Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 5.15 692/846] drm/amd/display: Fix the uninitialized variable in enable_stream_features() | Date | Mon, 24 Jan 2022 19:43:29 +0100 |
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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(+)
--- 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));
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