[ 04/17] PM / reboot: call syscore_shutdown() after disable_nonboot_cpus()

From: Greg Kroah-Hartman
Date: Sun Apr 14 2013 - 22:28:58 EST

3.4-stable review patch. If anyone has any objections, please let me know.


From: Huacai Chen <chenhc@xxxxxxxxxx>

commit 6f389a8f1dd22a24f3d9afc2812b30d639e94625 upstream.

As commit 40dc166c (PM / Core: Introduce struct syscore_ops for core
subsystems PM) say, syscore_ops operations should be carried with one
CPU on-line and interrupts disabled. However, after commit f96972f2d
(kernel/sys.c: call disable_nonboot_cpus() in kernel_restart()),
syscore_shutdown() is called before disable_nonboot_cpus(), so break
the rules. We have a MIPS machine with a 8259A PIC, and there is an
external timer (HPET) linked at 8259A. Since 8259A has been shutdown
too early (by syscore_shutdown()), disable_nonboot_cpus() runs without
timer interrupt, so it hangs and reboot fails. This patch call
syscore_shutdown() a little later (after disable_nonboot_cpus()) to
avoid reboot failure, this is the same way as poweroff does.

For consistency, add disable_nonboot_cpus() to kernel_halt().

Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

kernel/sys.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -320,7 +320,6 @@ void kernel_restart_prepare(char *cmd)
system_state = SYSTEM_RESTART;
- syscore_shutdown();

@@ -366,6 +365,7 @@ void kernel_restart(char *cmd)
+ syscore_shutdown();
if (!cmd)
printk(KERN_EMERG "Restarting system.\n");
@@ -391,6 +391,7 @@ static void kernel_shutdown_prepare(enum
void kernel_halt(void)
+ disable_nonboot_cpus();
printk(KERN_EMERG "System halted.\n");

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/