diff mbox series

[5.16,0861/1039] drm/amd/display: Fix the uninitialized variable in enable_stream_features()

Message ID 20220124184154.238652206@linuxfoundation.org
State New
Headers show
Series None | expand

Commit Message

Greg Kroah-Hartman Jan. 24, 2022, 6:44 p.m. UTC 
From: Yizhuo Zhai <yzhai003@ucr.edu>

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@vger.kernel.org
Signed-off-by: Yizhuo Zhai <yzhai003@ucr.edu>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link.c |    2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
@@ -1844,6 +1844,8 @@  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));