[PATCH] drm/amd/display: Fix late derefrence 'dsc' check in 'link_set_dsc_pps_packet()'

From: Srinivasan Shanmugam
Date: Wed Jan 10 2024 - 10:28:35 EST


In link_set_dsc_pps_packet(), 'struct display_stream_compressor *dsc'
was dereferenced in a DC_LOGGER_INIT(dsc->ctx->logger); before the 'dsc'
NULL pointer check.

Fixes the below:
drivers/gpu/drm/amd/amdgpu/../display/dc/link/link_dpms.c:905 link_set_dsc_pps_packet() warn: variable dereferenced before check 'dsc' (see line 903)

Cc: stable@xxxxxxxxxxxxxxx
Cc: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@xxxxxxx>
Cc: Hamza Mahfooz <hamza.mahfooz@xxxxxxx>
Cc: Wenjing Liu <wenjing.liu@xxxxxxx>
Cc: Qingqing Zhuo <qingqing.zhuo@xxxxxxx>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@xxxxxxx>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@xxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
---
drivers/gpu/drm/amd/display/dc/link/link_dpms.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
index 3de148004c066..3cbfbf8d107e9 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
@@ -900,11 +900,15 @@ bool link_set_dsc_pps_packet(struct pipe_ctx *pipe_ctx, bool enable, bool immedi
{
struct display_stream_compressor *dsc = pipe_ctx->stream_res.dsc;
struct dc_stream_state *stream = pipe_ctx->stream;
- DC_LOGGER_INIT(dsc->ctx->logger);

- if (!pipe_ctx->stream->timing.flags.DSC || !dsc)
+ if (!pipe_ctx->stream->timing.flags.DSC)
return false;

+ if (!dsc)
+ return false;
+
+ DC_LOGGER_INIT(dsc->ctx->logger);
+
if (enable) {
struct dsc_config dsc_cfg;
uint8_t dsc_packed_pps[128];
--
2.43.0