drm/display: fix possible null-pointer dereference in dcn10_set_clock()

From Tuo Li
83449db3aac0895147eac723bf23d0739720b968 in linux 5.10.y/5.10.67
554594567b1fa3da74f88ec7b2dc83d000c58e98 in mainline linux

diff --git a/sys/dev/pci/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c b/sys/dev/pci/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
index 0d1e7b5..532f6a1 100644 (file)
--- a/sys/dev/pci/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
+++ b/sys/dev/pci/drm/amd/display/dc/dcn10/dcn10_hw_sequencer.c
@@ -3740,13 +3740,12 @@ enum dc_status dcn10_set_clock(struct dc *dc,
        struct dc_clock_config clock_cfg = {0};
        struct dc_clocks *current_clocks = &context->bw_ctx.bw.dcn.clk;
 
-       if (dc->clk_mgr && dc->clk_mgr->funcs->get_clock)
-                               dc->clk_mgr->funcs->get_clock(dc->clk_mgr,
-                                               context, clock_type, &clock_cfg);
-
-       if (!dc->clk_mgr->funcs->get_clock)
+       if (!dc->clk_mgr || !dc->clk_mgr->funcs->get_clock)
                return DC_FAIL_UNSUPPORTED_1;
 
+       dc->clk_mgr->funcs->get_clock(dc->clk_mgr,
+               context, clock_type, &clock_cfg);
+
        if (clk_khz > clock_cfg.max_clock_khz)
                return DC_FAIL_CLK_EXCEED_MAX;
 
@@ -3764,7 +3763,7 @@ enum dc_status dcn10_set_clock(struct dc *dc,
        else
                return DC_ERROR_UNEXPECTED;
 
-       if (dc->clk_mgr && dc->clk_mgr->funcs->update_clocks)
+       if (dc->clk_mgr->funcs->update_clocks)
                                dc->clk_mgr->funcs->update_clocks(dc->clk_mgr,
                                context, true);
        return DC_OK;