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 f8e01ca09d964697a0ec6e19abdbd62c97f3a985..04d1ecd6e5934efef83f78efa60747f2af33112e 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
+++ b/drivers/gpu/drm/amd/display/dc/link/link_dpms.c
@@ -875,11 +875,15 @@ 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];