lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  PHC 
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 28 Jul 2014 12:24:27 -0700
From:	John Stultz <>
To:	Stephen Boyd <>,
	Soren Brinkmann <>
CC:	Thomas Gleixner <>,
	"Rafael J. Wysocki" <>,
	Pavel Machek <>, Len Brown <>,,,
	Daniel Lezcano <>
Subject: Re: [PATCH RFC v2] PM / sleep: Fix racing timers

On 07/28/2014 12:19 PM, Stephen Boyd wrote:
> On 07/25/14 14:06, Soren Brinkmann wrote:
>> On platforms that do not power off during suspend, successfully entering
>> suspend races with timers.
>> The race happening in a couple of location is:
>>   1. disable IRQs   		(e.g. arch_suspend_disable_irqs())
>>      ...
>>   2. syscore_suspend()
>>       -> timekeeping_suspend()
>>        -> clockevents_notify(SUSPEND)
>>         -> tick_suspend()   	(timers are turned off here)
>>      ...
>>   3. wfi            		(wait for wake-IRQ here)
>> Between steps 1 and 2 the timers can still generate interrupts that are
>> not handled and stay pending until step 3. That pending IRQ causes an
>> immediate - spurious - wake.
>> The solution is to move the clockevents suspend/resume notification
>> out of the syscore_suspend step and explictly call them at the appropriate
>> time in the suspend/hibernation paths. I.e. timers are suspend _before_
>> IRQs get disabled. And accordingly in the resume path.
>> Signed-off-by: Soren Brinkmann <>
> Do we know which timer_list or hrtimer wants to run while entering
> suspend? I'd suspect the scheduler tick but perhaps we just forgot to
> cancel some timer during suspend?

Though, canceling timers really shouldn't be necessary for
suspend/resume, no?


To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

Powered by blists - more mailing lists