From a986f9345467b8d39f0aff39d80207e4e91aae0c Mon Sep 17 00:00:00 2001 From: Nicholas Kazlauskas Date: Fri, 18 Dec 2020 12:14:00 -0500 Subject: [PATCH] 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 Signed-off-by: Nicholas Kazlauskas Reviewed-by: Eric Yang Acked-by: Anson Jacob Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/dc/core/dc_link.c | 5 +++++ 1 file changed, 5 insertions(+) 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 e1e5d81a5e438..21c7b642a8b4e 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -1454,6 +1454,11 @@ static bool dc_link_construct(struct dc_link *link, 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));