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From: Don Zickus <dzickus@redhat.com>
To: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: linux-arch@vger.kernel.org, heiko.carstens@de.ibm.com,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	schwidefsky@de.ibm.com, Andrew Morton <akpm@linux-foundation.org>,
	Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH v2] kdump: Fix crash_kexec - smp_send_stop race in panic
Date: Tue, 1 Nov 2011 16:04:20 -0400	[thread overview]
Message-ID: <20111101200420.GN17705@redhat.com> (raw)
In-Reply-To: <1320064459.2796.26.camel@br98xy6r>

On Mon, Oct 31, 2011 at 01:34:19PM +0100, Michael Holzheu wrote:
> Hello Andrew, hello linux-arch,
> 
> > Well OK.  Maybe some architectures do have this problem - who would
> > notice?  If that is the case, we just made the failure cases much more
> > common.  Could you check, please?
> 
> @linux-arch: 
> 
> This patch introduces a spinlock to prevent parallel execution of the
> panic code. Andrew pointed out that this might be a problem for
> architectures that can't do smp_send_stop() on remote CPUs that have
> interrupts disabled. When irq-disabled CPUs execute panic() in parallel,
> we then would have looping CPUs.

x86 has such problem and I posted a patch recently to fix it

https://lkml.org/lkml/2011/10/13/426

Cheers,
Don

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WARNING: multiple messages have this Message-ID (diff)
From: Don Zickus <dzickus@redhat.com>
To: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	linux-arch@vger.kernel.org, heiko.carstens@de.ibm.com,
	kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
	"Eric W. Biederman" <ebiederm@xmission.com>,
	schwidefsky@de.ibm.com, Vivek Goyal <vgoyal@redhat.com>
Subject: Re: [PATCH v2] kdump: Fix crash_kexec - smp_send_stop race in panic
Date: Tue, 1 Nov 2011 16:04:20 -0400	[thread overview]
Message-ID: <20111101200420.GN17705@redhat.com> (raw)
In-Reply-To: <1320064459.2796.26.camel@br98xy6r>

On Mon, Oct 31, 2011 at 01:34:19PM +0100, Michael Holzheu wrote:
> Hello Andrew, hello linux-arch,
> 
> > Well OK.  Maybe some architectures do have this problem - who would
> > notice?  If that is the case, we just made the failure cases much more
> > common.  Could you check, please?
> 
> @linux-arch: 
> 
> This patch introduces a spinlock to prevent parallel execution of the
> panic code. Andrew pointed out that this might be a problem for
> architectures that can't do smp_send_stop() on remote CPUs that have
> interrupts disabled. When irq-disabled CPUs execute panic() in parallel,
> we then would have looping CPUs.

x86 has such problem and I posted a patch recently to fix it

https://lkml.org/lkml/2011/10/13/426

Cheers,
Don

  reply	other threads:[~2011-11-01 20:04 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-26 14:34 [PATCH] kdump: Fix crash_kexec - smp_send_stop race in panic Michael Holzheu
2011-10-26 14:34 ` Michael Holzheu
2011-10-27 17:40 ` Vivek Goyal
2011-10-27 17:40   ` Vivek Goyal
2011-10-28 23:11 ` Andrew Morton
2011-10-28 23:11   ` Andrew Morton
2011-10-31  9:57   ` Michael Holzheu
2011-10-31  9:57     ` Michael Holzheu
2011-10-31 10:39     ` Andrew Morton
2011-10-31 10:39       ` Andrew Morton
2011-10-31 12:34       ` [PATCH v2] " Michael Holzheu
2011-10-31 12:34         ` Michael Holzheu
2011-11-01 20:04         ` Don Zickus [this message]
2011-11-01 20:04           ` Don Zickus
2011-11-02 10:03           ` Michael Holzheu
2011-11-02 10:03             ` Michael Holzheu
2011-11-02 10:03             ` Michael Holzheu
2011-11-02 20:57             ` Luck, Tony
2011-11-02 20:57               ` Luck, Tony
2011-11-03 10:07       ` [PATCH] " Michael Holzheu
2011-11-03 10:07         ` Michael Holzheu
2011-11-10  0:04         ` Andrew Morton
2011-11-10  0:04           ` Andrew Morton
2011-11-10 14:17           ` Américo Wang
2011-11-10 14:17             ` Américo Wang
2011-11-10 14:22           ` Michael Holzheu
2011-11-10 14:22             ` Michael Holzheu
2011-11-10 15:11             ` Chris Metcalf
2011-11-10 15:11               ` Chris Metcalf
2011-11-11 12:28               ` Michael Holzheu
2011-11-11 12:28                 ` Michael Holzheu
2011-11-11 12:30                 ` James Bottomley
2011-11-11 12:30                   ` James Bottomley
2011-11-11 17:02                 ` Chris Metcalf
2011-11-11 17:02                   ` Chris Metcalf
2011-11-29  8:58                   ` [PATCH v3] " Michael Holzheu
2011-11-29  8:58                     ` Michael Holzheu
2011-11-11 17:45                 ` [PATCH] " Richard Kuo
2011-11-11 17:45                   ` Richard Kuo
2011-11-10 15:31           ` James Bottomley
2011-11-10 15:31             ` James Bottomley

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