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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 3FA61C47256 for ; Fri, 1 May 2020 03:22:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1EA072073E for ; Fri, 1 May 2020 03:22:47 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="Y9fzkmZF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728143AbgEADWq (ORCPT ); Thu, 30 Apr 2020 23:22:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727889AbgEADWp (ORCPT ); Thu, 30 Apr 2020 23:22:45 -0400 Received: from mail-vs1-xe43.google.com (mail-vs1-xe43.google.com [IPv6:2607:f8b0:4864:20::e43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0CD25C035494 for ; Thu, 30 Apr 2020 20:22:44 -0700 (PDT) Received: by mail-vs1-xe43.google.com with SMTP id z1so5626109vsn.11 for ; Thu, 30 Apr 2020 20:22:43 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=Q8zKtdoBSqXZ/3UpfSxQ1WF/iLXzd6iSL9Ugo4OLKbs=; b=Y9fzkmZF4Md1uRBhwT6euvierZyC/AKxTpDXu7Dk6WxVg3y0tu2eqANLfaTNYAsVFj a81x+n+mdsfibDz+uGIqYRmjeK1yWKSgBb9Bd7t+s6+aEnVKOf0kz1o4Jv7DaTk8gl/X cOzvNmnegodNx/G1pM8yRemny6IiD33rdapu8= 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:content-transfer-encoding; bh=Q8zKtdoBSqXZ/3UpfSxQ1WF/iLXzd6iSL9Ugo4OLKbs=; b=O18rTMJrQp7aRas5I4ODmqTS1jstEXRTOreMvDoRGOvwZjown+IZ7YC5fKtVYvj9QC 4QPdb5kFIQbMpKDAkiRcwiNDKkrj31wzvT++Cva7Hlk7JHAReXt0CRHUiDiIICH7KEGK pXCApBZX8cikMK9mI+YUVDF4r9y3mJ9b621CNtS6Xa11VZXcSk3PEFYtGHwshUjZH9ZQ 50FgBcNZUSQYl6u7HHZzeYFXqtK8WmayNdMQck3KYCh3f4qsypG0H+cEpgw1eYoS98FI YiMe+qiAxEpSSL4i1Zjlv4aDg3NziXGeYVE+2gzjgmxzzkRSAr1jI/bz7Ps2eB2Txv2G wEDg== X-Gm-Message-State: AGi0PuZsfibSX5Ima1AsgVDs9yNgiJQU+Es6Ih9ZLaMKIzosgnX9OVME 0uwm0f5+QZ/gB8AjmouGeWtjQTZaQxgFmLnN7d2N/g== X-Google-Smtp-Source: APiQypJsraivejPpvRInzgNAufivQ4doWR5sXSDjgvYk3ULfpSlPjvnG37hBADVwXE3SvlCNmHE9Ng6wkox5Wu0CQxc= X-Received: by 2002:a67:79d0:: with SMTP id u199mr1728674vsc.115.1588303363042; Thu, 30 Apr 2020 20:22:43 -0700 (PDT) MIME-Version: 1.0 References: <20200428110253.1.I926f6741079cafb04ecb592130aef75b24ad31ae@changeid> <20200501005609.GA131713@google.com> In-Reply-To: <20200501005609.GA131713@google.com> From: Daniil Lunev Date: Fri, 1 May 2020 13:22:31 +1000 Message-ID: Subject: Re: [PATCH] platform/chrome: cros_ec_typec: Handle NULL EC pointer during probe. To: Prashant Malani Cc: Enric Balletbo i Serra , LKML , Benson Leung , Guenter Roeck Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Prashant, I do not think it is present. Thinking about it, I do not think it shall be an issue on any released device as it will have either a firmware which wouldn't even trigger the typec probe or the one after the hierarchy fix. Likely I just got a firmware which was somewhere in between those two (As I did some unrelated FW testing). So, yes, probably putting this upstream is not necessary, though IMO more sanity checks - especially on non-critical run-once paths - are always better than having a kernel panic lingering around the corner, not like I am insisting on pushing the patch though with all the info, up to Enric. Cheers, Daniil On Fri, May 1, 2020 at 10:56 AM Prashant Malani wrot= e: > > Hi Daniil, > > On Fri, May 01, 2020 at 10:15:18AM +1000, Daniil Lunev wrote: > > On the official revision of coreboot for hatch it doesn't even try to > > load Type C. However it gives some warning messages from > > cros-usbpd-notify-acpi about EC, So I wonder why the check of the same > > type is not appropriate in the typec driver? > > I think the difference is that GOOG0003 is already present on shipped / > official versions of coreboot (so not having that check can cause > existing release images/devices to crash), whereas for GOOG0014 that is /= isn't the case. > > Is GOOG0014 present on the official release coreboot image for this > device? If so, what's its path (/sys/bus/acpi/devices//path) ? > > Best regards, > > -Prashant > > > > ../chrome/cros_usbpd_notify.c > > > > /* Get the EC device pointer needed to talk to the EC. */ > > ec_dev =3D dev_get_drvdata(dev->parent); > > if (!ec_dev) { > > /* > > * We continue even for older devices which don't have the > > * correct device heirarchy, namely, GOOG0003 is a child > > * of GOOG0004. > > */ > > dev_warn(dev, "Couldn't get Chrome EC device pointer.