test: use global_snab_kc_pid

fix lock_order_violation when run with debug emu type
````
    at beam/erl_lock_check.c:1225
    at beam/erl_threads.h:1991
````

c_src/quicer_nif.c

@@ -1142,6 +1142,10 @@ on_load(ErlNifEnv *env,
 
   init_atoms(env);
 
+#if defined(QUICER_USE_SNK)
+  enif_set_pid_undefined(&GLOBAL_SNAB_KC_PID);
+#endif
+
   // TP must run after init_atoms as atoms are used in TP
   TP_NIF_3(start, &MsQuic, 0);
   if (!enif_get_uint(env, loadinfo, &load_vsn))
@@ -1738,7 +1742,11 @@ static ErlNifFunc nif_funcs[] = {
   { "get_stream_owner", 1, get_stream_owner1, 0},
   { "get_listener_owner", 1, get_listener_owner1, 0},
   /* for testing */
-  { "mock_buffer_sig", 3, mock_buffer_sig, 0}
+  { "mock_buffer_sig", 3, mock_buffer_sig, 0},
+  #ifdef QUICER_USE_SNK
+  { "set_snab_kc_pid", 1, set_snab_kc_pid, 0},
+  { "get_snab_kc_pid", 0, get_snab_kc_pid, 0},
+  #endif
   // clang-format on
 };
 

c_src/quicer_tp.c

@@ -1,12 +1,42 @@
 #define TRACEPOINT_CREATE_PROBES
 #define TRACEPOINT_DEFINE
 #include "quicer_tp.h"
+#include "assert.h"
 
 extern uint64_t CxPlatTimeUs64(void);
+// Compiler attributes
+#define __unused_parm__ __attribute__((unused))
+
+// Global pid for snabbkaffe collector
+ErlNifPid GLOBAL_SNAB_KC_PID;
 
 // help macro to copy atom to env for debug emulator assertions
 #define ATOM_IN_ENV(X) enif_make_copy(env, ATOM_##X)
 
+// This is a helper function to set the pid of the snabbkaffe collector
+// because enif_whereis_pid in resource dtor violates beam lock orderings.
+ERL_NIF_TERM
+set_snab_kc_pid(ErlNifEnv *env,
+                __unused_parm__ int argc,
+                const ERL_NIF_TERM argv[])
+{
+  assert(argc == 1);
+  if (!enif_get_local_pid(env, argv[0], &GLOBAL_SNAB_KC_PID))
+    {
+      return ERROR_TUPLE_2(ATOM_BADARG);
+    }
+  return ATOM_OK;
+}
+
+ERL_NIF_TERM
+get_snab_kc_pid(ErlNifEnv *env,
+                __unused_parm__ int argc,
+                __unused_parm__ const ERL_NIF_TERM argv[])
+{
+  assert(argc == 0);
+  return enif_make_pid(env, &GLOBAL_SNAB_KC_PID);
+}
+
 void
 tp_snk(ErlNifEnv *env,
        const char *ctx,
@@ -15,45 +45,40 @@ tp_snk(ErlNifEnv *env,
        uint64_t rid,
        uint64_t mark)
 {
-  ErlNifPid pid;
-  if (enif_whereis_pid(env, ATOM_SNABBKAFFE_COLLECTOR, &pid))
-    {
-      ERL_NIF_TERM snk_event;
-      ERL_NIF_TERM snk_event_key_array[7]
-          = { ATOM_IN_ENV(SNK_KIND),    ATOM_IN_ENV(CONTEXT),
-              ATOM_IN_ENV(FUNCTION),    ATOM_IN_ENV(TAG),
-              ATOM_IN_ENV(RESOURCE_ID), ATOM_IN_ENV(MARK),
-              ATOM_IN_ENV(SNK_META) };
-
-      ERL_NIF_TERM snk_evt_meta;
-      ERL_NIF_TERM snk_evt_meta_key_array[1] = { ATOM_IN_ENV(TIME) };
-      ERL_NIF_TERM snk_evt_meta_val_array[1]
-          = { enif_make_uint64(env, CxPlatTimeUs64()) };
-
-      // shall never fail
-      enif_make_map_from_arrays(env,
-                                snk_evt_meta_key_array,
-                                snk_evt_meta_val_array,
-                                1,
-                                &snk_evt_meta);
-
-      ERL_NIF_TERM snk_event_val_array[7] = {
-        ATOM_IN_ENV(DEBUG),                         // snk_kind
-        enif_make_string(env, ctx, ERL_NIF_LATIN1), // context
-        enif_make_string(env, fun, ERL_NIF_LATIN1), // fun
-        enif_make_string(env, tag, ERL_NIF_LATIN1), // tag
-        enif_make_uint64(env, rid),                 // rid
-        enif_make_uint64(env, mark),                // mark
-        snk_evt_meta                                // snk_meta
-      };
-
-      enif_make_map_from_arrays(
-          env, snk_event_key_array, snk_event_val_array, 7, &snk_event);
-
-      ERL_NIF_TERM report = enif_make_tuple2(
-          env,
-          ATOM_IN_ENV(GEN_CAST),
-          enif_make_tuple2(env, ATOM_IN_ENV(TRACE), snk_event));
-      enif_send(NULL, &pid, NULL, report);
-    }
+  ErlNifPid *pid = &GLOBAL_SNAB_KC_PID;
+
+  ERL_NIF_TERM snk_event;
+  ERL_NIF_TERM snk_event_key_array[7]
+      = { ATOM_IN_ENV(SNK_KIND),    ATOM_IN_ENV(CONTEXT),
+          ATOM_IN_ENV(FUNCTION),    ATOM_IN_ENV(TAG),
+          ATOM_IN_ENV(RESOURCE_ID), ATOM_IN_ENV(MARK),
+          ATOM_IN_ENV(SNK_META) };
+
+  ERL_NIF_TERM snk_evt_meta;
+  ERL_NIF_TERM snk_evt_meta_key_array[1] = { ATOM_IN_ENV(TIME) };
+  ERL_NIF_TERM snk_evt_meta_val_array[1]
+      = { enif_make_uint64(env, CxPlatTimeUs64()) };
+
+  // shall never fail
+  enif_make_map_from_arrays(
+      env, snk_evt_meta_key_array, snk_evt_meta_val_array, 1, &snk_evt_meta);
+
+  ERL_NIF_TERM snk_event_val_array[7] = {
+    ATOM_IN_ENV(DEBUG),                         // snk_kind
+    enif_make_string(env, ctx, ERL_NIF_LATIN1), // context
+    enif_make_string(env, fun, ERL_NIF_LATIN1), // fun
+    enif_make_string(env, tag, ERL_NIF_LATIN1), // tag
+    enif_make_uint64(env, rid),                 // rid
+    enif_make_uint64(env, mark),                // mark
+    snk_evt_meta                                // snk_meta
+  };
+
+  enif_make_map_from_arrays(
+      env, snk_event_key_array, snk_event_val_array, 7, &snk_event);
+
+  ERL_NIF_TERM report
+      = enif_make_tuple2(env,
+                         ATOM_IN_ENV(GEN_CAST),
+                         enif_make_tuple2(env, ATOM_IN_ENV(TRACE), snk_event));
+  enif_send(NULL, pid, NULL, report);
 }

