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=-5.2 required=3.0 tests=BAYES_00, BUG6152_INVALID_DATE_TZ_ABSURD,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS,INVALID_DATE_TZ_ABSURD,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 D3AADC433E0 for ; Wed, 27 Jan 2021 23:32:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9920F64D7F for ; Wed, 27 Jan 2021 23:32:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235609AbhA0Xb4 (ORCPT ); Wed, 27 Jan 2021 18:31:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48240 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233522AbhA0XbR (ORCPT ); Wed, 27 Jan 2021 18:31:17 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 71FD8C0617A7 for ; Wed, 27 Jan 2021 15:29:09 -0800 (PST) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1611790146; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ovKlPzpKCMynzgFtEXCUWBxt30oNgDe6PQkZXpXltUA=; b=C/tBOjYGSKvMIq4ciJOkKiAxjDcyNQ+81R7SWA7tWAwRiKX0TGdmh/WVQiihEScPSNcXc+ C1cYSr9oAAGuTDX9K4VQtWoSwIAYYJABGO7IBcHFL+a0aTQjJ5uMgvlnfHZSQ1zcRsJKvG X7a1IOxKQpM/exo1QP/N/AHDhot8ROujrqwyA1AdTMEiOaSQMEDXiyJ8GTGyqkpyvD/PwO xV/36kZfOPBaQmXNecESa69z2ovJB4aZ5grm60n5uY5sbVeOeXu4r5NCjHWV4rwNv6qmLJ TspgAK3key6s8A8KsWqzFdq/ix8f1nB9gQf8LYciO3aT8UD4Pvq9BDIvBq4h4w== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1611790146; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ovKlPzpKCMynzgFtEXCUWBxt30oNgDe6PQkZXpXltUA=; b=JJFCLAa8lWBu1muEWqTMVrgiMNXfffjAYOQnL5m1DE3P0ielD0T3ncr+RZTA83IQXkZc2D hF046Xs3itYu1ICA== To: Sergey Senozhatsky , Petr Mladek Cc: kernel test robot , Sergey Senozhatsky , LKML , lkp@lists.01.org, lkp@intel.com, zhengjun.xing@linux.intel.com Subject: Re: [printk] b031a684bf: INFO:rcu_tasks_detected_stalls_on_tasks In-Reply-To: <87bldaaxcc.fsf@jogness.linutronix.de> References: <20210122081311.GA12834@xsang-OptiPlex-9020> <87bldaaxcc.fsf@jogness.linutronix.de> Date: Thu, 28 Jan 2021 00:35:06 +0106 Message-ID: <878s8eari5.fsf@jogness.linutronix.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2021-01-27, John Ogness wrote: > I was finally able to trigger this by using my workstation Well, I don't know how reliably I can trigger this. I think my time will be better spent getting lkp to trigger, since that shows to be reliable. It took me an hour to trigger this one and I have the feeling I got lucky with it. [ 1854.183816] INFO: rcu_tasks detected stalls on tasks: [ 1854.184502] 0000000036ce200f: .. nvcsw: 0/0 holdout: 1 idle_cpu: -1/1 [ 1854.185234] task:dd state:R running task stack: 0 pid:19891 ppid: 668 flags:0x00000000 [ 1854.185273] Call Trace: [ 1854.185275] __schedule+0xfa9/0x1056 [ 1854.185283] ? firmware_map_remove+0x172/0x172 [ 1854.185300] ? ksys_write+0x147/0x180 [ 1854.185304] schedule+0x170/0x1e3 [ 1854.185307] exit_to_user_mode_prepare+0x27/0xac [ 1854.185312] syscall_exit_to_user_mode+0x41/0x4f [ 1854.185316] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1854.185321] RIP: 0033:0x7f99bf52fc00 [ 1854.185324] RSP: 002b:00007ffd75722bf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 1854.185328] RAX: 0000000000000001 RBX: 00007f99bfa1b690 RCX: 00007f99bf52fc00 [ 1854.185331] RDX: 0000000000000001 RSI: 0000560056ce3010 RDI: 0000000000000001 [ 1854.185335] RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 [ 1854.185338] R10: 00007ffd757229c0 R11: 0000000000000246 R12: 0000560056ce3010 [ 1854.185341] R13: 0000000000000001 R14: 0000560056ce3010 R15: 0000560056ce3010 To generate syscalls and interrupts, "dd" was doing: dd if=/dev/zero bs=1 count=100000000 | nc 10.0.2.2 12345 I'm not even sure how to go about debugging this. The only printk load I can really see are the: "tasks-torture:torture_onoff task: online 0 failed: errno -5" error messages. But they are only occurring at a rate of 40-50 per second. They are coming from the pr_alert() in kernel/torture.c:174, so it should still be hitting spinlocks (either from the console driver or @console_owner_lock). I will re-focus on reproducing this with lkp. John Ogness