linux-kernel - [PATCH AUTOSEL for 4.4 03/32] x86/hpet: Prevent might sleep splat on resume

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Message-ID: <20171129172141.28925-3-alexander.levin@verizon.com>
Date:   Wed, 29 Nov 2017 17:21:48 +0000
From:   alexander.levin@...izon.com
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Cc:     Thomas Gleixner <tglx@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        "Rafael J. Wysocki" <rjw@...k.pl>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        Borislav Petkov <bp@...en8.de>, alexander.levin@...izon.com
Subject: [PATCH AUTOSEL for 4.4 03/32] x86/hpet: Prevent might sleep splat on
 resume

From: Thomas Gleixner <tglx@...utronix.de>

[ Upstream commit bb1a2c26165640ba2cbcfe06c81e9f9d6db4e643 ]

Sergey reported a might sleep warning triggered from the hpet resume
path. It's caused by the call to disable_irq() from interrupt disabled
context.

The problem with the low level resume code is that it is not accounted as a
special system_state like we do during the boot process. Calling the same
code during system boot would not trigger the warning. That's inconsistent
at best.

In this particular case it's trivial to replace the disable_irq() with
disable_hardirq() because this particular code path is solely used from
system resume and the involved hpet interrupts can never be force threaded.

Reported-and-tested-by: Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: "Rafael J. Wysocki" <rjw@...k.pl>
Cc: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Cc: Borislav Petkov <bp@...en8.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1703012108460.3684@nanos
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Signed-off-by: Sasha Levin <alexander.levin@...izon.com>
---
 arch/x86/kernel/hpet.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index acc9b8f19ca8..f48eb8eeefe2 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -353,7 +353,7 @@ static int hpet_resume(struct clock_event_device *evt, int timer)
 
 		irq_domain_deactivate_irq(irq_get_irq_data(hdev->irq));
 		irq_domain_activate_irq(irq_get_irq_data(hdev->irq));
-		disable_irq(hdev->irq);
+		disable_hardirq(hdev->irq);
 		irq_set_affinity(hdev->irq, cpumask_of(hdev->cpu));
 		enable_irq(hdev->irq);
 	}
-- 
2.11.0