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6e3fbee5f1
So why are we calling smp_send_stop from machine_halt? We don't. Looking more closely at the bug report the problem here is that halt -p is called which triggers not a halt but an attempt to power off. machine_power_off calls machine_shutdown which calls smp_send_stop. If pm_power_off is set we should never make it out machine_power_off to the call of do_exit. So pm_power_off must not be set in this case. When pm_power_off is not set we expect machine_power_off to devolve into machine_halt. So how do we fix this? Playing too much with smp_send_stop is dangerous because it must also be safe to be called from panic. It looks like the obviously correct fix is to only call machine_shutdown when pm_power_off is defined. Doing that will make Andi's assumption about not scheduling true and generally simplify what must be supported. This turns machine_power_off into a noop like machine_halt when pm_power_off is not defined. If the expected behavior is that sys_reboot(LINUX_REBOOT_CMD_POWER_OFF) becomes sys_reboot(LINUX_REBOOT_CMD_HALT) if pm_power_off is NULL this is not quite a comprehensive fix as we pass a different parameter to the reboot notifier and we set system_state to a different value before calling device_shutdown(). Unfortunately any fix more comprehensive I can think of is not obviously correct. The core problem is that there is no architecture independent way to detect if machine_power will become a noop, without calling it. Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org> |
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.. | ||
acpi | ||
cpufreq | ||
aperture.c | ||
apic.c | ||
asm-offsets.c | ||
crash.c | ||
crash_dump.c | ||
e820.c | ||
early_printk.c | ||
entry.S | ||
genapic.c | ||
genapic_cluster.c | ||
genapic_flat.c | ||
head.S | ||
head64.c | ||
i387.c | ||
i8259.c | ||
init_task.c | ||
io_apic.c | ||
ioport.c | ||
irq.c | ||
kprobes.c | ||
ldt.c | ||
machine_kexec.c | ||
Makefile | ||
mce.c | ||
mce_amd.c | ||
mce_intel.c | ||
module.c | ||
mpparse.c | ||
nmi.c | ||
pci-dma.c | ||
pci-gart.c | ||
pci-nommu.c | ||
pmtimer.c | ||
process.c | ||
ptrace.c | ||
reboot.c | ||
relocate_kernel.S | ||
setup.c | ||
setup64.c | ||
signal.c | ||
smp.c | ||
smpboot.c | ||
suspend.c | ||
suspend_asm.S | ||
sys_x86_64.c | ||
syscall.c | ||
time.c | ||
trampoline.S | ||
traps.c | ||
vmlinux.lds.S | ||
vsyscall.c | ||
x8664_ksyms.c |