Patch "drm/amd/display: Check null-initialized variables" has been added to the 6.6-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    drm/amd/display: Check null-initialized variables

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-check-null-initialized-variables.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 1e6ebb31c85093a8b72d88020bf008502747e5c0
Author: Alex Hung <alex.hung@xxxxxxx>
Date:   Tue Nov 26 19:23:26 2024 +0800

    drm/amd/display: Check null-initialized variables
    
    [ Upstream commit 367cd9ceba1933b63bc1d87d967baf6d9fd241d2 ]
    
    [WHAT & HOW]
    drr_timing and subvp_pipe are initialized to null and they are not
    always assigned new values. It is necessary to check for null before
    dereferencing.
    
    This fixes 2 FORWARD_NULL issues reported by Coverity.
    
    Reviewed-by: Nevenko Stupar <nevenko.stupar@xxxxxxx>
    Reviewed-by: Rodrigo Siqueira <rodrigo.siqueira@xxxxxxx>
    Signed-off-by: Jerry Zuo <jerry.zuo@xxxxxxx>
    Signed-off-by: Alex Hung <alex.hung@xxxxxxx>
    Tested-by: Daniel Wheeler <daniel.wheeler@xxxxxxx>
    Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
    Signed-off-by: Xiangyu Chen <xiangyu.chen@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c b/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
index 3d82cbef12740..ac6357c089e70 100644
--- a/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
+++ b/drivers/gpu/drm/amd/display/dc/dml/dcn32/dcn32_fpu.c
@@ -932,8 +932,9 @@ static bool subvp_drr_schedulable(struct dc *dc, struct dc_state *context)
 	 * for VBLANK: (VACTIVE region of the SubVP pipe can fit the MALL prefetch, VBLANK frame time,
 	 * and the max of (VBLANK blanking time, MALL region)).
 	 */
-	if (stretched_drr_us < (1 / (double)drr_timing->min_refresh_in_uhz) * 1000000 * 1000000 &&
-			subvp_active_us - prefetch_us - stretched_drr_us - max_vblank_mallregion > 0)
+	if (drr_timing &&
+	    stretched_drr_us < (1 / (double)drr_timing->min_refresh_in_uhz) * 1000000 * 1000000 &&
+	    subvp_active_us - prefetch_us - stretched_drr_us - max_vblank_mallregion > 0)
 		schedulable = true;
 
 	return schedulable;
@@ -995,7 +996,7 @@ static bool subvp_vblank_schedulable(struct dc *dc, struct dc_state *context)
 		if (!subvp_pipe && pipe->stream->mall_stream_config.type == SUBVP_MAIN)
 			subvp_pipe = pipe;
 	}
-	if (found) {
+	if (found && subvp_pipe) {
 		main_timing = &subvp_pipe->stream->timing;
 		phantom_timing = &subvp_pipe->stream->mall_stream_config.paired_stream->timing;
 		vblank_timing = &context->res_ctx.pipe_ctx[vblank_index].stream->timing;