linux-kernel - Re: [2.6.29-rc2] Inconsistent lock state on resume in hres_timers

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Message-Id: <1232307860.5204.23.camel@laptop>
Date:	Sun, 18 Jan 2009 20:44:20 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Andrey Borzenkov <arvidjaar@...l.ru>
Cc:	Ingo Molnar <mingo@...e.hu>, linux-kernel@...r.kernel.org,
	Thomas Gleixner <tglx@...utronix.de>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: Re: [2.6.29-rc2] Inconsistent lock state on resume in
 hres_timers_resume

On Sun, 2009-01-18 at 22:32 +0300, Andrey Borzenkov wrote:
> On 18 января 2009 20:25:11 Ingo Molnar wrote:
> 
> > Rafael, can you think of anything in the s2ram code that would have
> >
> > changed the irqs-off status of hres_timers_resume() in this codepath:
> > > > [17854.688347]  [<c013711a>] hres_timers_resume+0xa/0x10
> > > > [17854.688347]  [<c013aa8e>] timekeeping_resume+0xee/0x150
> > > > [17854.688347]  [<c0273384>] __sysdev_resume+0x14/0x50
> > > > [17854.688347]  [<c0273407>] sysdev_resume+0x47/0x80
> > > > [17854.688347]  [<c02791ab>] device_power_up+0xb/0x20
> > > > [17854.688347]  [<c015043f>] suspend_devices_and_enter+0xcf/0x150
> > > > [17854.688347]  [<c0150c2f>] ? freeze_processes+0x3f/0x90
> > > > [17854.688347]  [<c0150614>] enter_state+0xf4/0x140
> > > > [17854.688347]  [<c01506dd>] state_store+0x7d/0xc0
> >
> > ?
> >
> 
> As far as I can tell, timekeeping_resume is called via class ->resume 
> method; and according to comments in sysdev_resume() and 
> device_power_up(), they are called with interrupts disabled.
> 
> Looking at suspend_enter, irqs *are* disabled at this point.
> 
> So it actually looks like something (may be some driver) unconditionally 
> enabled irqs in resume path.
> 
> I believe the patch should be hold back until this is clarified.

Something like so then?

diff --git a/drivers/base/sys.c b/drivers/base/sys.c
index c98c31e..53868b8 100644
--- a/drivers/base/sys.c
+++ b/drivers/base/sys.c
@@ -341,13 +341,17 @@ static void __sysdev_resume(struct sys_device *dev)
 	struct sysdev_driver *drv;
 
 	/* First, call the class-specific one */
-	if (cls->resume)
+	if (cls->resume) {
 		cls->resume(dev);
+		WARN(!irqs_disabled(), "%Fp enabled IRQs\n", cls->resume);
+	}
 
 	/* Call auxillary drivers next. */
 	list_for_each_entry(drv, &cls->drivers, entry) {
-		if (drv->resume)
+		if (drv->resume) {
 			drv->resume(dev);
+			WARN(!irqs_disabled(), "%Fp enabled IRQs\n", drv->resume);
+		}
 	}
 }
 


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