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Date: Thu, 17 Aug 2017 09:48:11 +0200
From: Ingo Molnar <mingo@kernel.org>
To: Boqun Feng <boqun.feng@gmail.com>
Cc: Byungchul Park <byungchul.park@lge.com>,
        Thomas Gleixner <tglx@linutronix.de>, peterz@infradead.org,
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        linux-mm@kvack.org, akpm@linux-foundation.org, willy@infradead.org,
        npiggin@gmail.com, kernel-team@lge.com
Subject: Re: [PATCH v8 00/14] lockdep: Implement crossrelease feature
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* Boqun Feng <boqun.feng@gmail.com> wrote:

> --- a/kernel/workqueue.c
> +++ b/kernel/workqueue.c
> @@ -2431,6 +2431,27 @@ struct wq_barrier {
>  	struct task_struct	*task;	/* purely informational */
>  };
>  
> +#ifdef CONFIG_LOCKDEP_COMPLETE
> +# define INIT_WQ_BARRIER_ONSTACK(barr, func, target)				\
> +do {										\
> +	INIT_WORK_ONSTACK(&(barr)->work, func);					\
> +	__set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&(barr)->work));	\
> +	lockdep_init_map_crosslock((struct lockdep_map *)&(barr)->done.map,	\
> +				   "(complete)" #barr,				\
> +				   (target)->lockdep_map.key, 1); 		\
> +	__init_completion(&barr->done);						\
> +	barr->task = current;							\
> +} while (0)
> +#else
> +# define INIT_WQ_BARRIER_ONSTACK(barr, func, target)				\
> +do {										\
> +	INIT_WORK_ONSTACK(&(barr)->work, func);					\
> +	__set_bit(WORK_STRUCT_PENDING_BIT, work_data_bits(&(barr)->work));	\
> +	init_completion(&barr->done);						\
> +	barr->task = current;							\
> +} while (0)
> +#endif

Is there any progress with this bug? This false positive warning regression is 
blocking the locking tree.

BTW., I don't think the #ifdef is necessary: lockdep_init_map_crosslock should map 
to nothing when lockdep is disabled, right?

Thanks,

	Ingo