Re: [PATCH 2.6.14-rc1-git5] sched: disable preempt in idle tasks

[Nick Piggin <nickpiggin@yahoo.com.au>]

Andrew Morton wrote:
> Nick Piggin <nickpiggin@yahoo.com.au> wrote:
>
> > This patch should hopefully fix Nigel's bug.
> >
> > Split out from sched-resched-opt.patch. Tested on i386 with acpi idle
> > and poll idle (previous iterations tested on various other architectures).
>
>
> This makes the emt64 machine reboot itself, which iirc was the behaviour in
> the failing patch from which this one was split out.
>
> The machine is using acpi_processor_idle().

OK, thanks. That must be the preempt_disable() being called in
start_secondary(). Maybe I should have listened to the comment.

Can you try the following patch?

--
SUSE Labs, Novell Inc.

Index: linux-2.6/arch/x86_64/kernel/smpboot.c
===================================================================
--- linux-2.6.orig/arch/x86_64/kernel/smpboot.c	2005-09-22 01:04:03.000000000 +1000
+++ linux-2.6/arch/x86_64/kernel/smpboot.c	2005-09-22 13:24:11.000000000 +1000
@@ -473,8 +473,8 @@ void __cpuinit start_secondary(void)
 	 * booting is too fragile that we want to limit the
 	 * things done here to the most necessary things.
 	 */
-	preempt_disable();
 	cpu_init();
+	preempt_disable();
 	smp_callin();
 
 	/* otherwise gcc will move up the smp_processor_id before the cpu_init */