From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5AE5C169C4 for ; Wed, 6 Feb 2019 18:56:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9DB4A2083B for ; Wed, 6 Feb 2019 18:56:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727366AbfBFS4c (ORCPT ); Wed, 6 Feb 2019 13:56:32 -0500 Received: from smtp.nue.novell.com ([195.135.221.5]:44713 "EHLO smtp.nue.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726786AbfBFS4b (ORCPT ); Wed, 6 Feb 2019 13:56:31 -0500 Received: from emea4-mta.ukb.novell.com ([10.120.13.87]) by smtp.nue.novell.com with ESMTP (TLS encrypted); Wed, 06 Feb 2019 19:56:29 +0100 Received: from linux-r8p5.suse.de (nwb-a10-snat.microfocus.com [10.120.13.202]) by emea4-mta.ukb.novell.com with ESMTP (TLS encrypted); Wed, 06 Feb 2019 18:56:22 +0000 From: Davidlohr Bueso To: mingo@kernel.org, tglx@linutronix.de Cc: peterz@infradead.org, linux-kernel@vger.kernel.org, dave@stgolabs.net, Davidlohr Bueso Subject: [PATCH] kernel/futex: Fix barrier comment Date: Wed, 6 Feb 2019 10:56:02 -0800 Message-Id: <20190206185602.949-1-dave@stgolabs.net> X-Mailer: git-send-email 2.16.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The current comment for the barrier that guarantees that waiter increment is always before taking the hb spinlock (barrier (A)) needs to be fixed. We are obviously referring to hb_waiters_inc, which is a full barrier. Reported-by: Peter Zijlstra Signed-off-by: Davidlohr Bueso --- kernel/futex.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/futex.c b/kernel/futex.c index fdd312da0992..5ec2473a3497 100644 --- a/kernel/futex.c +++ b/kernel/futex.c @@ -2221,11 +2221,11 @@ static inline struct futex_hash_bucket *queue_lock(struct futex_q *q) * decrement the counter at queue_unlock() when some error has * occurred and we don't end up adding the task to the list. */ - hb_waiters_inc(hb); + hb_waiters_inc(hb); /* implies smp_mb(); (A) */ q->lock_ptr = &hb->lock; - spin_lock(&hb->lock); /* implies smp_mb(); (A) */ + spin_lock(&hb->lock); return hb; } -- 2.16.4