"value":"In the Linux kernel, the following vulnerability has been resolved:\n\ndrm/amd/display: Add null check for set_output_gamma in dcn30_set_output_transfer_func\n\nThis commit adds a null check for the set_output_gamma function pointer\nin the dcn30_set_output_transfer_func function. Previously,\nset_output_gamma was being checked for nullity at line 386, but then it\nwas being dereferenced without any nullity check at line 401. This\ncould potentially lead to a null pointer dereference error if\nset_output_gamma is indeed null.\n\nTo fix this, we now ensure that set_output_gamma is not null before\ndereferencing it. We do this by adding a nullity check for\nset_output_gamma before the call to set_output_gamma at line 401. If\nset_output_gamma is null, we log an error message and do not call the\nfunction.\n\nThis fix prevents a potential null pointer dereference error.\n\ndrivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c:401 dcn30_set_output_transfer_func()\nerror: we previously assumed 'mpc->funcs->set_output_gamma' could be null (see line 386)\n\ndrivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c\n 373 bool dcn30_set_output_transfer_func(struct dc *dc,\n 374 struct pipe_ctx *pipe_ctx,\n 375 const struct dc_stream_state *stream)\n 376 {\n 377 int mpcc_id = pipe_ctx->plane_res.hubp->inst;\n 378 struct mpc *mpc = pipe_ctx->stream_res.opp->ctx->dc->res_pool->mpc;\n 379 const struct pwl_params *params = NULL;\n 380 bool ret = false;\n 381\n 382 /* program OGAM or 3DLUT only for the top pipe*/\n 383 if (pipe_ctx->top_pipe == NULL) {\n 384 /*program rmu shaper and 3dlut in MPC*/\n 385 ret = dcn30_set_mpc_shaper_3dlut(pipe_ctx, stream);\n 386 if (ret == false && mpc->funcs->set_output_gamma) {\n ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ If this is NULL\n\n 387 if (stream->out_transfer_func.type == TF_TYPE_HWPWL)\n 388 params = &stream->out_transfer_func.pwl;\n 389 else if (pipe_ctx->stream->out_transfer_func.type ==\n 390 TF_TYPE_DISTRIBUTED_POINTS &&\n 391 cm3_helper_translate_curve_to_hw_format(\n 392 &stream->out_transfer_func,\n 393 &mpc->blender_params, false))\n 394 params = &mpc->blender_params;\n 395 /* there are no ROM LUTs in OUTGAM */\n 396 if (stream->out_transfer_func.type == TF_TYPE_PREDEFINED)\n 397 BREAK_TO_DEBUGGER();\n 398 }\n 399 }\n 400\n--> 401 mpc->funcs->set_output_gamma(mpc, mpcc_id, params);\n ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Then it will crash\n\n 402 return ret;\n 403 }"
