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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 4C1A0C43381 for ; Fri, 22 Mar 2019 18:52:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1388E218A2 for ; Fri, 22 Mar 2019 18:52:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727743AbfCVSww (ORCPT ); Fri, 22 Mar 2019 14:52:52 -0400 Received: from foss.arm.com ([217.140.101.70]:50800 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725999AbfCVSww (ORCPT ); Fri, 22 Mar 2019 14:52:52 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 7516015AB; Fri, 22 Mar 2019 11:52:51 -0700 (PDT) Received: from [10.1.196.50] (e108454-lin.cambridge.arm.com [10.1.196.50]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3E1DC3F71A; Fri, 22 Mar 2019 11:52:50 -0700 (PDT) Subject: Re: [ANNOUNCE] v5.0.3-rt1 To: Sebastian Andrzej Siewior , Thomas Gleixner Cc: LKML , linux-rt-users , Steven Rostedt , john.ogness@linutronix.de, Dave P Martin References: <20190320171511.icjhdlulgal2yeho@linutronix.de> From: Julien Grall Message-ID: <791056c4-3575-0bd8-031e-44d0e3b21e54@arm.com> Date: Fri, 22 Mar 2019 18:52:48 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190320171511.icjhdlulgal2yeho@linutronix.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Apologies for a possible stupid question. On 20/03/2019 17:15, Sebastian Andrzej Siewior wrote: > - Applied John Ogness' prinkt rework. One visible change is the > output during boot. Under the hood and for RT: By default, output > that is created at KERN_WARN[0] or higher is printed immediately if the > console supports "atomic" print (currently the 8250 driver does). > This output is printed immediately (and visible) even from IRQ-off > or preempt-disabled regions which wasn't the case earlier. This will > raise the latency at run-time *but* there should be no WARNING, > ERROR or PANIC messages at run-time on a fully working system. > Messages with lower severity are printed "later" by a kthread. Using 5.0.3-rt1, I get some warning message completely mangled with the rest of the output (e.g systemd message) but also between them. Some excerpt of a 500 lines lockdep warning (AFAICT the printk is not related to the printk code): [ 52.294547] 005: ... which became HARDIRQ-irq-unsafe at: [ 52.294553] 005: ... [ 52.294554] 005: lock_acquire+0xf8/0x318 [ OK ] Reached target t_spin_lock+0x48/0x70 lock_acquire+0xf8/0x318 [0;1;39mRemote File Systems.[ 52.294570] 005: iommu_dma_map_msi_msg+0x5c/0x1 [ 52.296824] 005: CPU: 5 PID: 2108 Comm: ip Not tainted 5.0.3-rt1-00007-g42ede 9a0fed6 #4312] 005: __sys_sendmsg+0x68/0xb8 I understand the new series add support for "atomic" print. So I am wondering whether this issue is related to it? Is there any advice to prevent the mangling? Cheers, -- Julien Grall