c_src/quicer_tp.h

@@ -54,6 +54,7 @@ TRACEPOINT_EVENT(
 /* END of ifdef QUICER_USE_LTTNG */
 
 #elif defined(QUICER_USE_SNK)
+extern ErlNifPid GLOBAL_SNAB_KC_PID;
 
 #define TP_NIF_3(TAG, RID, ARG)                                               \
   tp_snk(env, "nif", __func__, #TAG, (uint64_t)RID, ARG)
@@ -66,6 +67,11 @@ void tp_snk(ErlNifEnv *env,
             const char *tag,
             uint64_t rid,
             uint64_t mark);
+
+ERL_NIF_TERM
+set_snab_kc_pid(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]);
+ERL_NIF_TERM
+get_snab_kc_pid(ErlNifEnv *env, int argc, const ERL_NIF_TERM argv[]);
 /* END of ifdef QUICER_USE_SNK */
 #else /* NO TP is defined */
 

src/quicer_nif.erl

@@ -65,7 +65,9 @@
     get_conn_owner/1,
     get_stream_owner/1,
     get_listener_owner/1,
-    mock_buffer_sig/3
+    mock_buffer_sig/3,
+    set_snab_kc_pid/1,
+    get_snab_kc_pid/0
 ]).
 
 -export([abi_version/0]).
@@ -405,6 +407,14 @@ flush_stream_buffered_sigs(_H) ->
 mock_buffer_sig(_StreamHandle, _OrigOwner, _Msg) ->
     erlang:nif_error(nif_library_not_loaded).
 
+-spec set_snab_kc_pid(pid()) -> ok | {error, badarg}.
+set_snab_kc_pid(_Pid) ->
+    erlang:nif_error(nif_library_not_loaded).
+
+-spec get_snab_kc_pid() -> pid().
+get_snab_kc_pid() ->
+    erlang:nif_error(nif_library_not_loaded).
+
 %% Internals
 -spec locate_lib(file:name(), file:name()) ->
     {ok, file:filename()} | {error, not_found}.