Subject: [PATCH v2 2/3] powerpc: hard disable irqs in smp_send_stop loop

From: Nicholas Piggin <[email-masked]>
Date: Sun, 1 Apr 2018 20:36:14 +1000

The hard lockup watchdog can fire under local_irq_disable
on platforms with irq soft masking.

Signed-off-by: Nicholas Piggin <[email-masked]>
---
 arch/powerpc/kernel/smp.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index db88660bf6bd..e16ec7b3b427 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -574,9 +574,10 @@ static void stop_this_cpu(void *dummy)
 	/* Remove this CPU */
 	set_cpu_online(smp_processor_id(), false);
 
-	local_irq_disable();
+	hard_irq_disable();
+	spin_begin();
 	while (1)
-		;
+		spin_cpu_relax();
 }
 
 void smp_send_stop(void)
-- 
2.16.3