\n"); > > } > > > > > > # dmesg > > ... > > [ 8.513351] cros-ec-spi spi-PRP0001:02: EC failed to respond in time > > [ 8.722072] cros-ec-spi spi-PRP0001:02: EC failed to respond in time > > [ 8.729271] cros-ec-spi spi-PRP0001:02: Cannot identify the EC: erro= r -110 > > [ 8.736966] cros-ec-spi spi-PRP0001:02: cannot register EC, > > fallback to spidev > > [ 8.767017] cros_ec_lpcs GOOG0004:00: Chrome EC device registered > > [ 8.807537] cros-usbpd-notify-acpi GOOG0003:00: Couldn't get Chrome > > EC device pointer. > > ... > > > > On Fri, May 1, 2020 at 2:17 AM Prashant Malani w= rote: > > > > > > Hi Enric, > > > > > > On Thu, Apr 30, 2020 at 8:26 AM Enric Balletbo i Serra > > > wrote: > > > > > > > > Hi Prashant, > > > > > > > > On 30/4/20 2:43, Prashant Malani wrote: > > > > > On Wed, Apr 29, 2020 at 5:38 PM Daniil Lunev wrote: > > > > >> > > > > >> [to make it appear on the mailing list as I didn't realize I was= in > > > > >> hypertext sending mode] > > > > >> > > > > >> On Thu, Apr 30, 2020 at 10:11 AM Daniil Lunev wrote: > > > > >>> > > > > >>> Hi Enric. > > > > >>> I encountered the issue on a Hatch device when trying running 5= .4 kernel on that. After talking to Prashant it seems that any device with = coreboot built before a certain point (a particular fix for device hierarch= y in ACPI tables of Chrome devices which happened in mid-April) will not be= able to correctly initialize the driver and will get a kernel panic trying= to do so. > > > > > > > > > > A clarifying detail here: This should not be seen in any current > > > > > *production* device. No prod device firmware will carry the erron= eous > > > > > ACPI device entry. > > > > > > > > > > > > > Thanks for the clarification. Then, I don't think we need to upstre= am this. This > > > > kind of "defensive-programming" it's not something that should matt= er to upstream. > > > > > > Actually, on second thought, I am not 100% sure about this: > > > Daniil, is the erroneous ACPI device on a *production* firmware for > > > this device (I'm not sure about the vintage of that device's BIOS)? > > > > > > My apologies for the confusion, Enric and Daniil; but would be good t= o > > > get clarification from Daniil. > > > > > > Best regards, > > > > > > > > Thanks, > > > > Enric > > > > > > > > > > > > >>> Thanks, > > > > >>> Daniil > > > > >>> > > > > >>> On Thu, Apr 30, 2020 at 7:58 AM Enric Balletbo i Serra wrote: > > > > >>>> > > > > >>>> Hi Daniil, > > > > >>>> > > > > >>>> Thank you for the patch. > > > > >>>> > > > > >>>> On 28/4/20 3:02, Daniil Lunev wrote: > > > > >>>>> Missing EC in device hierarchy causes NULL pointer to be retu= rned to the > > > > >>>>> probe function which leads to NULL pointer dereference when t= rying to > > > > >>>>> send a command to the EC. This can be the case if the device = is missing > > > > >>>>> or incorrectly configured in the firmware blob. Even if the s= ituation > > > > >>>> > > > > >>>> There is any production device with a buggy firmware outside? = Or this is just > > > > >>>> for defensive programming while developing the firmware? Which= device is > > > > >>>> affected for this issue? > > > > >>>> > > > > >>>> Thanks, > > > > >>>> Enric > > > > >>>> > > > > >>>>> occures, the driver shall not cause a kernel panic as the con= dition is > > > > >>>>> not critical for the system functions. > > > > >>>>> > > > > >>>>> Signed-off-by: Daniil Lunev > > > > >>>>> --- > > > > >>>>> > > > > >>>>> drivers/platform/chrome/cros_ec_typec.c | 5 +++++ > > > > >>>>> 1 file changed, 5 insertions(+) > > > > >>>>> > > > > >>>>> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/driver= s/platform/chrome/cros_ec_typec.c > > > > >>>>> index 874269c07073..30d99c930445 100644 > > > > >>>>> --- a/drivers/platform/chrome/cros_ec_typec.c > > > > >>>>> +++ b/drivers/platform/chrome/cros_ec_typec.c > > > > >>>>> @@ -301,6 +301,11 @@ static int cros_typec_probe(struct platf= orm_device *pdev) > > > > >>>>> > > > > >>>>> typec->dev =3D dev; > > > > >>>>> typec->ec =3D dev_get_drvdata(pdev->dev.parent); > > > > >>>>> + if (!typec->ec) { > > > > >>>>> + dev_err(dev, "Failed to get Cros EC data\n"); > > > > >>>>> + return -EINVAL; > > > > >>>>> + } > > > > >>>>> + > > > > >>>>> platform_set_drvdata(pdev, typec); > > > > >>>>> > > > > >>>>> ret =3D cros_typec_get_cmd_version(typec); > > > > >>>>>