From: Nicholas Piggin <npiggin@gmail.com>
Date: Sun, 1 Apr 2018 10:36:14 +0000 (+1000)
Subject: powerpc: hard disable irqs in smp_send_stop loop
X-Git-Tag: v4.17-rc1~86^2~17
X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=855bfe0de1a05a01f89975ea8ba9f5521fb0f567;p=linux-block.git

powerpc: hard disable irqs in smp_send_stop loop

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

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---

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)