linux-kernel - [PATCH] x86/hpet: Prevent might sleep splat on resume

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Message-ID: <alpine.DEB.2.20.1703012108460.3684@nanos>
Date:   Wed, 1 Mar 2017 21:10:17 +0100 (CET)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
cc:     Borislav Petkov <bp@...en8.de>,
        Peter Zijlstra <peterz@...radead.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
        "Rafael J. Wysocki" <rjw@...k.pl>
Subject: [PATCH] x86/hpet: Prevent might sleep splat on resume

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-by: Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
Cc: stable@...r.kernel.org

---
 arch/x86/kernel/hpet.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -354,7 +354,7 @@ static int hpet_resume(struct clock_even

 		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);
 	}