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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 EBA1EC433F5 for ; Wed, 15 Sep 2021 03:51:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D12EE60F25 for ; Wed, 15 Sep 2021 03:51:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236287AbhIODwv (ORCPT ); Tue, 14 Sep 2021 23:52:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236293AbhIODws (ORCPT ); Tue, 14 Sep 2021 23:52:48 -0400 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DFADEC061764 for ; Tue, 14 Sep 2021 20:51:29 -0700 (PDT) Received: by mail-pg1-x530.google.com with SMTP id w8so1370470pgf.5 for ; Tue, 14 Sep 2021 20:51:29 -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=kfimq1QM2ub4RCzsUMT7wxbrZt86ZSDXRQu91Wlfp5Q=; b=JDdFqobRqLt1C9EL/bCPgSLe+1r6014LFaqefAW+z7gCruWRHNhVxaeVuhtSMJhVAG 7d9io1vBFiLJrDkxGuRa2hFbGwDl286hlO/XliN6s5UHH3fJVG2/lsJ7LOgZ9yYIX9hc +oxEpNpU979BSNbcSGqj+jeD9xZ4CqDSWYPzfOigKT10PKMQ/C+EaiJF9YRZMMblaQTa AQA5vpD9q2nKDC/pZablhBrkzQ1yc8xJXAHzH1jCKkkX8k521flVQhBXszmmnPdpUMgG b6R9nEqfTq2KocQo1Od9sIcR2oY4E1BuzoOLgBrQ10njQCdAwbdpSh/OvgNe6GHCruAs Oojg== 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=kfimq1QM2ub4RCzsUMT7wxbrZt86ZSDXRQu91Wlfp5Q=; b=YFuh41ZmeZyS+6uAaJDpoGM9ApXdP/7rcdyOando9JE8gP5aJEdxMme6XkzJbjN1jQ 7oRBbr/Qjs1+2By7qlHqS9YJWzLKq70LRCcF0zpj8UenU/ElQhnC6aTbZ2ras/KSYOyJ GeI8PGDAG1AVr7axedVqbhbGWl4bxVs+UhWhGSPkJYzV5VRsDETKjUcSdtCsmwMOax74 tDs+0WbaYyKZgvu43iRO2T5R6qAts7WNh/OFvad7cQ17zHvl5wqKuiM4z2+INQpxh8q9 ZrRDFfgnZlduvZs0KUykngb3LJpYf51Vj9dLsRwdPNuSV+FjxNTz/sfBeCveWl2hCzTm vPCw== X-Gm-Message-State: AOAM53070OnURQl/tsmSxpCXiiws7UeBhUOiXSWb7ZZf6+8btA8gFxGi pZK3SqzbZLirHNGnk7gGiP0eU8mKKA== X-Google-Smtp-Source: ABdhPJxtTw/h8SXKYy8qHRGgdZjwIdVKXkNtI9YCxrUXlKu0gqKpKdwB6O6AaDhMQY8wAX9yT6jydw== X-Received: by 2002:a63:4607:: with SMTP id t7mr18569791pga.332.1631677889263; Tue, 14 Sep 2021 20:51:29 -0700 (PDT) Received: from piliu.users.ipa.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id x13sm8602357pfp.133.2021.09.14.20.51.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 14 Sep 2021 20:51:29 -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 , Sumit Garg , Will Deacon , Mark Rutland Subject: [PATCH 2/5] kernel/watchdog_hld: clarify the condition in hardlockup_detector_event_create() Date: Wed, 15 Sep 2021 11:51:00 +0800 Message-Id: <20210915035103.15586-3-kernelfans@gmail.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210915035103.15586-1-kernelfans@gmail.com> References: <20210915035103.15586-1-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() indirectly calls kmem_cache_alloc_node(), which is blockable. So here, the really planned context is is_percpu_thread(). Signed-off-by: Pingfan Liu Cc: Petr Mladek Cc: Andrew Morton Cc: Wang Qing Cc: "Peter Zijlstra (Intel)" Cc: Santosh Sivaraj Cc: Sumit Garg Cc: Will Deacon Cc: Mark Rutland 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..6876e796dbf5 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 */ + BUG_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