From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753087AbeCEVad convert rfc822-to-8bit (ORCPT ); Mon, 5 Mar 2018 16:30:33 -0500 Received: from mailoutvs4.siol.net ([213.250.19.137]:53125 "EHLO mail.siol.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932645AbeCEVa2 (ORCPT ); Mon, 5 Mar 2018 16:30:28 -0500 From: Jernej =?utf-8?B?xaBrcmFiZWM=?= To: Mark Brown Cc: kuninori.morimoto.gx@renesas.com, maxime.ripard@free-electrons.com, wens@csie.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, alsa-devel@alsa-project.org Subject: Re: [BUG] Kernel crash on Allwinner H3 due to sound core changes Date: Mon, 05 Mar 2018 22:30:23 +0100 Message-ID: <26212674.B0xcQEiVyd@jernej-laptop> In-Reply-To: <20180302124050.GF6255@sirena.org.uk> References: <2424862.oPtAVTfrB9@jernej-laptop> <63331816.68OamKINx1@jernej-laptop> <20180302124050.GF6255@sirena.org.uk> MIME-Version: 1.0 Content-Transfer-Encoding: 8BIT Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Dne petek, 02. marec 2018 ob 13:40:50 CET je Mark Brown napisal(a): > On Thu, Mar 01, 2018 at 11:23:57PM +0100, Jernej Škrabec wrote: > > I removed parts of the code from the sun4i codec driver and interestingly > > it doesn't crash if I remove following lines: > > > > ret = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, 0); > > if (ret) { > > > > dev_err(&pdev->dev, "Failed to register against DMAEngine\n"); > > goto err_assert_reset; > > > > } > > > > Is it possible that NULL pointer causes troubles somewhere down the line? > > Shouldn't be, that's just the configuration which is optional and not > what we're crashing trying to register, we can mostly configure things > by querying the capabilities of the DMA controller via the dmaengine API > these days. You're removing all the DMA support there so cutting out a > huge segment of the initialization of both this driver and the machine > driver. Other sunxi devices seem to be starting happily in -next so > there's something system dependent here... I enabled memory debugging and it seems that there is an issue caused by loading sun4i-codec driver and it is somehow connected to snd_dmaengine_pcm_unregister(). Here is relevant dmesg: https://pastebin.com/raw/80K9GPnB Does this tell anything? Best regards, Jernej