Messages in this thread | | | Subject | Re: [PATCH] HID: intel-ish-hid: Fix kernel panic during warm reset | From | srinivas pandruvada <> | Date | Mon, 27 Mar 2023 05:10:14 -0700 |
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On Sun, 2023-03-26 at 20:23 -0700, Tanu Malhotra wrote:
some minor nits below.
> During warm reset device->fw_client is set to NULL. If a bus driver > is > registered after this NULL setting and before new firmware clients > are > enumerated by ISHTP, kernel panic will result in the function > ishtp_cl_bus_match(). This is because of reference to > device->fw_client->props.protocol_name. > > ISH firmware after getting successfully loaded, sends a warm reset > notification to remove all clients from the bus and sets > device->fw_client to NULL. Until kernel v5.15, all enabled ISHTP > kernel > module drivers were loaded after any of the first ISHTP device was > registered, regardless of whether it was a matched or an unmatched > device. This resulted in all drivers getting registered much before > the > warm reset notification from ISH. Starting kernel v5.16, this issue > got > exposed after the change was introduced to load only bus drivers for > the > respective matching devices. One paragraph break will be better.
> In this scenario, cros_ec_ishtp device and > cros_ec_ishtp driver are registered after the warm reset > device_fw_client NULL setting. cros_ec_ishtp driver_register() > triggers > the callback to ishtp_cl_bus_match() to match driver to the device > and > causes kernel panic in guid_equal() when dereferencing fw_client NULL > pointer to get protocol_name. > > Fixes: f155dfeaa4ee ("platform/x86: isthp_eclite: only load for > matching devices") > Fixes: facfe0a4fdce ("platform/chrome: chros_ec_ishtp: only load for > matching devices") > Fixes: 0d0cccc0fd83 ("HID: intel-ish-hid: hid-client: only load for > matching devices") > Fixes: 44e2a58cb880 ("HID: intel-ish-hid: fw-loader: only load for > matching devices") > No need of blank line.
> Signed-off-by: Tanu Malhotra <tanu.malhotra@intel.com> > Tested-by: Shaunak Saha <shaunak.saha@intel.com> You can also add Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Also add Cc: <stable@vger.kernel.org> # 5.16+
> --- When you submit "PATCH v2", Add change log here. (That is below "---"). Something like this: v2 - Updated commit description - Added CC to stable
> drivers/hid/intel-ish-hid/ishtp/bus.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/hid/intel-ish-hid/ishtp/bus.c > b/drivers/hid/intel-ish-hid/ishtp/bus.c > index 81385ab37fa9..4f540906268f 100644 > --- a/drivers/hid/intel-ish-hid/ishtp/bus.c > +++ b/drivers/hid/intel-ish-hid/ishtp/bus.c > @@ -241,8 +241,8 @@ static int ishtp_cl_bus_match(struct device *dev, > struct device_driver *drv) > struct ishtp_cl_device *device = to_ishtp_cl_device(dev); > struct ishtp_cl_driver *driver = to_ishtp_cl_driver(drv); > > - return guid_equal(&driver->id[0].guid, > - &device->fw_client->props.protocol_name); > + return(device->fw_client ? guid_equal(&driver->id[0].guid, > + &device->fw_client- > >props.protocol_name) : 0); Align the second line to char "d" after "(".
Thanks, Srinivas
> } > > /**
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