Re: [tip: sched/urgent] sched: Fix RANDSTRUCT build fail

[Peter Zijlstra <peterz@infradead.org>]

On Mon, Jun 22, 2020 at 10:10:27AM +0200, Peter Zijlstra wrote:

> Instead of relying on BUG_ON() to ensure the various data structures
> line up, use a bunch of horrible unions.

>  struct irq_work {
> +	union {
> +		struct __call_single_node node;
> +		struct {
> +			struct llist_node llnode;
> +			atomic_t flags;
> +		};
> +	};
>  	void (*func)(struct irq_work *);
>  };

>  struct __call_single_data {
> +	union {
> +		struct __call_single_node node;
> +		struct {
> +			struct llist_node llist;
> +			unsigned int flags;
> +		};
> +	};
>  	smp_call_func_t func;
>  	void *info;
>  };

FWIW, I have 2 further patches, one for each of these structures to get
rid of the horrible union. They are somewhat larger and I was planning
to hold on to them for next round, but if you want them now, I can
certainly do that.