[PATCH 6.6.y] drm/amd/display: Add null check for pipe_ctx->plane_state in dcn20_program_pipe - Linux-stable-mirror

26 Nov 2024

From: Srinivasan Shanmugam srinivasan.shanmugam@amd.com
[ Upstream commit 8e4ed3cf1642df0c4456443d865cff61a9598aa8 ]
This commit addresses a null pointer dereference issue in the
`dcn20_program_pipe` function. The issue could occur when
`pipe_ctx->plane_state` is null.
The fix adds a check to ensure `pipe_ctx->plane_state` is not null
before accessing. This prevents a null pointer dereference.
Reported by smatch:
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn20/dcn20_hwseq.c:1925 dcn20_program_pipe() error: we previously assumed 'pipe_ctx->plane_state' could be null (see line 1877)
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: Sasha Levin sashal@kernel.org
[Xiangyu: BP to fix CVE: CVE-2024-49914, modified the file path from
drivers/gpu/drm/amd/amdgpu/../display/dc/hwss/dcn20/dcn20_hwseq.c to
drivers/gpu/drm/amd/amdgpu/../display/dc/dcn20/dcn20_hwseq.c
and minor conflict resolution]
Signed-off-by: Xiangyu Chen xiangyu.chen@windriver.com
---
 .../drm/amd/display/dc/dcn20/dcn20_hwseq.c    | 22 ++++++++++++-------
 1 file changed, 14 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
index 12af2859002f..cd1d1b7283ab 100644
--- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c
@@ -1732,17 +1732,22 @@ static void dcn20_program_pipe(
    	dc->res_pool->hubbub->funcs->program_det_size(
    		dc->res_pool->hubbub, pipe_ctx->plane_res.hubp->inst, pipe_ctx->det_buffer_size_kb);
-	if (pipe_ctx->update_flags.raw || pipe_ctx->plane_state->update_flags.raw || pipe_ctx->stream->update_flags.raw)
+	if (pipe_ctx->update_flags.raw ||
+	    (pipe_ctx->plane_state && pipe_ctx->plane_state->update_flags.raw) ||
+	    pipe_ctx->stream->update_flags.raw)
    	dcn20_update_dchubp_dpp(dc, pipe_ctx, context);
-	if (pipe_ctx->update_flags.bits.enable
-			|| pipe_ctx->plane_state->update_flags.bits.hdr_mult)
+	if (pipe_ctx->update_flags.bits.enable ||
+	    (pipe_ctx->plane_state && pipe_ctx->plane_state->update_flags.bits.hdr_mult))
    	hws->funcs.set_hdr_multiplier(pipe_ctx);
if (pipe_ctx->update_flags.bits.enable ||
-	    pipe_ctx->plane_state->update_flags.bits.in_transfer_func_change ||
-	    pipe_ctx->plane_state->update_flags.bits.gamma_change ||
-	    pipe_ctx->plane_state->update_flags.bits.lut_3d)
+	    (pipe_ctx->plane_state &&
+	     pipe_ctx->plane_state->update_flags.bits.in_transfer_func_change) ||
+	    (pipe_ctx->plane_state &&
+	     pipe_ctx->plane_state->update_flags.bits.gamma_change) ||
+	    (pipe_ctx->plane_state &&
+	     pipe_ctx->plane_state->update_flags.bits.lut_3d))
    	hws->funcs.set_input_transfer_func(dc, pipe_ctx, pipe_ctx->plane_state);
/* dcn10_translate_regamma_to_hw_format takes 750us to finish
@@ -1752,7 +1757,8 @@ static void dcn20_program_pipe(
    if (pipe_ctx->update_flags.bits.enable ||
    		pipe_ctx->update_flags.bits.plane_changed ||
    		pipe_ctx->stream->update_flags.bits.out_tf ||
-			pipe_ctx->plane_state->update_flags.bits.output_tf_change)
+			(pipe_ctx->plane_state &&
+			 pipe_ctx->plane_state->update_flags.bits.output_tf_change))
    	hws->funcs.set_output_transfer_func(dc, pipe_ctx, pipe_ctx->stream);
/* If the pipe has been enabled or has a different opp, we
@@ -1776,7 +1782,7 @@ static void dcn20_program_pipe(
    }
/* Set ABM pipe after other pipe configurations done */
-	if (pipe_ctx->plane_state->visible) {
+	if ((pipe_ctx->plane_state && pipe_ctx->plane_state->visible)) {
    	if (pipe_ctx->stream_res.abm) {
    		dc->hwss.set_pipe(pipe_ctx);
    		pipe_ctx->stream_res.abm->funcs->set_abm_level(pipe_ctx->stream_res.abm,
-- 
2.43.0



    