handle the NMI and fails to save
> register states.
> 
> To solve thie issue, we wait for the timing of the NMI IPI, then
> call the NMI handler which saves register states.

Sorry, I don't follow, what?

  reply	other threads:[~2015-08-20 23:18 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-08-06  5:45 [V3 PATCH 0/4] Fix race issues among panic, NMI and crash_kexec Hidehiro Kawai
2015-08-06  5:45 ` Hidehiro Kawai
2015-08-06  5:45 ` [V3 PATCH 4/4] x86/apic: Introduce noextnmi boot option Hidehiro Kawai
2015-08-06  5:45   ` Hidehiro Kawai
2015-08-06  5:45 ` [V3 PATCH 3/4] kexec: Fix race between panic() and crash_kexec() called directly Hidehiro Kawai
2015-08-06  5:45   ` Hidehiro Kawai
2015-08-20 23:08   ` Peter Zijlstra
2015-08-20 23:08     ` Peter Zijlstra
2015-08-22  2:35     ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-22  2:35       ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-25 14:52       ` Peter Zijlstra
2015-08-25 14:52         ` Peter Zijlstra
2015-08-26  3:11         ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-26  3:11           ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-31  8:53           ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-31  8:53             ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-31  9:07             ` Peter Zijlstra
2015-08-31  9:07               ` Peter Zijlstra
2015-08-31  9:57               ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-31  9:57                 ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-06  5:45 ` [V3 PATCH 1/4] panic/x86: Fix re-entrance problem due to panic on NMI Hidehiro Kawai
2015-08-06  5:45   ` Hidehiro Kawai
2015-08-20 23:45   ` Peter Zijlstra
2015-08-20 23:45     ` Peter Zijlstra
2015-08-22  0:46     ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-22  0:46       ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-06  5:45 ` [V3 PATCH 2/4] panic/x86: Allow cpus to save registers even if they are looping in NMI context Hidehiro Kawai
2015-08-06  5:45   ` Hidehiro Kawai
2015-08-20 23:18   ` Peter Zijlstra [this message]
2015-08-20 23:18     ` Peter Zijlstra
2015-08-22  1:43     ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-22  1:43       ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-07 14:38 ` [V3 PATCH 0/4] Fix race issues among panic, NMI and crash_kexec Michal Hocko
2015-08-07 14:38   ` Michal Hocko
2015-08-20 23:17 ` Peter Zijlstra
2015-08-20 23:17   ` Peter Zijlstra
2015-08-22  0:41   ` 河合英宏 / KAWAI,HIDEHIRO
2015-08-22  0:41     ` 河合英宏 / KAWAI,HIDEHIRO

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