From: Srinivasan Shanmugam srinivasan.shanmugam@amd.com

[ Upstream commit ac2140449184a26eac99585b7f69814bd3ba8f2d ]

This commit addresses a potential null pointer dereference issue in the `dcn32_acquire_idle_pipe_for_head_pipe_in_layer` function. The issue could occur when `head_pipe` is null.

The fix adds a check to ensure `head_pipe` is not null before asserting it. If `head_pipe` is null, the function returns NULL to prevent a potential null pointer dereference.

Reported by smatch: drivers/gpu/drm/amd/amdgpu/../display/dc/resource/dcn32/dcn32_resource.c:2690 dcn32_acquire_idle_pipe_for_head_pipe_in_layer() error: we previously assumed 'head_pipe' could be null (see line 2681)

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: Frank.C tom.and.jerry.official.mail@gmail.com --- drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c index ef47fb2f6905..2b5bd3aa3229 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c +++ b/drivers/gpu/drm/amd/display/dc/dcn32/dcn32_resource.c @@ -2558,8 +2558,10 @@ struct pipe_ctx *dcn32_acquire_idle_pipe_for_head_pipe_in_layer( struct resource_context *old_ctx = &stream->ctx->dc->current_state->res_ctx; int head_index;

- if (!head_pipe) + if (!head_pipe) { ASSERT(0); + return NULL; + }

/* * Modified from dcn20_acquire_idle_pipe_for_layer