... and somethings not right.  debugger KBUILD_SYM shows it:

these records are same as those shown in early boot output pasted previously

these records look right

(gdb) p *__start___dyndbg_sites@10
$2 = {{modname = 0xffffffff825a8ab9 "head64",
    filename = 0xffffffff825a8ac0 "include/linux/dynamic_debug.h",
    function = 0xffffffff825a8ab9 "head64"}, {modname = 0xffffffff825a8ade "ebda",
    filename = 0xffffffff825a8ac0 "include/linux/dynamic_debug.h", function = 0xffffffff825a8ade "ebda"}, {
    modname = 0xffffffff825a8ae3 "platform_quirks",
    filename = 0xffffffff825a8ac0 "include/linux/dynamic_debug.h",
    function = 0xffffffff825a8ae3 "platform_quirks"}, {modname = 0xffffffff825cac42 "main",
    filename = 0xffffffff825a8afe "init/main.c",
    function = 0xffffffff822000e0 <__func__.2> "run_init_process"}, {modname = 0xffffffff825cac42 "main",
    filename = 0xffffffff825a8afe "init/main.c",
    function = 0xffffffff822000e0 <__func__.2> "run_init_process"}, {modname = 0xffffffff825cac42 "main",
    filename = 0xffffffff825a8afe "init/main.c",
    function = 0xffffffff822000e0 <__func__.2> "run_init_process"}, {modname = 0xffffffff825cac42 "main",
    filename = 0xffffffff825a8afe "init/main.c",
    function = 0xffffffff822000e0 <__func__.2> "run_init_process"}, {modname = 0xffffffff825cac42 "main",
    filename = 0xffffffff825a8afe "init/main.c",
    function = 0xffffffff822000a0 <__func__.0> "initcall_blacklisted"}, {
    modname = 0xffffffff825cac42 "main", filename = 0xffffffff825a8afe "init/main.c",
    function = 0xffffffff822000c0 <__func__.1> "initcall_blacklist"}, {
    modname = 0xffffffff825cac42 "main", filename = 0xffffffff825a8ac0 "include/linux/dynamic_debug.h",
    function = 0xffffffff825cac42 "main"}}

Theres evidently something wrong with my KBUILD_MODSYM _dyndbg_site here,

the site pointers in all the headers appear the same,

but maybe its just an effect of initialization,

which I expect to reshape with a union - struct to use the space efficiently

(gdb) p *__start___dyndbg@10
$3 = {{site = 0xffffffff82b252e8 <KBUILD_MODSYM_dyndbg_site>, format = 0xffffffff825a8ab9 "head64",
    lineno = 0, flags = 0, module_index = 0, key = {dd_key_true = {key = {enabled = {counter = 0}, {
            type = 0, entries = 0x0 <fixed_percpu_data>, next = 0x0 <fixed_percpu_data>}}},
      dd_key_false = {key = {enabled = {counter = 0}, {type = 0, entries = 0x0 <fixed_percpu_data>,
            next = 0x0 <fixed_percpu_data>}}}}}, {site = 0xffffffff82b252e8 <KBUILD_MODSYM_dyndbg_site>,
    format = 0xffffffff825a8ade "ebda", lineno = 0, flags = 0, module_index = 0, key = {dd_key_true = {
        key = {enabled = {counter = 0}, {type = 0, entries = 0x0 <fixed_percpu_data>,
            next = 0x0 <fixed_percpu_data>}}}, dd_key_false = {key = {enabled = {counter = 0}, {type = 0,
            entries = 0x0 <fixed_percpu_data>, next = 0x0 <fixed_percpu_data>}}}}}, {
    site = 0xffffffff82b252e8 <KBUILD_MODSYM_dyndbg_site>, format = 0xffffffff825a8ae3 "platform_quirks",
    lineno = 0, flags = 0, module_index = 0, key = {dd_key_true = {key = {enabled = {counter = 0}, {
            type = 0, entries = 0x0 <fixed_percpu_data>, next = 0x0 <fixed_percpu_data>}}},
      dd_key_false = {key = {enabled = {counter = 0}, {type = 0, entries = 0x0 <fixed_percpu_data>,
            next = 0x0 <fixed_percpu_data>}}}}}, {
    site = 0xffffffff82b25330 <__UNIQUE_ID_ddebug468_site.13>, format = 0xffffffff82653f07 "    %s\n",
    lineno = 1349, flags = 1, module_index = 0, key = {dd_key_true = {key = {enabled = {counter = 1}, {
            type = 18446744071602861249, entries = 0xffffffff826e74c1, next = 0xffffffff826e74c1}}},
      dd_key_false = {key = {enabled = {counter = 1}, {type = 18446744071602861249,
            entries = 0xffffffff826e74c1, next = 0xffffffff826e74c1}}}}}, {
    site = 0xffffffff82b25348 <__UNIQUE_ID_ddebug467_site.15>,
    format = 0xffffffff825a8b59 "  with environment:\n", lineno = 1347, flags = 1, module_index = 0,
    key = {dd_key_true = {key = {enabled = {counter = 1}, {type = 18446744071602861265,
            entries = 0xffffffff826e74d1, next = 0xffffffff826e74d1}}}, dd_key_false = {key = {enabled = {
            counter = 1}, {type = 18446744071602861265, entries = 0xffffffff826e74d1,
            next = 0xffffffff826e74d1}}}}}, {site = 0xffffffff82b25360 <__UNIQUE_ID_ddebug466_site.17>,
    format = 0xffffffff82653f07 "    %s\n", lineno = 1346, flags = 1, module_index = 0, key = {
      dd_key_true = {key = {enabled = {counter = 1}, {type = 18446744071602861281,
            entries = 0xffffffff826e74e1, next = 0xffffffff826e74e1}}}, dd_key_false = {key = {enabled = {
            counter = 1}, {type = 18446744071602861281, entries = 0xffffffff826e74e1,
            next = 0xffffffff826e74e1}}}}}, {site = 0xffffffff82b25378 <__UNIQUE_ID_ddebug465_site.19>,
    format = 0xffffffff825a8b46 "  with arguments:\n", lineno = 1344, flags = 1, module_index = 0, key = {
      dd_key_true = {key = {enabled = {counter = 1}, {type = 18446744071602861297,