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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 2B616C282C2 for ; Wed, 6 Feb 2019 11:46:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00B4920B1F for ; Wed, 6 Feb 2019 11:46:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730081AbfBFLqa (ORCPT ); Wed, 6 Feb 2019 06:46:30 -0500 Received: from mx0a-001ae601.pphosted.com ([67.231.149.25]:55560 "EHLO mx0b-001ae601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727080AbfBFLq2 (ORCPT ); Wed, 6 Feb 2019 06:46:28 -0500 Received: from pps.filterd (m0077473.ppops.net [127.0.0.1]) by mx0a-001ae601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x16BdHuG023808; Wed, 6 Feb 2019 05:45:48 -0600 Authentication-Results: ppops.net; spf=none smtp.mailfrom=ckeepax@opensource.cirrus.com Received: from mail1.cirrus.com (mail1.cirrus.com [141.131.3.20]) by mx0a-001ae601.pphosted.com with ESMTP id 2qfp5p8sut-1; Wed, 06 Feb 2019 05:45:48 -0600 Received: from EX17.ad.cirrus.com (unknown [172.20.9.81]) by mail1.cirrus.com (Postfix) with ESMTP id 899E8611C8B2; Wed, 6 Feb 2019 05:45:47 -0600 (CST) Received: from imbe.wolfsonmicro.main (198.61.95.81) by EX17.ad.cirrus.com (172.20.9.81) with Microsoft SMTP Server id 14.3.408.0; Wed, 6 Feb 2019 11:45:47 +0000 Received: from imbe.wolfsonmicro.main (imbe.wolfsonmicro.main [198.61.95.81]) by imbe.wolfsonmicro.main (8.14.4/8.14.4) with ESMTP id x16BjjKE024165; Wed, 6 Feb 2019 11:45:45 GMT Date: Wed, 6 Feb 2019 11:45:45 +0000 From: Charles Keepax To: Krzysztof Kozlowski CC: Sylwester Nawrocki , Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , , , "linux-samsung-soc@vger.kernel.org" , Marek Szyprowski Subject: Re: [PATCH] ASoC: dapm: Check for NULL widget in dapm_update_dai_unlocked Message-ID: <20190206114545.GR3837@imbe.wolfsonmicro.main> References: <20190205211622.GA5891@kozik-lap> <844c3f34-f7db-6b26-169a-994922367c78@samsung.com> <20190206100549.GO3837@imbe.wolfsonmicro.main> <20190206105955.GP3837@imbe.wolfsonmicro.main> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-12-10) X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1902060093 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 06, 2019 at 12:14:56PM +0100, Krzysztof Kozlowski wrote: > On Wed, 6 Feb 2019 at 12:00, Charles Keepax > wrote: > > > > On Wed, Feb 06, 2019 at 11:22:33AM +0100, Krzysztof Kozlowski wrote: > > > On Wed, 6 Feb 2019 at 11:05, Charles Keepax > > > wrote: > > > > > > > > DAIs linked to the dummy will not have an associated playback/capture > > > > widget, so we need to skip the update in that case. > > > > > > > > Fixes: 078a85f2806f ("ASoC: dapm: Only power up active channels from a DAI") > > > > Signed-off-by: Charles Keepax > > > > --- > > > > > > > > Ok so that all makes sense, this patch is probably the best fix? > > > > > > > > Thanks, > > > > Charles > > > > > > For this particular issue (NULL-pointer): > > > Reported-by: Krzysztof Kozlowski > > > Tested-by: Krzysztof Kozlowski > > > > > > However now I see bug sleeping in atomic context: > > > > > > [ 64.000828] BUG: sleeping function called from invalid context at > > > ../kernel/locking/mutex.c:908 > > > > Does this probably definitely get fixed by reverting my patch? > > It's just a bit odd as this seems to be complaining about a clock > > operation in i2s_trigger and I don't think my patch should have > > any affect on the trigger callback. It should get run from either > > the dai_link DAPM event or hw_params, neither of which should > > happen in an atomic context. > > Before this fixup, probably NULL pointer happened before any of this. > I tried it now few times and the possible deadlock and sleeping in > invalid context did not appear. It might be random/racy or totally > unrelated to your change. > Looking through I think this is an unrelated issue. Assuming the driver in question is (sound/soc/samsung/i2s.c). Inside i2s_trigger, there is a call to config_setup(i2s), which in turn will call clk_get_rate if i2s->quirks contains the flag QUIRK_NO_MUXPSR. The trigger callback can be made from an atomic context and clk_get_rate will take the prepare lock of the clock. The clock prepare lock is always a mutex which shouldn't be locked from an atomic context. So it seems like this will fail whenever that QUIRK_NO_MUXPSR flag is set, no idea what causes that to be set. It looks like this bug was introduced by this change: 647d04f8e07a ("ASoC: samsung: i2s: Ensure the RCLK rate is properly determined") Thanks, Charles