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

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Date:   Thu, 2 Mar 2017 00:36:50 -0800
From:   tip-bot for Thomas Gleixner <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     tglx@...utronix.de, sergey.senozhatsky.work@...il.com,
        linux-kernel@...r.kernel.org, mingo@...nel.org, bp@...en8.de,
        sergey.senozhatsky@...il.com, hpa@...or.com, peterz@...radead.org,
        rjw@...k.pl
Subject: [tip:x86/urgent] x86/hpet: Prevent might sleep splat on resume

Commit-ID:  bb1a2c26165640ba2cbcfe06c81e9f9d6db4e643
Gitweb:     http://git.kernel.org/tip/bb1a2c26165640ba2cbcfe06c81e9f9d6db4e643
Author:     Thomas Gleixner <tglx@...utronix.de>
AuthorDate: Wed, 1 Mar 2017 21:10:17 +0100
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Thu, 2 Mar 2017 09:33:47 +0100

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-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>

---
 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 dc6ba5b..89ff7af 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -354,7 +354,7 @@ 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);
 	}