From: Michael Holzheu <holzheu@linux.vnet.ibm.com>
To: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: "Vivek Goyal" <vgoyal@redhat.com>,
"Eric W. Biederman" <ebiederm@xmission.com>,
"Américo Wang" <xiyou.wangcong@gmail.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"schwidefsky@de.ibm.com" <schwidefsky@de.ibm.com>,
"heiko.carstens@de.ibm.com" <heiko.carstens@de.ibm.com>,
"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: kdump: crash_kexec()-smp_send_stop() race in panic
Date: Tue, 25 Oct 2011 10:33:42 +0200 [thread overview]
Message-ID: <1319531622.3056.1.camel@br98xy6r> (raw)
In-Reply-To: <5C4C569E8A4B9B42A84A977CF070A35B2C57612A37@USINDEVS01.corp.hds.com>
Hello Seiji,
On Mon, 2011-10-24 at 18:24 -0400, Seiji Aguchi wrote:
> Hi,
>
> >> >>> 1st CPU:
> >> >>> panic()->crash_kexec()->mutex_trylock(&kexec_mutex)-> do kdump
> >> >>>
> >> >>> 2nd CPU:
> >> >>> panic()->crash_kexec()->kexec_mutex already held by 1st CPU
> >> >>> ->smp_send_stop()-> stop CPU 1 (stop kdump)
> >> >>>
> >> >>> How should we fix this problem? One possibility could be to do
> >> >>> smp_send_stop() before we call crash_kexec().
>
> http://lkml.org/lkml/2010/9/16/353
>
> I developed a patch solving this issue one year ago.
> (Just adding local_irq_disable in kexec path.)
This won't work (at least on s390) because smp_send_stop() will also
stop CPUs that have interrupts disabled.
Michael
next prev parent reply other threads:[~2011-10-25 8:33 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-24 14:55 Michael Holzheu
2011-10-24 15:14 ` Eric W. Biederman
2011-10-24 15:23 ` Américo Wang
2011-10-24 17:07 ` Eric W. Biederman
2011-10-24 17:33 ` Vivek Goyal
2011-10-24 22:24 ` Seiji Aguchi
2011-10-25 8:33 ` Michael Holzheu [this message]
2011-10-25 8:44 ` Michael Holzheu
2011-10-25 12:04 ` Eric W. Biederman
2011-10-25 14:54 ` Vivek Goyal
2011-10-25 14:58 ` Michael Holzheu
2011-10-25 15:08 ` Vivek Goyal
2011-10-25 15:28 ` Michael Holzheu
2011-10-25 15:28 ` Don Zickus
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