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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DCA78C433EF for ; Fri, 17 Dec 2021 07:42:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233758AbhLQHmQ (ORCPT ); Fri, 17 Dec 2021 02:42:16 -0500 Received: from mga03.intel.com ([134.134.136.65]:41153 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229449AbhLQHmO (ORCPT ); Fri, 17 Dec 2021 02:42:14 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1639726934; x=1671262934; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=ihr/UeVcwH+/UbgClCubV8h0JbZ+Jwe/QpDzJPDzJ0o=; b=Vru0HX9XfI8cHrACicJ57mf0YTqT5WzpsadTRxrSiVk/wBNlvVZk6cCx lSe2fnH7w9dpoEBqNNxVehesZEHx9y23VTvLLrLpDXKX0WcWeLtBfTKUR BUfEUA9Lm3VbKysKtkajrISU73F8U3TtXwEeh3t6ZXHJAIWlbQlBADrZp Rqp+WUdadDAs680yJQtBlNqKvSb9wQzx9cD95CSJPmAVOFXwMCngR4DzH 9q5b8nY676EG+DOzMayc4S/vD4WpzENSjGSDpW7zARYtkF1PKgNmT1OrR YfNxNkNz1pIL/TnFtszoxKHtLm0apexrEfD6qJwRz7/LxlA8pjo1rYOh/ w==; X-IronPort-AV: E=McAfee;i="6200,9189,10200"; a="239651135" X-IronPort-AV: E=Sophos;i="5.88,213,1635231600"; d="scan'208";a="239651135" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Dec 2021 23:42:13 -0800 X-IronPort-AV: E=Sophos;i="5.88,213,1635231600"; d="scan'208";a="519641766" Received: from unknown (HELO zq-VirtualBox.bj.intel.com) ([10.238.128.201]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Dec 2021 23:42:10 -0800 From: Zqiang To: peterz@infradead.org, mingo@redhat.com, will@kernel.org, longman@redhat.com Cc: linux-kernel@vger.kernel.org, qiang1.zhang@intel.com Subject: [PATCH v2] locking/rtmutex: Fix incorrect spinning condition Date: Fri, 17 Dec 2021 15:42:07 +0800 Message-Id: <20211217074207.77425-1-qiang1.zhang@intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When the lock owner is on CPU and not need resched, the current waiter need to be checked, if it not longer top the waiter, stop spinning. Fixes: c3123c431447 ("locking/rtmutex: Dont dereference waiter lockless") Signed-off-by: Zqiang --- v1->v2: Modify description information. kernel/locking/rtmutex.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c index 0c1f2e3f019a..8555c4efe97c 100644 --- a/kernel/locking/rtmutex.c +++ b/kernel/locking/rtmutex.c @@ -1383,7 +1383,7 @@ static bool rtmutex_spin_on_owner(struct rt_mutex_base *lock, * - the VCPU on which owner runs is preempted */ if (!owner_on_cpu(owner) || need_resched() || - rt_mutex_waiter_is_top_waiter(lock, waiter)) { + !rt_mutex_waiter_is_top_waiter(lock, waiter)) { res = false; break; } -- 2.25.1