On Wed, 07 Apr 2021 23:28:48 +0200, Ville Syrjälä wrote: > > On Wed, Apr 07, 2021 at 06:56:15PM +0200, Takashi Iwai wrote: > > On Wed, 07 Apr 2021 18:34:46 +0200, > > Ville Syrjälä wrote: > > > > > > On Fri, Apr 02, 2021 at 10:23:17AM +0200, Takashi Iwai wrote: > > > > intel_dsm_platform_mux_info() tries to parse the ACPI package data > > > > from _DSM for the debug information, but it assumes the fixed format > > > > without checking what values are stored in the elements actually. > > > > When an unexpected value is returned from BIOS, it may lead to GPF or > > > > NULL dereference, as reported recently. > > > > > > > > Add the checks of the contents in the returned values and skip the > > > > values for invalid cases. > > > > > > > > v1->v2: Check the info contents before dereferencing, too > > > > > > > > BugLink: http://bugzilla.opensuse.org/show_bug.cgi?id=1184074 > > > > Cc: <stable@xxxxxxxxxxxxxxx> > > > > Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> > > > > --- > > > > drivers/gpu/drm/i915/display/intel_acpi.c | 22 ++++++++++++++++++++-- > > > > 1 file changed, 20 insertions(+), 2 deletions(-) > > > > > > > > diff --git a/drivers/gpu/drm/i915/display/intel_acpi.c b/drivers/gpu/drm/i915/display/intel_acpi.c > > > > index e21fb14d5e07..833d0c1be4f1 100644 > > > > --- a/drivers/gpu/drm/i915/display/intel_acpi.c > > > > +++ b/drivers/gpu/drm/i915/display/intel_acpi.c > > > > @@ -84,13 +84,31 @@ static void intel_dsm_platform_mux_info(acpi_handle dhandle) > > > > return; > > > > } > > > > > > > > + if (!pkg->package.count) { > > > > + DRM_DEBUG_DRIVER("no connection in _DSM\n"); > > > > + return; > > > > + } > > > > + > > > > connector_count = &pkg->package.elements[0]; > > > > DRM_DEBUG_DRIVER("MUX info connectors: %lld\n", > > > > (unsigned long long)connector_count->integer.value); > > > > for (i = 1; i < pkg->package.count; i++) { > > > > union acpi_object *obj = &pkg->package.elements[i]; > > > > - union acpi_object *connector_id = &obj->package.elements[0]; > > > > - union acpi_object *info = &obj->package.elements[1]; > > > > + union acpi_object *connector_id; > > > > + union acpi_object *info; > > > > + > > > > + if (obj->type != ACPI_TYPE_PACKAGE || obj->package.count < 2) { > > > > + DRM_DEBUG_DRIVER("Invalid object for MUX #%d\n", i); > > > > + continue; > > > > + } > > > > + > > > > + connector_id = &obj->package.elements[0]; > > > > > > You don't want to check connector_id->type as well? > > > > I added only the minimal checks that may lead to Oops. > > OK. I guess misinterpreting something else as an integer isn't > particular dangerous in this case. > > Pushed to drm-intel-next. Thanks. Great, thanks! > Oh, could you ask the bug reporter to attach an acpidump to the > bug? Might be good to have that stuff on record somewhere if/when > someone wants to actually figure out what's going on here. OK, I'll ask. > That said, maybe we should just nuke this whole thing instead? > Unless I'm missing someting this code doesn't seem to actually > do anything... Yeah, that looks nothing but showing the debug information and that can be checked via acpidump output, too... Takashi _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
