Mark Lord wrote:
We need to disable all CPUs other than the boot CPU (usually 0) before attempting to power-off modern SMP machines. This seems to fix the hang-on-poweroff issue that one of my SMP boxes exhibits. More testing required. Signed-off-by: Mark Lord <[EMAIL PROTECTED]> --- --- linux/kernel/sys.c.orig 2007-09-13 09:49:11.000000000 -0400 +++ linux/kernel/sys.c 2007-09-28 09:48:54.000000000 -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> @@ -879,6 +880,7 @@ if (pm_power_off_prepare) pm_power_off_prepare(); sysdev_shutdown(); + disable_nonboot_cpus(); printk(KERN_EMERG "Power down.\n"); machine_power_off(); }
Okay, verified now. Prior to this patch, *both* CPUs were still up and running when machine_power_off() got called, and there was no guarantee that CPU0 was the one calling machine_power_off(). BUG. The above patch guarantees that only the single boot CPU is running and calling machine_power_off(). Hopefully this buries the SMP-power-off bogeyman for good! Cheers - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/