This is a note to let you know that I've just added the patch titled
drm/amd/display: Add null check for set_output_gamma in dcn30_set_output_transfer_func
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-amd-display-add-null-check-for-set_output_gamma-.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit fbdecfbfa4166516d3df0fbb6de2323a7d64e42b
Author: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
Date: Mon Jul 22 17:18:17 2024 +0530
drm/amd/display: Add null check for set_output_gamma in dcn30_set_output_transfer_func
[ Upstream commit 08ae395ea22fb3d9b318c8bde28c0dfd2f5fa4d2 ]
This commit adds a null check for the set_output_gamma function pointer
in the dcn30_set_output_transfer_func function. Previously,
set_output_gamma was being checked for nullity at line 386, but then it
was being dereferenced without any nullity check at line 401. This
could potentially lead to a null pointer dereference error if
set_output_gamma is indeed null.
To fix this, we now ensure that set_output_gamma is not null before
dereferencing it. We do this by adding a nullity check for
set_output_gamma before the call to set_output_gamma at line 401. If
set_output_gamma is null, we log an error message and do not call the
function.
This fix prevents a potential null pointer dereference error.
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c:401 dcn30_set_output_transfer_func()
error: we previously assumed 'mpc->funcs->set_output_gamma' could be null (see line 386)
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn30/dcn30_hwseq.c
373 bool dcn30_set_output_transfer_func(struct dc *dc,
374 struct pipe_ctx *pipe_ctx,
375 const struct dc_stream_state *stream)
376 {
377 int mpcc_id = pipe_ctx->plane_res.hubp->inst;
378 struct mpc *mpc = pipe_ctx->stream_res.opp->ctx->dc->res_pool->mpc;
379 const struct pwl_params *params = NULL;
380 bool ret = false;
381
382 /* program OGAM or 3DLUT only for the top pipe*/
383 if (pipe_ctx->top_pipe == NULL) {
384 /*program rmu shaper and 3dlut in MPC*/
385 ret = dcn30_set_mpc_shaper_3dlut(pipe_ctx, stream);
386 if (ret == false && mpc->funcs->set_output_gamma) {
^^^^^^^^^^^^^^^^^^^^^^^^^^^^ If this is NULL
387 if (stream->out_transfer_func.type == TF_TYPE_HWPWL)
388 params = &stream->out_transfer_func.pwl;
389 else if (pipe_ctx->stream->out_transfer_func.type ==
390 TF_TYPE_DISTRIBUTED_POINTS &&
391 cm3_helper_translate_curve_to_hw_format(
392 &stream->out_transfer_func,
393 &mpc->blender_params, false))
394 params = &mpc->blender_params;
395 /* there are no ROM LUTs in OUTGAM */
396 if (stream->out_transfer_func.type == TF_TYPE_PREDEFINED)
397 BREAK_TO_DEBUGGER();
398 }
399 }
400
--> 401 mpc->funcs->set_output_gamma(mpc, mpcc_id, params);
^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Then it will crash
402 return ret;
403 }
Fixes: d99f13878d6f ("drm/amd/display: Add DCN3 HWSEQ")
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Cc: Tom Chung <chiahsuan.chung@xxxxxxx>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
Cc: Roman Li <roman.li@xxxxxxx>
Cc: Hersen Wu <hersenxs.wu@xxxxxxx>
Cc: Alex Hung <alex.hung@xxxxxxx>
Cc: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
Cc: Harry Wentland <harry.wentland@xxxxxxx>
Cc: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
Reviewed-by: Tom Chung <chiahsuan.chung@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c
index ba47a1c8eec10..d59af329d0009 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn30/dcn30_hwseq.c
@@ -214,7 +214,11 @@ bool dcn30_set_output_transfer_func(struct dc *dc,
}
}
- mpc->funcs->set_output_gamma(mpc, mpcc_id, params);
+ if (mpc->funcs->set_output_gamma)
+ mpc->funcs->set_output_gamma(mpc, mpcc_id, params);
+ else
+ DC_LOG_ERROR("%s: set_output_gamma function pointer is NULL.\n", __func__);
+
return ret;
}
