This is a note to let you know that I've just added the patch titled PM / reboot: call syscore_shutdown() after disable_nonboot_cpus() to the 3.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pm-reboot-call-syscore_shutdown-after-disable_nonboot_cpus.patch and it can be found in the queue-3.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 6f389a8f1dd22a24f3d9afc2812b30d639e94625 Mon Sep 17 00:00:00 2001 From: Huacai Chen <chenhc@xxxxxxxxxx> Date: Sun, 7 Apr 2013 02:14:14 +0000 Subject: PM / reboot: call syscore_shutdown() after disable_nonboot_cpus() 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 @@ -323,7 +323,6 @@ void kernel_restart_prepare(char *cmd) system_state = SYSTEM_RESTART; usermodehelper_disable(); device_shutdown(); - syscore_shutdown(); } /** @@ -369,6 +368,7 @@ void kernel_restart(char *cmd) { kernel_restart_prepare(cmd); disable_nonboot_cpus(); + syscore_shutdown(); if (!cmd) printk(KERN_EMERG "Restarting system.\n"); else @@ -394,6 +394,7 @@ static void kernel_shutdown_prepare(enum void kernel_halt(void) { kernel_shutdown_prepare(SYSTEM_HALT); + disable_nonboot_cpus(); syscore_shutdown(); printk(KERN_EMERG "System halted.\n"); kmsg_dump(KMSG_DUMP_HALT); Patches currently in stable-queue which might be from chenhc@xxxxxxxxxx are queue-3.8/pm-reboot-call-syscore_shutdown-after-disable_nonboot_cpus.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html