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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A80BC433F5 for ; Thu, 14 Oct 2021 02:42:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 59770611C2 for ; Thu, 14 Oct 2021 02:42:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230014AbhJNCoX (ORCPT ); Wed, 13 Oct 2021 22:44:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230010AbhJNCoV (ORCPT ); Wed, 13 Oct 2021 22:44:21 -0400 Received: from mail-pl1-x62b.google.com (mail-pl1-x62b.google.com [IPv6:2607:f8b0:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 01968C061746 for ; Wed, 13 Oct 2021 19:42:17 -0700 (PDT) Received: by mail-pl1-x62b.google.com with SMTP id f21so3143945plb.3 for ; Wed, 13 Oct 2021 19:42:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=IPEZG1UTOCdMILrBYHfNzu5EIxiMBByUqdY5jycPoxc=; b=lxzz23UgvQBpk6EVby72CERgNBPtwtcWXvKbYgUu9rqY5RRWf2XGRJBkfLNEOq+Hnw CnwMGXIh38ez/Uzs4zVLwymHfqIMRxwZ4dVcvCjovXnjgWH9CHGNRi9xMPB5zim4/PaK cwG1ayqWpQMDNtpteDZifV8y1MZmXOFU0phUK00goB0aeV0MHVOGEnoFJ8iWLlT2kWeb fKLHuGVu15NG8xbCQ8yerKgMcvuUn2kZul02AvSXPkD3BWBY/i4YwU2/LvrFEZUeJppc ZS4gsXuMfnW+LaWjmqgNTiBxM65548wroBcqfTrvuaN5DXFaXfl9D0YQ7oo8aOaz3AGs ihnQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=IPEZG1UTOCdMILrBYHfNzu5EIxiMBByUqdY5jycPoxc=; b=DoPEEBpHc+wp5W/K3/iuUTcdEiuJZKH8u7t50d6Ms44IyGNCcH4K7jkN2u+Bk3xr1L 96mtpoE5NpwzLxIRDiFSkYThCW6w4RcVoDtoMCjh5tKN9pBEChf4Q8r8x0Ifj4uW8ePQ mfUsakpU7hfaUdI4Ub2gptOON58lkNZWVxyJ2gZz7FtkcWW/GNnEiEseM6DuIjMILOVa J0g2Fx0/MulOzFdXYqLUACfam0Mp5RCYDXWiD8PSWETFROKEq1G49gVWYXvwzSgFwWG8 g5sMAHkLpkVDYRKrCfMtazPUK2RzvChXtZLiaUxa3YvaXfTSMgNjUXb1/RpMvJY2Mvpb C6jg== X-Gm-Message-State: AOAM530+N6Ov0wjotsAjZS1R0REy2TgHIFd/I8vzHdtpgskRkwSiju1L LUREQGmY+QAlWii+/QtAlM4Wl647qA== X-Google-Smtp-Source: ABdhPJyg/U09wdEAopvM6ev2T6v/23FdAJfCe329HDtgHDUz1zy3T2j76fZoYZFWx4+JOF4++xvH0Q== X-Received: by 2002:a17:90b:3850:: with SMTP id nl16mr3351886pjb.127.1634179336371; Wed, 13 Oct 2021 19:42:16 -0700 (PDT) Received: from piliu.users.ipa.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id m28sm818403pgl.9.2021.10.13.19.42.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 13 Oct 2021 19:42:15 -0700 (PDT) From: Pingfan Liu To: linux-kernel@vger.kernel.org Cc: Pingfan Liu , Petr Mladek , Andrew Morton , Wang Qing , "Peter Zijlstra (Intel)" , Santosh Sivaraj , linux-arm-kernel@lists.infradead.org Subject: [PATCHv3 2/4] kernel/watchdog_hld: Ensure CPU-bound context when creating hardlockup detector event Date: Thu, 14 Oct 2021 10:41:53 +0800 Message-Id: <20211014024155.15253-3-kernelfans@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211014024155.15253-1-kernelfans@gmail.com> References: <20211014024155.15253-1-kernelfans@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org hardlockup_detector_event_create() should create perf_event on the current CPU. Preemption could not get disabled because perf_event_create_kernel_counter() allocates memory. Instead, the CPU locality is achieved by processing the code in a per-CPU bound kthread. Add a check to prevent mistakes when calling the code in another code path. Signed-off-by: Pingfan Liu Cc: Petr Mladek Cc: Andrew Morton Cc: Wang Qing Cc: "Peter Zijlstra (Intel)" Cc: Santosh Sivaraj Cc: linux-arm-kernel@lists.infradead.org To: linux-kernel@vger.kernel.org --- kernel/watchdog_hld.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/kernel/watchdog_hld.c b/kernel/watchdog_hld.c index 247bf0b1582c..df010df76576 100644 --- a/kernel/watchdog_hld.c +++ b/kernel/watchdog_hld.c @@ -165,10 +165,13 @@ static void watchdog_overflow_callback(struct perf_event *event, static int hardlockup_detector_event_create(void) { - unsigned int cpu = smp_processor_id(); + unsigned int cpu; struct perf_event_attr *wd_attr; struct perf_event *evt; + /* This function plans to execute in cpu bound kthread */ + WARN_ON(!is_percpu_thread()); + cpu = raw_smp_processor_id(); wd_attr = &wd_hw_attr; wd_attr->sample_period = hw_nmi_get_sample_period(watchdog_thresh); -- 2.31.1