[RFC PATCH 06/46] x86/smp: Skip offline CPUs for REBOOT_VECTOR in native_stop_other_cpus()

[Pasha Tatashin]

In native_stop_other_cpus(), cpus_stop_mask is initialized to
cpu_online_mask minus the calling CPU. However,
apic_send_IPI_allbutself(REBOOT_VECTOR) uses the APIC broadcast
shorthand when enabled, which delivers the IPI to all physical APICs
including offline CPUs.

Use __apic_send_IPI_mask(&cpus_stop_mask, REBOOT_VECTOR) so that
REBOOT_VECTOR is sent only to the target online CPUs in
cpus_stop_mask.

Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
---
 arch/x86/kernel/smp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index 985103cab16c..2449d15c6667 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -192,7 +192,7 @@ static void native_stop_other_cpus(int wait)
 	cpumask_clear_cpu(this_cpu, &cpus_stop_mask);
 
 	if (!cpumask_empty(&cpus_stop_mask)) {
-		apic_send_IPI_allbutself(REBOOT_VECTOR);
+		__apic_send_IPI_mask(&cpus_stop_mask, REBOOT_VECTOR);
 
 		/*
 		 * Don't wait longer than a second for IPI completion. The
-- 
2.55.0.1082.g2b9226bbc0-goog