[PATCH AUTOSEL 6.11 180/244] drm/amd/display: Check null-initialized variables

Sasha Levin
2024-09-25T11:48:34Z

From: Alex Hung <alex.hung@amd.com>

[ Upstream commit 367cd9ceba1933b63bc1d87d967baf6d9fd241d2 ]

[WHAT & HOW]
drr_timing and subvp_pipe are initialized to null and they are not
always assigned new values. It is necessary to check for null before
dereferencing.

This fixes 2 FORWARD_NULL issues reported by Coverity.

Reviewed-by: Nevenko Stupar <nevenko.stupar@amd.com>
Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Signed-off-by: Jerry Zuo <jerry.zuo@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c b/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
index 9d399c4ce957d..4cb0227bdd270 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
@@ -871,8 +871,9 @@ static bool subvp_drr_schedulable(struct dc *dc, struct dc_state *context)
* for VBLANK: (VACTIVE region of the SubVP pipe can fit the MALL prefetch, VBLANK frame time,
* and the max of (VBLANK blanking time, MALL region)).
*/
- if (stretched_drr_us < (1 / (double)drr_timing->min_refresh_in_uhz) * 1000000 * 1000000 &&
- subvp_active_us - prefetch_us - stretched_drr_us - max_vblank_mallregion > 0)
+ if (drr_timing &&
+ stretched_drr_us < (1 / (double)drr_timing->min_refresh_in_uhz) * 1000000 * 1000000 &&
+ subvp_active_us - prefetch_us - stretched_drr_us - max_vblank_mallregion > 0)
schedulable = true;

return schedulable;
@@ -937,7 +938,7 @@ static bool subvp_vblank_schedulable(struct dc *dc, struct dc_state *context)
if (!subvp_pipe && pipe_mall_type == SUBVP_MAIN)
subvp_pipe = pipe;
}
- if (found) {
+ if (found && subvp_pipe) {
phantom_stream = dc_state_get_paired_subvp_stream(context, subvp_pipe->stream);
main_timing = &subvp_pipe->stream->timing;
phantom_timing = &phantom_stream->timing;
--
2.43.0