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 | ||
| cpu | ||
| timers | ||
| apic.c | ||
| apm.c | ||
| asm-offsets.c | ||
| bootflag.c | ||
| cpuid.c | ||
| crash_dump.c | ||
| crash.c | ||
| dmi_scan.c | ||
| doublefault.c | ||
| early_printk.c | ||
| efi_stub.S | ||
| efi.c | ||
| entry.S | ||
| head.S | ||
| i386_ksyms.c | ||
| i387.c | ||
| i8237.c | ||
| i8259.c | ||
| init_task.c | ||
| io_apic.c | ||
| ioport.c | ||
| irq.c | ||
| kprobes.c | ||
| ldt.c | ||
| machine_kexec.c | ||
| Makefile | ||
| mca.c | ||
| microcode.c | ||
| module.c | ||
| mpparse.c | ||
| msr.c | ||
| nmi.c | ||
| numaq.c | ||
| pci-dma.c | ||
| process.c | ||
| ptrace.c | ||
| quirks.c | ||
| reboot_fixups.c | ||
| reboot.c | ||
| relocate_kernel.S | ||
| scx200.c | ||
| semaphore.c | ||
| setup.c | ||
| sigframe.h | ||
| signal.c | ||
| smp.c | ||
| smpboot.c | ||
| srat.c | ||
| summit.c | ||
| sys_i386.c | ||
| syscall_table.S | ||
| sysenter.c | ||
| time_hpet.c | ||
| time.c | ||
| trampoline.S | ||
| traps.c | ||
| vm86.c | ||
| vmlinux.lds.S | ||
| vsyscall-int80.S | ||
| vsyscall-note.S | ||
| vsyscall-sigreturn.S | ||
| vsyscall-sysenter.S | ||
| vsyscall.lds.S | ||
| vsyscall.S | ||