Re: h8300 build failures in linux-next (in rcu code, gcc 5.x related, not limited to h8300)

From: Oleg Nesterov
Date: Tue Aug 25 2015 - 14:05:27 EST


On 08/25, Oleg Nesterov wrote:
>
> On 08/26, Yoshinori Sato wrote:
> >
> > Yes.
> > gcc bug #67055.
> > Already fixed in trunk.
>
> Yes, thanks a lot.
>
> Paul, it seems that gcc actually dislikes your ec90a194a "rcu:
> Create a synchronize_rcu_mult()" commit ;) rcu/sync.c was just
> lucky enough to trigger the problem.
>
> I'll try to make the fix today...

Mark, Guenter, any chance you can check if the patch below helps?
It does on x86.

Oleg.

--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -230,12 +230,11 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
struct rcu_synchronize *rs_array);

#define _wait_rcu_gp(checktiny, ...) \
-do { \
- call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
- const int __n = ARRAY_SIZE(__crcu_array); \
- struct rcu_synchronize __rs_array[__n]; \
- \
- __wait_rcu_gp(checktiny, __n, __crcu_array, __rs_array); \
+do { \
+ call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
+ struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)]; \
+ __wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array), \
+ __crcu_array, __rs_array); \
} while (0)

#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)

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