From: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Date: Wed, 10 Jan 2024 15:28:35 +0000 (+0530)
Subject: drm/amd/display: Fix late derefrence 'dsc' check in 'link_set_dsc_pps_packet()'
X-Git-Tag: v6.6.17~514
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6aa5ede6665122f4c8abce3c6eba06b49e54d25c;p=platform%2Fkernel%2Flinux-starfive.git

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

commit 3bb9b1f958c3d986ed90a3ff009f1e77e9553207 upstream.

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@vger.kernel.org
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Hamza Mahfooz <hamza.mahfooz@amd.com>
Cc: Wenjing Liu <wenjing.liu@amd.com>
Cc: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

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 35d087c..a96f074 100644
--- a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
@@ -873,11 +873,15 @@ 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];