Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755828AbbHYSru (ORCPT ); Tue, 25 Aug 2015 14:47:50 -0400 Received: from mx1.redhat.com ([209.132.183.28]:58006 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753974AbbHYSrt (ORCPT ); Tue, 25 Aug 2015 14:47:49 -0400 Date: Tue, 25 Aug 2015 20:45:18 +0200 From: Oleg Nesterov To: "Paul E. McKenney" Cc: Mark Salter , Yoshinori Sato , uclinux-h8-devel@lists.sourceforge.jp, "linux-kernel@vger.kernel.org" , "Peter Zijlstra (Intel)" , Josh Triplett , Guenter Roeck Subject: [PATCH] rcu: change _wait_rcu_gp() to work around gcc 67055 bug Message-ID: <20150825184518.GA15234@redhat.com> References: <55DB63AC.7070305@roeck-us.net> <8737z7nc7b.wl-ysato@users.sourceforge.jp> <1440512875.5882.16.camel@redhat.com> <55DC83C7.1060809@roeck-us.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <55DC83C7.1060809@roeck-us.net> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1982 Lines: 60 The code like const int n = const-expr; whatever_t array[n]; in inline function can confuse gcc, see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67055#c13 This leads to In file included from include/linux/rcupdate.h:429:0, from include/linux/rcusync.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) build failure after ec90a194a "rcu: Create a synchronize_rcu_mult()" and 114b7fd4b "rcu: Create rcu_sync infrastructure" meet each other. Reported-and-tested-by: Mark Salter Reported-by: Guenter Roeck Signed-off-by: Oleg Nesterov --- 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 ff47651..c353c2b 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__) -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/