Re: workqueue, pci: INFO: possible recursive locking detected

[Lai Jiangshan]

On 07/19/2013 04:57 PM, Srivatsa S. Bhat wrote:
> On 07/19/2013 07:17 AM, Lai Jiangshan wrote:
>> On 07/19/2013 04:23 AM, Srivatsa S. Bhat wrote:
>>>
>>> ---
>>>
>>>  kernel/workqueue.c |    6 ++++++
>>>  1 file changed, 6 insertions(+)
>>>
>>>
>>> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
>>> index f02c4a4..07d9a67 100644
>>> --- a/kernel/workqueue.c
>>> +++ b/kernel/workqueue.c
>>> @@ -4754,7 +4754,13 @@ long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
>>>  {
>>>  	struct work_for_cpu wfc = { .fn = fn, .arg = arg };
>>>  
>>> +#ifdef CONFIG_LOCKDEP
>>> +	static struct lock_class_key __key;
>>
>> Sorry, this "static" should be removed.
>>
> 
> That didn't help either :-( Because it makes lockdep unhappy,
> since the key isn't persistent.
> 
> This is the patch I used:
> 
> ---
> 
> diff --git a/kernel/workqueue.c b/kernel/workqueue.c
> index f02c4a4..7967e3b 100644
> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -4754,7 +4754,13 @@ long work_on_cpu(int cpu, long (*fn)(void *), void *arg)
>  {
>  	struct work_for_cpu wfc = { .fn = fn, .arg = arg };
> 
> +#ifdef CONFIG_LOCKDEP
> +	struct lock_class_key __key;
> +	INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn);
> +	lockdep_init_map(&wfc.work.lockdep_map, "&wfc.work", &__key, 0);
> +#else
>  	INIT_WORK_ONSTACK(&wfc.work, work_for_cpu_fn);
> +#endif
>  	schedule_work_on(cpu, &wfc.work);
>  	flush_work(&wfc.work);
>  	return wfc.ret;
> 
> 
> And here are the new warnings:
> 
> 
> Block layer SCSI generic (bsg) driver version 0.4 loaded (major 252)
> io scheduler noop registered
> io scheduler deadline registered
> io scheduler cfq registered (default)
> BUG: key ffff881039557b98 not in .data!
> ------------[ cut here ]------------
> WARNING: CPU: 8 PID: 1 at kernel/lockdep.c:2987 lockdep_init_map+0x168/0x170()

Sorry again.