Messages in this thread | | | From | Prashant Malani <> | Date | Thu, 30 Apr 2020 09:17:03 -0700 | Subject | Re: [PATCH] platform/chrome: cros_ec_typec: Handle NULL EC pointer during probe. |
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Hi Enric,
On Thu, Apr 30, 2020 at 8:26 AM Enric Balletbo i Serra <enric.balletbo@collabora.com> wrote: > > Hi Prashant, > > On 30/4/20 2:43, Prashant Malani wrote: > > On Wed, Apr 29, 2020 at 5:38 PM Daniil Lunev <dlunev@chromium.org> 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 <dlunev@chromium.org> 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 <enric.balletbo@collabora.com> 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 <dlunev@chromium.org> > >>>>> --- > >>>>> > >>>>> 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); > >>>>>
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