This is a note to let you know that I've just added the patch titled
drm/amd/display: Guard against NULL pointer deref when get_i2c_info fails
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amd-display-guard-against-null-pointer-deref-whe.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit e0ddc22b561dcf20c0a78e3a1c4a67d0d47c29ec
Author: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
Date: Fri Dec 18 12:14:00 2020 -0500
drm/amd/display: Guard against NULL pointer deref when get_i2c_info fails
[ Upstream commit 44a09e3d95bd2b7b0c224100f78f335859c4e193 ]
[Why]
If the BIOS table is invalid or corrupt then get_i2c_info can fail
and we dereference a NULL pointer.
[How]
Check that ddc_pin is not NULL before using it and log an error if it
is because this is unexpected.
Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@xxxxxxx>
Reviewed-by: Eric Yang <eric.yang2@xxxxxxx>
Acked-by: Anson Jacob <anson.jacob@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
index fa0e6c8e2447..e3bedf4cc9c0 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -1124,6 +1124,11 @@ static bool construct(
goto ddc_create_fail;
}
+ if (!link->ddc->ddc_pin) {
+ DC_ERROR("Failed to get I2C info for connector!\n");
+ goto ddc_create_fail;
+ }
+
link->ddc_hw_inst =
dal_ddc_get_line(
dal_ddc_service_get_ddc_pin(link->ddc));
