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[23.128.96.18]) by mx.google.com with ESMTP id ck10si1789681ejb.431.2020.05.05.13.41.01; Tue, 05 May 2020 13:41:26 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=collabora.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729011AbgEEUgs (ORCPT + 99 others); Tue, 5 May 2020 16:36:48 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:45884 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726593AbgEEUgs (ORCPT ); Tue, 5 May 2020 16:36:48 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: eballetbo) with ESMTPSA id DE4D62A1A91 Subject: Re: [PATCH] platform/chrome: cros_ec_typec: Handle NULL EC pointer during probe. To: Daniil Lunev , Prashant Malani Cc: LKML , Benson Leung , Guenter Roeck References: <20200428110253.1.I926f6741079cafb04ecb592130aef75b24ad31ae@changeid> <20200501005609.GA131713@google.com> From: Enric Balletbo i Serra Message-ID: Date: Tue, 5 May 2020 22:36:37 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi. On 1/5/20 5:22, Daniil Lunev wrote: > 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. I'd prefer to not push the patch. If at some point this is starts of being possible we will catch soon. Thank you, Enric > Cheers, > Daniil > > On Fri, May 1, 2020 at 10:56 AM Prashant Malani wrote: >> >> 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 = 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: error -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 wrote: >>>> >>>> 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 hierarchy 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 erroneous >>>>>> ACPI device entry. >>>>>> >>>>> >>>>> Thanks for the clarification. Then, I don't think we need to upstream this. This >>>>> kind of "defensive-programming" it's not something that should matter 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 to >>>> 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 returned to the >>>>>>>>>> probe function which leads to NULL pointer dereference when trying 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 situation >>>>>>>>> >>>>>>>>> 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 condition 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/drivers/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 platform_device *pdev) >>>>>>>>>> >>>>>>>>>> typec->dev = dev; >>>>>>>>>> typec->ec = 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 = cros_typec_get_cmd_version(typec); >>>>>>>>>>