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=-3.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,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 AFF01C4363A for ; Mon, 5 Oct 2020 19:40:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 49FD02100A for ; Mon, 5 Oct 2020 19:40:55 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="kMo4t+R9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729474AbgJETkz (ORCPT ); Mon, 5 Oct 2020 15:40:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729302AbgJETky (ORCPT ); Mon, 5 Oct 2020 15:40:54 -0400 Received: from mail-qt1-x829.google.com (mail-qt1-x829.google.com [IPv6:2607:f8b0:4864:20::829]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8A7A2C0613CE for ; Mon, 5 Oct 2020 12:40:54 -0700 (PDT) Received: by mail-qt1-x829.google.com with SMTP id q26so5426413qtb.5 for ; Mon, 05 Oct 2020 12:40:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=kREpN8rcJJLtCBTQUYiHgZjJZAnrY0I4F3PH4U9ndTE=; b=kMo4t+R9fnVLvEtCqYPLlPZma/Q/Mulwc69kjbzVApfmJrgQCvDwMx4/DBVyAWfrTA BgP2/kRofzrSph4Izijw5wVMW+ARzmMpP0u7Na4lopHcxBqTgBABUKPCEwdjxOV8CSnk dnrfxryVRXg5J7wB1zLzu9xmM6N50vUI9gKJyglDOC70U3tgwbkjfaiEjT1GLqYEZyEA 2DkbugZSeplRYZeP8b0cL7/p9qjcipDN2dI1f/qcZP3QbJIeXSUsDzmNPaRoqKSTrVBr qFcFIFiLGe02O3VLc8q42EVt2on7QQEnUhlc7Sn5xjsliOkfhssoydk81fRRMklRJhlf EU/Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=kREpN8rcJJLtCBTQUYiHgZjJZAnrY0I4F3PH4U9ndTE=; b=ZMtRqdwRtgd/MeCtYEwQIq8+HXBMWuIsy3r3t3uaEvVrZL8rgChQdG/GfQKaTfSUBg H6vspPeZP2dlCOJsO5MhiXGA2c3BnaFgceZlviwMhtO8sUVgSxxjE9BkUiKKi4gBVZzU XZo7IcHuIlGWbfrrsu3WmKteA8V+eFY3TBp3lbASan9754yqRyNKFT9wlw8SDe47uMdF er4Ec6M1+2hx4AJeRjdwaH5Q5vLMtiRJ5zkEcXQkRpDqBXuuO7hj6g9NxxYl8ZyWCyCs 01AXtfYHg27Ig2i7YewME/frlpgb6xIPmLg28nCrf8m6RskdL84YjID++SC5hSqAbOli 7DdA== X-Gm-Message-State: AOAM530APFinn1oPmiZIFLtWIX5AIV7o8HVg7azvOknuVn38XhupU6Q7 4eUzNholdmksoyEszYESoWEkm2qjjAOk7TYWaco= X-Google-Smtp-Source: ABdhPJyvX7lDuoiNmFHAM2F3zm+jL3v+xUUsrEJOv1TZtXDkzYPe2PT+cQ6EZ9Uy0GZaoYogpCKZGeiUx29MLrXFUPM= X-Received: by 2002:ac8:6a06:: with SMTP id t6mr1548767qtr.1.1601926853729; Mon, 05 Oct 2020 12:40:53 -0700 (PDT) MIME-Version: 1.0 References: <20200925095715.poa62noo7dq2zyyp@linux-8csb> <20200925151635.dar46x7shgu4nqms@linutronix.de> In-Reply-To: <20200925151635.dar46x7shgu4nqms@linutronix.de> From: Richard Weinberger Date: Mon, 5 Oct 2020 21:40:42 +0200 Message-ID: Subject: Re: Debugging reboot freeze To: Sebastian Andrzej Siewior Cc: Aaron Marcher , rt-users , Peng Fan Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-rt-users@vger.kernel.org Sebastian, On Fri, Sep 25, 2020 at 5:18 PM Sebastian Andrzej Siewior wrote: > - try a later kernel (v5.9) > - implement ->write_atomic() and make sure the output goes to > printk_emergency() (so the output hits the uart right away). > - enable lockdep and check what explodes. thanks a lot for your suggestions. Testing on 5.9 will happen soon (custom hardware, you know the dance...). I'm looking right now into implementing >write_atomic() for the i.mx8. What we found so far: The root of the problem seems to be in ci_hdrc_remove_device(), called by ci_hdrc_imx_shutdown(). With ci_hdrc_imx_driver.shutdown being a no-op, reboot works fine. Peng Fan, does this ring a bell? The issue seems to be timing sensitive, enabling lockdep makes the problem go away. :-( -- Thanks, //richard