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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_PASS 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 0968BC43387 for ; Tue, 15 Jan 2019 03:11:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CFBF220659 for ; Tue, 15 Jan 2019 03:11:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727772AbfAODLW (ORCPT ); Mon, 14 Jan 2019 22:11:22 -0500 Received: from mga11.intel.com ([192.55.52.93]:5767 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726769AbfAODLV (ORCPT ); Mon, 14 Jan 2019 22:11:21 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga007.fm.intel.com ([10.253.24.52]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Jan 2019 19:08:19 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,480,1539673200"; d="scan'208";a="114721324" Received: from unknown (HELO [10.254.5.67]) ([10.254.5.67]) by fmsmga007.fm.intel.com with ESMTP; 14 Jan 2019 19:08:16 -0800 Subject: Re: [alsa-devel] [PATCH] ASoC: soc-core: Fix null pointer dereference in soc_find_component To: Mark Brown Cc: rohkumar@qti.qualcomm.com, alsa-devel@alsa-project.org, bgoswami@codeaurora.org, vinod.koul@linaro.org, linux-kernel@vger.kernel.org, plai@codeaurora.org, tiwai@suse.com, lgirdwood@gmail.com, Ajit Pandey , Liam Girdwood , Rohit kumar , asishb@codeaurora.org, srinivas.kandagatla@linaro.org References: <1547194442-1487-1-git-send-email-rohitkr@codeaurora.org> <4886ed21-65d2-159d-afcd-bb26dcde636e@linux.intel.com> <20190115000610.GM11073@sirena.org.uk> From: Pierre-Louis Bossart Message-ID: <163e0e01-fcf9-6f9f-4317-e71bd9cb47b1@linux.intel.com> Date: Mon, 14 Jan 2019 21:08:15 -0600 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <20190115000610.GM11073@sirena.org.uk> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/14/19 6:06 PM, Mark Brown wrote: > On Fri, Jan 11, 2019 at 03:49:08PM -0600, Pierre-Louis Bossart wrote: > >> Adding some traces I can see that the the platform name we use doesn't seem >> compatible with your logic. All the Intel boards used a constant platform >> name matching the PCI ID, see e.g. [1], which IIRC is used to bind >> components. Liam, do you recall in more details if this is really required? > That's telling me that either snd_soc_find_components() isn't finding > components in the same way that we do when we bind things which isn't > good or we're binding links without having fully matched everything on > the link which also isn't good. > > Without a system that shows the issue I can't 100% confirm but I think > it's the former - I'm fairly sure that those machines are relying on the > component name being initialized to fmt_single_name() in > snd_soc_component_initialize(). That is supposed to wind up using > dev_name() (which would be the PCI address for a PCI device) as the > basis of the name. What I can't currently see is how exactly that gets > bound (or how any of the other links avoid trouble for that matter). We > could revert and push this into cards but I would rather be confident > that we understand what's going on, I'm not comfortable that we aren't > just pushing the breakage around rather than fixing it. Can someone > with an x86 system take a look and confirm exactly what's going on with > binding these cards please? I am actually not sure at all why we need the platform_name to be set in Intel machine drivers. I ran a 5mn experiment with SOF and we completely ignore what is set by machine drivers, it's overridden by the component name:             dev_info(card->dev, "info: override FE DAI link %s\n",                  card->dai_link[i].name);             /* override platform component */             if (snd_soc_init_platform(card, dai_link) < 0) {                 dev_err(card->dev, "init platform error");                 continue;             }             pr_err("plb: platform_name was %s, now %s\n",                    dai_link->platform->name,                    component->name);             dai_link->platform->name = component->name; existing machine driver (info is incorrect btw, should be BE DAI link) [   36.628466] bxt-pcm512x bxt-pcm512x: info: override FE DAI link SSP5-Codec [   36.628469] plb: platform_name was sof-audio, now sof-audio [   36.628772] bxt-pcm512x bxt-pcm512x: info: override FE DAI link iDisp1 [   36.628773] plb: platform_name was 0000:00:0e.0, now sof-audio [   36.629111] bxt-pcm512x bxt-pcm512x: info: override FE DAI link iDisp2 [   36.629112] plb: platform_name was 0000:00:0e.0, now sof-audio [   36.629422] bxt-pcm512x bxt-pcm512x: info: override FE DAI link iDisp3 [   36.629423] plb: platform_name was 0000:00:0e.0, now