linux-kernel - Re: [LOCKDEP] cpufreq: possible circular locking dependency detected

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Message-ID: <51E50570.8080704@linux.vnet.ibm.com>
Date:	Tue, 16 Jul 2013 14:03:52 +0530
From:	"Srivatsa S. Bhat" <srivatsa.bhat@...ux.vnet.ibm.com>
To:	Sergey Senozhatsky <sergey.senozhatsky@...il.com>
CC:	Michael Wang <wangyun@...ux.vnet.ibm.com>,
	Jiri Kosina <jkosina@...e.cz>, Borislav Petkov <bp@...en8.de>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Viresh Kumar <viresh.kumar@...aro.org>,
	linux-kernel@...r.kernel.org, cpufreq@...r.kernel.org,
	linux-pm@...r.kernel.org,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
Subject: Re: [LOCKDEP] cpufreq: possible circular locking dependency detected

On 07/16/2013 04:50 AM, Sergey Senozhatsky wrote:
> On (07/15/13 18:49), Srivatsa S. Bhat wrote:
> [..]
>> So here is the solution:
>>
>> On 3.11-rc1, apply these patches in the order mentioned below, and check
>> whether it fixes _all_ problems (both the warnings about IPI as well as the
>> lockdep splat).
>>
>> 1. Patch given in:  https://lkml.org/lkml/2013/7/11/661
>>    (Just apply patch 1, not the entire patchset).
>>
>> 2. Apply the patch shown below, on top of the above patch:
>>
>> ---------------------------------------------------------------------------
>>
> 
> Hello Srivatsa,
> Thanks, I'll test a bit later -- in the morning. (laptop stopped resuming from
> suspend, probably radeon dmp).
> 
> 

Sure, thanks!

> 
> Shouldn't we also kick the console lock?
> 
> 
>  kernel/printk.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/kernel/printk.c b/kernel/printk.c
> index d37d45c..3e20233 100644
> --- a/kernel/printk.c
> +++ b/kernel/printk.c
> @@ -1926,8 +1926,11 @@ static int __cpuinit console_cpu_notify(struct notifier_block *self,
>  {
>  	switch (action) {
>  	case CPU_ONLINE:
> +	case CPU_ONLINE_FROZEN:
>  	case CPU_DEAD:
> +	case CPU_DEAD_FROZEN:
>  	case CPU_DOWN_FAILED:
> +	case CPU_DOWN_FAILED_FROZEN:
>  	case CPU_UP_CANCELED:
>  		console_lock();
>  		console_unlock();
> 
> 

No need. suspend_console() and resume_console() already handle it
properly in the suspend/resume case, from what I can see.

Regards,
Srivatsa S. Bhat

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