From 3bf997ec299cdf7280b2039806e5e1d847df111a Mon Sep 17 00:00:00 2001 From: Yizhuo Zhai Date: Fri, 17 Dec 2021 20:22:23 -0800 Subject: [PATCH] drm/amd/display: Fix the uninitialized variable in enable_stream_features() 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 Signed-off-by: Alex Deucher Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/amd/display/dc/core/dc_link.c | 2 ++ 1 file changed, 2 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 1e44b13c1c7de..3c4205248efc2 100644 --- 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(struct pipe_ctx *pipe_ctx) 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));