linux-kernel - [PATCH] powerpc/64s: watchdog false positive warning at CPU unplug

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Message-Id: <20170630080740.20766-1-npiggin@gmail.com>
Date:   Fri, 30 Jun 2017 18:07:40 +1000
From:   Nicholas Piggin <npiggin@...il.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     Nicholas Piggin <npiggin@...il.com>,
        Don Zickus <dzickus@...hat.com>, santosiv@...ibm.com,
        linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH] powerpc/64s: watchdog false positive warning at CPU unplug

CPU unplug will call stop_wd_on_cpu regardless if the watchdog has
been configured to be enabled on that CPU. Don't warn in the case
it's not in our enabled mask, this is a valid case.

Fixes: powerpc-64s-implement-arch-specific-hardlockup-watchdog.patch
Reported-by: Santosh Sivaraj <santosiv@...ibm.com>
Signed-off-by: Nicholas Piggin <npiggin@...il.com>
---
 arch/powerpc/kernel/watchdog.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c
index d46040c0da40..93395a53336b 100644
--- a/arch/powerpc/kernel/watchdog.c
+++ b/arch/powerpc/kernel/watchdog.c
@@ -310,10 +310,8 @@ static int start_wd_on_cpu(unsigned int cpu)
 
 static int stop_wd_on_cpu(unsigned int cpu)
 {
-	if (!cpumask_test_cpu(cpu, &wd_cpus_enabled)) {
-		WARN_ON(1);
-		return 0;
-	}
+	if (!cpumask_test_cpu(cpu, &wd_cpus_enabled))
+		return 0; /* Can happen in CPU unplug case */
 
 	stop_watchdog_timer_on(cpu);
 
-- 
2.11.0