From: Srinivasan Shanmugam <srinivasan.shanmu...@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.ch...@amd.com>
Cc: Rodrigo Siqueira <rodrigo.sique...@amd.com>
Cc: Roman Li <roman...@amd.com>
Cc: Alex Hung <alex.h...@amd.com>
Cc: Aurabindo Pillai <aurabindo.pil...@amd.com>
Cc: Harry Wentland <harry.wentl...@amd.com>
Cc: Hamza Mahfooz <hamza.mahf...@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmu...@amd.com>
Reviewed-by: Tom Chung <chiahsuan.ch...@amd.com>
Signed-off-by: Alex Deucher <alexander.deuc...@amd.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 .../amd/display/dc/hwss/dcn20/dcn20_hwseq.c   | 30 ++++++++++++-------
 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c 
b/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c
index 456e19e0d415c..17d1c195663a0 100644
--- a/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dcn20/dcn20_hwseq.c
@@ -1921,22 +1921,29 @@ static void dcn20_program_pipe(
                                dc->res_pool->hubbub, 
pipe_ctx->plane_res.hubp->inst, pipe_ctx->hubp_regs.det_size);
        }
 
-       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 (hws->funcs.populate_mcm_luts) {
-               hws->funcs.populate_mcm_luts(dc, pipe_ctx, 
pipe_ctx->plane_state->mcm_luts,
-                               pipe_ctx->plane_state->lut_bank_a);
-               pipe_ctx->plane_state->lut_bank_a = 
!pipe_ctx->plane_state->lut_bank_a;
+               if (pipe_ctx->plane_state) {
+                       hws->funcs.populate_mcm_luts(dc, pipe_ctx, 
pipe_ctx->plane_state->mcm_luts,
+                                                    
pipe_ctx->plane_state->lut_bank_a);
+                       pipe_ctx->plane_state->lut_bank_a = 
!pipe_ctx->plane_state->lut_bank_a;
+               }
        }
        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
@@ -1946,7 +1953,8 @@ 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
@@ -1970,7 +1978,7 @@ 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

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