Patch to avoid calling kernel_power_off when pm_power_off is null. When pm_power_off is null, the platform will not power off in kernel_power_off. Currently, hibernate will call kernel_power_off and then move on to kernel_halt. However, this calls the notifier chain twice with a different parameter. In kernel/reboot.c, this is avoided by checking if pm_power_off is NULL and bypassing kernel_power_off.
Mostly, this is a check if anyone is dependent on having the reboot notifier called 2x if pm_power_off is null. There are some panics if it's called this way in some drivers.
Tested this on omap beaglebone black, but have not tried on other hardware. Please let me know if you can test this on another platform and the results.
Thanks,
Sebastian