[PATCH 5.4 098/183] drm/amd/display: Fix potential NULL pointer dereferences in 'dcn10_set_output_transfer_func()'

[Sasha Levin]

From: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>

[ Upstream commit 9ccfe80d022df7c595f1925afb31de2232900656 ]

The 'stream' pointer is used in dcn10_set_output_transfer_func() before
the check if 'stream' is NULL.

Fixes the below:
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn10/dcn10_hwseq.c:1892 dcn10_set_output_transfer_func() warn: variable dereferenced before check 'stream' (see line 1875)

Fixes: ddef02de0d71 ("drm/amd/display: add null checks before logging")
Cc: Wyatt Wood <wyatt.wood@xxxxxxx>
Cc: Anthony Koo <Anthony.Koo@xxxxxxx>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
Cc: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
Reviewed-by: Anthony Koo <Anthony.Koo@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index c4c99bc7f2890..3059739695d8c 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -1470,6 +1470,9 @@ dcn10_set_output_transfer_func(struct pipe_ctx *pipe_ctx,
 {
 	struct dpp *dpp = pipe_ctx->plane_res.dpp;
 
+	if (!stream)
+		return false;
+
 	if (dpp == NULL)
 		return false;
 
@@ -1492,8 +1495,8 @@ dcn10_set_output_transfer_func(struct pipe_ctx *pipe_ctx,
 	} else
 		dpp->funcs->dpp_program_regamma_pwl(dpp, NULL, OPP_REGAMMA_BYPASS);
 
-	if (stream != NULL && stream->ctx != NULL &&
-			stream->out_transfer_func != NULL) {
+	if (stream->ctx &&
+	    stream->out_transfer_func) {
 		log_tf(stream->ctx,
 				stream->out_transfer_func,
 				dpp->regamma_params.hw_points_num);
-- 
2.43.0