From bf4e4b97d0fdc66f04fc19d807e24dd8421b8f11 Mon Sep 17 00:00:00 2001 From: Srinivasan Shanmugam Date: Wed, 13 Aug 2025 12:14:01 +0530 Subject: [PATCH] drm/amd/display: Add NULL pointer checks in dc_stream cursor attribute functions The function dc_stream_set_cursor_attributes() currently dereferences the `stream` pointer and nested members `stream->ctx->dc->current_state` without checking for NULL. All callers of these functions, such as in `dcn30_apply_idle_power_optimizations()` and `amdgpu_dm_plane_handle_cursor_update()`, already perform NULL checks before calling these functions. Fixes below: drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:336 dc_stream_program_cursor_attributes() error: we previously assumed 'stream' could be null (see line 334) drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c 327 bool dc_stream_program_cursor_attributes( 328 struct dc_stream_state *stream, 329 const struct dc_cursor_attributes *attributes) 330 { 331 struct dc *dc; 332 bool reset_idle_optimizations = false; 333 334 dc = stream ? stream->ctx->dc : NULL; ^^^^^^ The old code assumed stream could be NULL. 335 --> 336 if (dc_stream_set_cursor_attributes(stream, attributes)) { ^^^^^^ The refactor added an unchecked dereference. drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c 313 bool dc_stream_set_cursor_attributes( 314 struct dc_stream_state *stream, 315 const struct dc_cursor_attributes *attributes) 316 { 317 bool result = false; 318 319 if (dc_stream_check_cursor_attributes(stream, stream->ctx->dc->current_state, attributes)) { ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Here. This function used to check for if stream as NULL and return false at the start. Probably we should add that back. Fixes: 4465dd0e41e8 ("drm/amd/display: Refactor SubVP cursor limiting logic") Reported-by: Dan Carpenter Cc: Alex Hung Cc: Alvin Lee Cc: Ray Wu Cc: Dillon Varone Cc: Aurabindo Pillai Cc: Roman Li Cc: ChiaHsuan Chung Cc: Harry Wentland Cc: Daniel Wheeler Cc: Tom Chung Cc: Wenjing Liu Cc: Jun Lei Signed-off-by: Srinivasan Shanmugam Reviewed-by: Dillon Varone Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/display/dc/core/dc_stream.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c index 4d6bc9fd4faa8..9ac2d41f8fcae 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_stream.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_stream.c @@ -316,6 +316,9 @@ bool dc_stream_set_cursor_attributes( { bool result = false; + if (!stream) + return false; + if (dc_stream_check_cursor_attributes(stream, stream->ctx->dc->current_state, attributes)) { stream->cursor_attributes = *attributes; result = true; @@ -331,7 +334,10 @@ bool dc_stream_program_cursor_attributes( struct dc *dc; bool reset_idle_optimizations = false; - dc = stream ? stream->ctx->dc : NULL; + if (!stream) + return false; + + dc = stream->ctx->dc; if (dc_stream_set_cursor_attributes(stream, attributes)) { dc_z10_restore(dc); -- 2.47.3