From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1422826AbeCBMlG (ORCPT ); Fri, 2 Mar 2018 07:41:06 -0500 Received: from heliosphere.sirena.org.uk ([172.104.155.198]:33072 "EHLO heliosphere.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1034295AbeCBMlD (ORCPT ); Fri, 2 Mar 2018 07:41:03 -0500 Date: Fri, 2 Mar 2018 12:40:50 +0000 From: Mark Brown To: Jernej =?utf-8?Q?=C5=A0krabec?= 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 Message-ID: <20180302124050.GF6255@sirena.org.uk> References: <2424862.oPtAVTfrB9@jernej-laptop> <63331816.68OamKINx1@jernej-laptop> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="phCU5ROyZO6kBE05" Content-Disposition: inline In-Reply-To: <63331816.68OamKINx1@jernej-laptop> X-Cookie: He who laughs last didn't get the joke. User-Agent: Mutt/1.9.3 (2018-01-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --phCU5ROyZO6kBE05 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Mar 01, 2018 at 11:23:57PM +0100, Jernej =C5=A0krabec wrote: > I removed parts of the code from the sun4i codec driver and interestingly= it=20 > doesn't crash if I remove following lines: > ret =3D 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... --phCU5ROyZO6kBE05 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAlqZRlEACgkQJNaLcl1U h9BgIgf/Q3GZOlQCfAnUF4m/v9NaH4QxNM0OA/bgzS8qZecbkX1umIBvadiVvQk2 5iUAggTvZY64JxScseXyAkR2/KnzUcrzn3wCzA+7tRbuHzAliU3hLw4ZKjJPjhPP 3MJ6D1S4OXijQBQV6ASWXU7D1IEWucfCo57SY1BVwCVuCXOy1UQixQrrRWbDG76e Epe/i0ZFTxzI2+v2xJF2b3JKf0KaIUKFeVOYo5XtGBMqPjyDJcaIIg9xyBt5Oz63 e9zNDJ+7zQ/ydK0eGNLKCB4GvPTKGFkddbgArI9GJnfrb4fEzaavaqif+4ub5qm1 0F+GgKNInRSl0+f0HaDQorBPVNHf9A== =6y1d -----END PGP SIGNATURE----- --phCU5ROyZO6kBE05--