From: Matthew Garrett <mjg@redhat.com>
To: "Luck, Tony" <tony.luck@intel.com>
Cc: Don Zickus <dzickus@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: pstore dump inside an nmi handler
Date: Fri, 8 Jul 2011 22:49:41 +0100 [thread overview]
Message-ID: <20110708214941.GA20511@srcf.ucam.org> (raw)
In-Reply-To: <987664A83D2D224EAE907B061CE93D5301E981AB56@orsmsx505.amr.corp.intel.com>
On Fri, Jul 08, 2011 at 02:40:13PM -0700, Luck, Tony wrote:
> > Inside pstore_dump(), the first thing it tries to grab is a mutex_lock()
> > (inside an nmi hander). This seems to be the root cause of my problems.
>
> Someone else pointed out that mutex_lock() is a problem here too. They
> wondered whether spin_lock_irqsave() would work - or whether pstore
> backends were allowed to sleep - to which I said I hoped they didn't,
> but wasn't really sure what the future will hold.
EFI can't sleep (at least, not as far as the kernel's concerned), so
we're safe there. I think it's fair to assume atomicity here - crash
dumping is a pretty specific situation. Although we may need to think
about whether pstore should be saving reboot and poweroff in that case.
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2011-07-08 21:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-08 20:17 pstore dump inside an nmi handler Don Zickus
2011-07-08 21:40 ` Luck, Tony
2011-07-08 21:48 ` David Miller
2011-07-08 21:49 ` Matthew Garrett [this message]
2011-07-08 22:10 ` Luck, Tony
2011-07-11 15:39 ` Don Zickus
2011-07-13 18:15 ` Luck, Tony
2011-07-14 13:49 ` Don Zickus
2011-07-11 21:55 ` Don Zickus
2011-07-12 15:34 ` Don Zickus
2011-07-13 16:58 ` Luck, Tony
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