drm/amd/display: Check num_valid_sets before accessing reader_wm_sets[]

From Alex Hung
21f9cb44f8c60bf6c26487d428b1a09ad3e8aebf in linux-6.6.y/6.6.50
b38a4815f79b87efb196cd5121579fc51e29a7fb in mainline linux

diff --git a/sys/dev/pci/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c b/sys/dev/pci/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
index 0c6a4ab..97cdc24 100644 (file)
--- a/sys/dev/pci/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
+++ b/sys/dev/pci/drm/amd/display/dc/clk_mgr/dcn21/rn_clk_mgr.c
@@ -484,7 +484,8 @@ static void build_watermark_ranges(struct clk_bw_params *bw_params, struct pp_sm
                        ranges->reader_wm_sets[num_valid_sets].max_fill_clk_mhz = PP_SMU_WM_SET_RANGE_CLK_UNCONSTRAINED_MAX;
 
                        /* Modify previous watermark range to cover up to max */
-                       ranges->reader_wm_sets[num_valid_sets - 1].max_fill_clk_mhz = PP_SMU_WM_SET_RANGE_CLK_UNCONSTRAINED_MAX;
+                       if (num_valid_sets > 0)
+                               ranges->reader_wm_sets[num_valid_sets - 1].max_fill_clk_mhz = PP_SMU_WM_SET_RANGE_CLK_UNCONSTRAINED_MAX;
                }
                num_valid_sets++;
        }