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 45F3FC433EF for ; Mon, 20 Jun 2022 10:14:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241161AbiFTKOC (ORCPT ); Mon, 20 Jun 2022 06:14:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44816 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241073AbiFTKNn (ORCPT ); Mon, 20 Jun 2022 06:13:43 -0400 Received: from mail-pj1-x1035.google.com (mail-pj1-x1035.google.com [IPv6:2607:f8b0:4864:20::1035]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 83CB113DEC for ; Mon, 20 Jun 2022 03:13:42 -0700 (PDT) Received: by mail-pj1-x1035.google.com with SMTP id g10-20020a17090a708a00b001ea8aadd42bso9882029pjk.0 for ; Mon, 20 Jun 2022 03:13:42 -0700 (PDT) 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:content-transfer-encoding:in-reply-to; bh=Z21gJDBz+/e/yL0nifaa2vwAc9o2edhVlm8S1yTu95I=; b=kcHTLg7RgJMawzs3S7C4B4EqaDwaQPnG43f+MF/r3Nbvp4D0tiyEPbITC3ta7I7o9I 9NXbOU7Jlqk7NbGLQzM/l/NcYVMP+0rwY2NVWafT/iY6aA7aONkwq/azSUiX//OGFCK7 Bdd/Elkc+sBGiWwFtChg5zS1k84HCK3HOurBw= 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:content-transfer-encoding :in-reply-to; bh=Z21gJDBz+/e/yL0nifaa2vwAc9o2edhVlm8S1yTu95I=; b=T6u/UiUA3S3HzQpv1l+8FRFgvSicrzciUnVl0Fed7Z1f65WiOcfpIrN6ym+UDo6BNw CbJuImZyj+lrFt7WKaBRJkYqwSA7dBOnAFtJCCD2VwSZT3IkQeJLTKiJdvp/GTL08m6B 6/spwQZU+A+qYqKe3Ir3k5fwfadjL7ftyA/3QcHwPNzWkF+aXn4oeCTz0ySUIvpezJj1 SIvg9+5AyGSlZaheGc1qN9ZY0Tk2JBrBzVam/d45n7pBs3eFS6iPplejvByadyePnsrK bDdalJkkFgVL1q9ZWdJG2KnTYpYtDDtKofREnBwIwcHXN7AKbCUkoyYRw1tfQz/YTozu ertQ== X-Gm-Message-State: AJIora/lLGuGdnR+45rHOwH05CQByrdWItdpuCHptHgOChDYnlsaX1aR jnA4dB1JShYY9mJUL5zMW8WYoQ== X-Google-Smtp-Source: AGRyM1vCJHuC2W4v8uRR42/q9Ryt22IoRnv4kwt7mVdSaglOa1POvPq65FmX0P0an779Z6e44wtZeg== X-Received: by 2002:a17:90b:33d2:b0:1ea:b599:9e89 with SMTP id lk18-20020a17090b33d200b001eab5999e89mr25913130pjb.88.1655720022020; Mon, 20 Jun 2022 03:13:42 -0700 (PDT) Received: from google.com ([240f:75:7537:3187:7080:f919:392f:bc5c]) by smtp.gmail.com with ESMTPSA id h4-20020a170902680400b001640aad2f71sm8294955plk.180.2022.06.20.03.13.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Jun 2022 03:13:41 -0700 (PDT) Date: Mon, 20 Jun 2022 19:13:37 +0900 From: Sergey Senozhatsky To: Marek =?iso-8859-1?Q?Beh=FAn?= Cc: Sergey Senozhatsky , John Ogness , Petr Mladek , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: Boot stall regression from "printk for 5.19" merge Message-ID: References: <20220619204949.50d9154d@thinkpad> <20220620120234.5a65ac97@thinkpad> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20220620120234.5a65ac97@thinkpad> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (22/06/20 12:02), Marek Behún wrote: > > On (22/06/19 20:49), Marek Behún wrote: > > [..] > > > causes a regression on arm64 (Marvell CN9130-CRB board) where the > > > system boot freezes in most cases (and is unusable until restarted by > > > watchdog), or, in some cases boots, but the console output gets mangled > > > for a while (the serial console spits garbage characters). > > > > Can you please try disabling console kthreads and see how the boot > > process goes? Just `return 0` from printk_activate_kthreads() (I think > > this should do the trick). > > This indeed makes the problem go away... Oh... OK. Didn't expect that :) > > > The garbage example: > > > > > > ... > > > [ 0.920951] raid6: using neon recovery algorithm > > > [ 0.921228] iommu: Default domain type: Translated > > > % > > > > > > gb@k+cFL/[ 4.954974] DSA: tree 0 setup > > > [ 4.955286] cfg80211: Loading compiled-in X.509 certificates for regulatory database > > > > This is pretty suspicious. I don't see how console kthreads would > > corrupt the output. I suspect that something else is going on, some > > memory corruption, etc. > > Maybe multiple threads are writing to serial registers, or something... That's possible. Console drivers usually should grab port->lock for write(), but maybe something is missing in the driver you use. What console driver are you using?