From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Rothwell Subject: linux-next: build failure after merge of the rcu tree Date: Fri, 11 Aug 2017 14:43:52 +1000 Message-ID: <20170811144352.585085e2@canb.auug.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from ozlabs.org ([103.22.144.67]:50525 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750815AbdHKEny (ORCPT ); Fri, 11 Aug 2017 00:43:54 -0400 Sender: linux-next-owner@vger.kernel.org List-ID: To: "Paul E. McKenney" , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Peter Zijlstra Cc: Linux-Next Mailing List , Linux Kernel Mailing List Hi Paul, After merging the rcu tree, today's linux-next build (arm multi_v7_defconfig) failed like this: kernel/sched/core.c: In function 'do_task_dead': kernel/sched/core.c:3385:2: error: implicit declaration of function 'smp_mb__before_spinlock' [-Werror=implicit-function-declaration] smp_mb__before_spinlock(); ^ cc1: some warnings being treated as errors Caused by commit 4a6fc6107e90 ("sched: Replace spin_unlock_wait() with lock/unlock pair") Interacting with commit a9668cd6ee28 ("locking: Remove smp_mb__before_spinlock()") from the tip tree. I applied this patch for now, but I assume something better is required. From: Stephen Rothwell Date: Fri, 11 Aug 2017 14:32:10 +1000 Subject: [PATCH] sched: temporary hack for locking: Remove smp_mb__before_spinlock() Signed-off-by: Stephen Rothwell --- kernel/sched/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 2bd00feaea15..a4f4ba2e3be6 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3382,7 +3382,7 @@ void __noreturn do_task_dead(void) * To avoid it, we have to wait for releasing tsk->pi_lock which * is held by try_to_wake_up() */ - smp_mb__before_spinlock(); + smp_mb(); raw_spin_lock_irq(¤t->pi_lock); raw_spin_unlock_irq(¤t->pi_lock); -- Cheers, Stephen Rothwell