From: Keir Fraser Date: Sat, 5 Mar 2011 11:34:41 +0000 (+0000) Subject: x86: On CPU offline, fix master waiting for slave to be fully dead. X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=87fe7478aa597f8b9b744d19e3b79a64f3d9cf15;p=xen.git x86: On CPU offline, fix master waiting for slave to be fully dead. On two back-to-back CPU offline operations, on second offline the cpu_state var will be CPU_STATE_DEAD from the first offline. Hence __cpu_die() will incorrectly not wait for the second slave to fully die and set cpu_state itself. The fix is to set cpu_state to a new value, CPU_STATE_DYING, earlier during CPU offline, before __cpu_die() starts to execute. Original diagnosis and patch by Liu, Jinsong Signed-off-by: Keir Fraser --- diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c index 2c8c47d164..7c14f06286 100644 --- a/xen/arch/x86/smpboot.c +++ b/xen/arch/x86/smpboot.c @@ -74,7 +74,8 @@ static void map_cpu_to_logical_apicid(void); static int cpu_error; static enum cpu_state { - CPU_STATE_DEAD = 0, /* slave -> master: I am completely dead */ + CPU_STATE_DYING, /* slave -> master: I am dying */ + CPU_STATE_DEAD, /* slave -> master: I am completely dead */ CPU_STATE_INIT, /* master -> slave: Early bringup phase 1 */ CPU_STATE_CALLOUT, /* master -> slave: Early bringup phase 2 */ CPU_STATE_CALLIN, /* slave -> master: Completed phase 2 */ @@ -834,6 +835,8 @@ void __cpu_disable(void) extern void fixup_irqs(void); int cpu = smp_processor_id(); + set_cpu_state(CPU_STATE_DYING); + local_irq_disable(); clear_local_APIC(); /* Allow any queued timer interrupts to get serviced */ @@ -861,6 +864,7 @@ void __cpu_die(unsigned int cpu) while ( cpu_state != CPU_STATE_DEAD ) { + BUG_ON(cpu_state != CPU_STATE_DYING); mdelay(100); cpu_relax(); process_pending_softirqs();