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 E47C1C433EF for ; Fri, 25 Feb 2022 05:07:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237434AbiBYFHj (ORCPT ); Fri, 25 Feb 2022 00:07:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43074 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230443AbiBYFHh (ORCPT ); Fri, 25 Feb 2022 00:07:37 -0500 Received: from mail-pl1-x629.google.com (mail-pl1-x629.google.com [IPv6:2607:f8b0:4864:20::629]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0E9216F956 for ; Thu, 24 Feb 2022 21:07:05 -0800 (PST) Received: by mail-pl1-x629.google.com with SMTP id c9so3873731pll.0 for ; Thu, 24 Feb 2022 21:07:05 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=JbA4uogSRFlFWYCTaeCRBG+DmJ6BBRvbCTJcEPNgbT4=; b=Ha/ZeC9h2KHOqwZ/jX/IYs/hGEk24Oxp0x8qRDPzcYKn3mbQr9Z83PeLTH5c+kTlcI s84kbd/kpe1nGhtbDsbbxf5XYTAJC6M4okwxxJcYr91962ivmJBkJtr8onNSdqiVCGIX Quyujg1J8nwaZFhjsJLpTjIhYCjdZsyP37RO8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=JbA4uogSRFlFWYCTaeCRBG+DmJ6BBRvbCTJcEPNgbT4=; b=sC2JlR8v5WvkO5hFRahjJ1IVdYsm9/gtBFxcXFemAToD8G0K0Fppd59/bkT1Ay4MfQ X4vCjbvrJTYeX8vUqntLoCUcoVJkn2+2WkLvYTVPuUj48dqcGj9lh19ZoCrSmhCHF+3e kPgzWDvmPZOi6Ndsovvi0iDNNRWsQMEqQu23qwo2f7ej1coz3657+Vho09MFvSVDswYD bDfB6s4KRCde3qGJ4c9W/LmtRQAVZN/wl058PpR+XoXkFgxvfBjK9a2xlCEBpHBKGN4J shg1Yz80Jp/po11djKS5xeuTuUewkI+7Lv8DQvdLWNEVnlz2P8f48eh/fZOC7HxBKt+2 5HGg== X-Gm-Message-State: AOAM532TycNRgHmvdPprQAl9w0FRwGklMvm5c/3QJf+sg01T9DDT27a5 6PyEjnBbyhsAHLfarkH8lYiXuA== X-Google-Smtp-Source: ABdhPJzx/VcXI5LCD6w+mRHT/iJBc+sp3EjRUNKol+ePPfnN0x1if1vvs1rM+9smOW5F2aWY/nWsfg== X-Received: by 2002:a17:902:ef4c:b0:14f:7548:dae3 with SMTP id e12-20020a170902ef4c00b0014f7548dae3mr5843206plx.92.1645765625389; Thu, 24 Feb 2022 21:07:05 -0800 (PST) Received: from google.com ([2401:fa00:8f:203:e94f:9f5e:13f6:a198]) by smtp.gmail.com with ESMTPSA id m11-20020a17090a3f8b00b001bc299e0aefsm7615801pjc.56.2022.02.24.21.07.03 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 24 Feb 2022 21:07:04 -0800 (PST) Date: Fri, 25 Feb 2022 14:07:00 +0900 From: Sergey Senozhatsky To: Steven Rostedt Cc: LKML , Petr Mladek , John Ogness , Sergey Senozhatsky Subject: Re: Strange output on the console Message-ID: References: <20220224230035.36547137@gandalf.local.home> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (22/02/25 13:58), Sergey Senozhatsky wrote: > On (22/02/24 23:00), Steven Rostedt wrote: > > I've been noticing that my tests have been spitting out strange output on > > the console. It would happen at boot up and then clear up. It looks like > > something screwed up with the serial timing. > > > > Attached is a dmesg of one of my test runs as an example. > > > > I've noticed this on both 32 bit and 64 bit x86. > > > > I haven't had time to look deeper into this, but I figured I let you know > > about it. > > > > And it always seems to happen right after: > > > > Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled > > > > Maybe this is a serial issue and not a printk one? :-/ > > Steven, did you notice this recently? > May I perhaps suggest git bisect? (sorry) On the off chance - do you have this revert in your kernel? commit 6a7b9f002eca6788d346c16a6ff0c218b41f8d1d Author: Greg Kroah-Hartman Date: Wed Jan 26 14:33:58 2022 +0100 Revert "tty: serial: Use fifo in 8250 console driver" This reverts commit 5021d709b31b8a14317998a33cbc78be0de9ab30. The patch is still a bit buggy, and this breaks some other hardware types. It needs to be resubmitted in a non-buggy way, and make sure the other hardware types also continue to work properly.