[PATCH AUTOSEL 6.11 152/244] drm/amd/display: Add NULL check for function pointer in dcn20_set_output_transfer_func

Sasha Levin
2024-09-25T11:46:28Z

From: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>

[ Upstream commit 62ed6f0f198da04e884062264df308277628004f ]

This commit adds a null check for the set_output_gamma function pointer
in the dcn20_set_output_transfer_func function. Previously,
set_output_gamma was being checked for null at line 1030, but then it
was being dereferenced without any null check at line 1048. This could
potentially lead to a null pointer dereference error if set_output_gamma
is null.

To fix this, we now ensure that set_output_gamma is not null before
dereferencing it. We do this by adding a null check for set_output_gamma
before the call to set_output_gamma at line 1048.

Cc: Tom Chung <chiahsuan.chung@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Roman Li <roman.li@amd.com>
Cc: Alex Hung <alex.hung@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Tom Chung <chiahsuan.chung@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/hwss/dcn20/dcn20_hwseq.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c
index 17d1c195663a0..7ca0da88290af 100644
--- a/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c
@@ -1044,7 +1044,8 @@ bool dcn20_set_output_transfer_func(struct dc *dc, struct pipe_ctx *pipe_ctx,
/*
* if above if is not executed then 'params' equal to 0 and set in bypass
*/
- mpc->funcs->set_output_gamma(mpc, mpcc_id, params);
+ if (mpc->funcs->set_output_gamma)
+ mpc->funcs->set_output_gamma(mpc, mpcc_id, params);

return true;
}
--
2.43.0