sof-audio machine driver with all platform_name commented out, no regression at all. [   15.839652] sof-audio sof-audio: created machine bxt-pcm512x [   15.846990] bxt-pcm512x bxt-pcm512x: info: override FE DAI link SSP5-Codec [   15.846995] plb: platform_name was snd-soc-dummy, now sof-audio [   15.847325] bxt-pcm512x bxt-pcm512x: info: override FE DAI link iDisp1 [   15.847326] plb: platform_name was snd-soc-dummy, now sof-audio [   15.847657] bxt-pcm512x bxt-pcm512x: info: override FE DAI link iDisp2 [   15.847658] plb: platform_name was snd-soc-dummy, now sof-audio [   15.847974] bxt-pcm512x bxt-pcm512x: info: override FE DAI link iDisp3 [   15.847974] plb: platform_name was snd-soc-dummy, now sof-audio I checked for a bit longer with the Skylake driver, I also couldn't see a difference with or without the platform_name set. diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c index 0462b3ec977a..0fdf99ec17cd 100644 --- a/sound/soc/soc-core.c +++ b/sound/soc/soc-core.c @@ -918,7 +918,7 @@ static int soc_bind_dai_link(struct snd_soc_card *card,                 if (!snd_soc_is_matching_component(dai_link->platform,                                                    component))                         continue; - +               pr_err("plb: binding with component_name %s \n", component->name);                 snd_soc_rtdcom_add(rtd, component);         } @@ -1041,6 +1041,8 @@ static int snd_soc_init_platform(struct snd_soc_card *card,                 if (!platform)                         return -ENOMEM; +               pr_err("plb: %s: plaform->name set to %s\n", __func__, +                      dai_link->platform_name);                 dai_link->platform      = platform;                 platform->name          = dai_link->platform_name;                 platform->of_node       = dai_link->platform_of_node; [    1.345143] plb: snd_soc_init_platform: plaform->name set to 0000:00:1f.3 [    1.345148] skl_hda_dsp_generic skl_hda_dsp_generic: ASoC: binding CNL Audio [    1.345151] plb: binding with component_name 0000:00:1f.3 [    1.345153] plb: snd_soc_init_platform: plaform->name set to 0000:00:1f.3 [    1.345154] skl_hda_dsp_generic skl_hda_dsp_generic: ASoC: binding CNL HDMI1 [    1.345155] plb: binding with component_name 0000:00:1f.3 [    1.345157] plb: snd_soc_init_platform: plaform->name set to 0000:00:1f.3 [    1.345158] skl_hda_dsp_generic skl_hda_dsp_generic: ASoC: binding CNL HDMI2 [    1.345159] plb: binding with component_name 0000:00:1f.3 [    1.345161] plb: snd_soc_init_platform: plaform->name set to 0000:00:1f.3 [    1.345162] skl_hda_dsp_generic skl_hda_dsp_generic: ASoC: binding CNL HDMI3 [    1.345163] plb: binding with component_name 0000:00:1f.3 [    1.349607] plb: snd_soc_init_platform: plaform->name set to (null) [    1.349613] skl_hda_dsp_generic skl_hda_dsp_generic: ASoC: binding CNL Audio [    1.349617] plb: binding with component_name snd-soc-dummy [    1.349619] plb: binding with component_name snd-soc-dummy [    1.349621] plb: snd_soc_init_platform: plaform->name set to (null) [    1.349623] skl_hda_dsp_generic skl_hda_dsp_generic: ASoC: binding CNL HDMI1 [    1.349625] plb: binding with component_name snd-soc-dummy [    1.349626] plb: binding with component_name snd-soc-dummy [    1.349628] plb: snd_soc_init_platform: plaform->name set to (null) [    1.349631] skl_hda_dsp_generic skl_hda_dsp_generic: ASoC: binding CNL HDMI2 [    1.349632] plb: binding with component_name snd-soc-dummy [    1.349633] plb: binding with component_name snd-soc-dummy [    1.349635] plb: snd_soc_init_platform: plaform->name set to (null) [    1.349638] skl_hda_dsp_generic skl_hda_dsp_generic: ASoC: binding CNL HDMI3 [    1.349639] plb: binding with component_name snd-soc-dummy [    1.349641] plb: binding with component_name snd-soc-dummy Audio playback works in both cases. The funny thing is that the list of components is right in /sys/kernel/debug/asoc. My guess is that the required PCI component is already added when the platform_name is used in soc_bind_dai_link() and snd_soc_rtdcom_add() does nothing for the back-end, so the dailink platform_name has actually zero influence on the outcome. Another way to look at it is that we already provide the dai_link->cpu_dai_name which is enough for soc_bind_dai_link() to find the relevant component and as a result the dailink->platform_name seems redundant/unnecessary. I am using the conditional here since this part of the code (Intel driver included) seems to work by accident rather than by design, and we'd need a set of additional tests before removing these hard-coded initializations. Does this help?