Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH RFC tip/core/rcu 9/9] rcu: Change _wait_rcu_gp() to work around GCC bug 67055 | Date | Fri, 28 Aug 2015 20:36:01 -0700 |
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From: Oleg Nesterov <oleg@redhat.com>
Code like this in inline functions confuses some recent versions of gcc:
const int n = const-expr; whatever_t array[n];
For more details, see:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67055#c13
This compiler bug results in the following failure after 114b7fd4b (rcu: Create rcu_sync infrastructure):
In file included from include/linux/rcupdate.h:429:0, from include/linux/rcu_sync.h:5, from kernel/rcu/sync.c:1: include/linux/rcutiny.h: In function 'rcu_barrier_sched': include/linux/rcutiny.h:55:20: internal compiler error: Segmentation fault static inline void rcu_barrier_sched(void)
This commit therefore eliminates the constant local variable in favor of direct use of the expression.
Reported-and-tested-by: Mark Salter <msalter@redhat.com> Reported-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- include/linux/rcupdate.h | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index ff476515f716..581abf848566 100644 --- 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__) -- 1.8.1.5
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