diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kernel/smpboot.c | 26 |
1 files changed, 20 insertions, 6 deletions
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c index 27aa04a95702..f5ef689dd62a 100644 --- a/arch/x86/kernel/smpboot.c +++ b/arch/x86/kernel/smpboot.c @@ -1594,14 +1594,28 @@ int native_cpu_disable(void) if (ret) return ret; - /* - * Disable the local APIC. Otherwise IPI broadcasts will reach - * it. It still responds normally to INIT, NMI, SMI, and SIPI - * messages. - */ - apic_soft_disable(); cpu_disable_common(); + /* + * Disable the local APIC. Otherwise IPI broadcasts will reach + * it. It still responds normally to INIT, NMI, SMI, and SIPI + * messages. + * + * Disabling the APIC must happen after cpu_disable_common() + * which invokes fixup_irqs(). + * + * Disabling the APIC preserves already set bits in IRR, but + * an interrupt arriving after disabling the local APIC does not + * set the corresponding IRR bit. + * + * fixup_irqs() scans IRR for set bits so it can raise a not + * yet handled interrupt on the new destination CPU via an IPI + * but obviously it can't do so for IRR bits which are not set. + * IOW, interrupts arriving after disabling the local APIC will + * be lost. + */ + apic_soft_disable(); + return 0; } |