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From: Andrew Morton <akpm@osdl.org>
To: Ingo Molnar <mingo@elte.hu>
Cc: rmk+lkml@arm.linux.org.uk, linux-kernel@vger.kernel.org
Subject: Re: [patch] fix emergency reboot: call reboot notifier list if possible
Date: Wed, 17 Jan 2007 02:03:43 -0800	[thread overview]
Message-ID: <20070117020343.8622e44d.akpm@osdl.org> (raw)
In-Reply-To: <20070117093917.GA7538@elte.hu>

> On Wed, 17 Jan 2007 10:39:17 +0100 Ingo Molnar <mingo@elte.hu> wrote:
> 
> * Russell King <rmk+lkml@arm.linux.org.uk> wrote:
> 
> > On Wed, Jan 17, 2007 at 10:13:19AM +0100, Ingo Molnar wrote:
> > > we dont call the reboot notifiers during emergency reboot mainly because 
> > > it could be called from atomic context and reboot notifiers are a 
> > > blocking notifier list. But actually the kernel is often perfectly 
> > > reschedulable in this stage, so we could as well process the 
> > > reboot_notifier_list.
> > 
> > My experience has been that when there has been the need to use this
> > facility, the kernel hasn't been reschedulable. [...]
> 
> this decision is totally automatic - so if your situation happens and 
> the kernel isnt reschedulable, then the notifier chain wont be called 
> and nothing changes from your perspective. Hm, perhaps this should be 
> dependent on CONFIG_PREEMPT, to make sure preempt_count() is reliable?
> 
> but from my perspective this patch fixes a real regression.
> 
> updated patch attached below.
> 

Making it dependent upon CONFIG_PREEMPT seems a bit sucky.  Perhaps pass in
some "you were called from /proc/sysrq-trigger" notification?

Also, there are ways of telling if the kernel has oopsed (oops counter,
oops_in_progress, etc) which should perhaps be tested.

Or just learn to type `reboot -fn' ;)


  reply	other threads:[~2007-01-17 10:03 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-01-17  9:13 Ingo Molnar
2007-01-17  9:22 ` Russell King
2007-01-17  9:39   ` Ingo Molnar
2007-01-17 10:03     ` Andrew Morton [this message]
2007-01-17 10:25       ` Ingo Molnar
2007-01-23 19:57       ` Pavel Machek
2007-01-24 16:30         ` Randy Dunlap
2007-01-24 17:49           ` linux-os (Dick Johnson)
2007-01-17  9:51 ` [patch] KVM: do VMXOFF upon reboot Ingo Molnar
2007-01-17 10:02   ` Ingo Molnar
2007-01-21 10:17     ` Avi Kivity

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