Messages in this thread | | | From | Prashant Malani <> | Date | Wed, 29 Apr 2020 17:43:24 -0700 | Subject | Re: [PATCH] platform/chrome: cros_ec_typec: Handle NULL EC pointer during probe. |
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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, > > 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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