[PATCH AUTOSEL 6.11 142/244] drm/amd/display: Add null check for pipe_ctx->plane_state in dcn20_program_pipe

Sasha Levin
2024-09-25T11:45:34Z

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>
---
.../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