[PATCH] (repost) Fix SMP poweroff hangs

From: Mark Lord
Date: Fri Sep 28 2007 - 15:53:31 EST

Rafael J. Wysocki wrote:
@@ -879,6 +880,7 @@
if (pm_power_off_prepare)
+ disable_nonboot_cpus();

Before sysdev_shutdown(), please.

sysdev_shutdown() may touch things that belong to CPU0.

Thanks. Here is the revised patch.

* * *

We need to disable all CPUs other than the boot CPU (usually 0)
before attempting to power-off modern SMP machines.
This fixes the hang-on-poweroff issue on my MythTV SMP box,
and also on Thomas Gleixner's new toybox.

Signed-off-by: Mark Lord <mlord@xxxxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

--- linux/kernel/sys.c.orig 2007-09-13 09:49:11.000000000 -0400
+++ linux/kernel/sys.c 2007-09-28 15:48:54.000000000 -0400
@@ -32,6 +32,7 @@
#include <linux/getcpu.h>
#include <linux/task_io_accounting_ops.h>
#include <linux/seccomp.h>
+#include <linux/cpu.h>

#include <linux/compat.h>
#include <linux/syscalls.h>
@@ -878,6 +879,7 @@
if (pm_power_off_prepare)
+ disable_nonboot_cpus();
printk(KERN_EMERG "Power down.\n");
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