From: Yizhuo Zhai <yzhai003@xxxxxxx>
commit 0726ed3065eeb910f9cea0c933bc021a848e00b3 upstream.
In function enable_stream_features(), the variable "old_downspread.raw"
could be uninitialized if core_link_read_dpcd() fails, however, it is
used in the later if statement, and further, core_link_write_dpcd()
may write random value, which is potentially unsafe.
Fixes: 6016cd9dba0f ("drm/amd/display: add helper for enabling mst stream features")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Yizhuo Zhai <yzhai003@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/display/dc/core/dc_link.c | 2 ++
1 file changed, 2 insertions(+)
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -1696,6 +1696,8 @@ static void enable_stream_features(struc
union down_spread_ctrl old_downspread;
union down_spread_ctrl new_downspread;
+ memset(&old_downspread, 0, sizeof(old_downspread));
+
core_link_read_dpcd(link, DP_DOWNSPREAD_CTRL,
&old_downspread.raw, sizeof(old_downspread));
