1 files changed, 52 insertions, 20 deletions

diff --git a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
index fa9ae1015c..a0aef60cf1 100644
--- a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
+++ b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
@@ -2140,24 +2140,45 @@ static ERL_NIF_TERM make_map_remove_nif(ErlNifEnv* env, int argc, const ERL_NIF_
 /* maps */
 static ERL_NIF_TERM maps_from_list_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[])
 {
-    ERL_NIF_TERM cell = argv[0];
-    ERL_NIF_TERM map  = enif_make_new_map(env);
-    ERL_NIF_TERM tuple;
-    const ERL_NIF_TERM *pair;
-    int arity = -1;
+    ERL_NIF_TERM *keys, *values;
+    ERL_NIF_TERM result, cell;
+    unsigned count;
 
-    if (argc != 1 && !enif_is_list(env, cell)) return enif_make_badarg(env);
+    if (argc != 1 || !enif_get_list_length(env, argv[0], &count)) {
+        return enif_make_badarg(env);
+    }
 
-    /* assume sorted keys */
+    keys = enif_alloc(sizeof(ERL_NIF_TERM) * count * 2);
+    values = keys + count;
 
-    while (!enif_is_empty_list(env,cell)) {
-	if (!enif_get_list_cell(env, cell, &tuple, &cell)) return enif_make_badarg(env);
-	if (enif_get_tuple(env,tuple,&arity,&pair)) {
-	    enif_make_map_put(env, map, pair[0], pair[1], &map);
-	}
+    cell = argv[0];
+    count = 0;
+
+    while (!enif_is_empty_list(env, cell)) {
+        const ERL_NIF_TERM *pair;
+        ERL_NIF_TERM tuple;
+        int arity;
+
+        if (!enif_get_list_cell(env, cell, &tuple, &cell)
+            || !enif_get_tuple(env, tuple, &arity, &pair)
+            || arity != 2) {
+            enif_free(keys);
+            return enif_make_badarg(env);
+        }
+
+        keys[count] = pair[0];
+        values[count] = pair[1];
+
+        count++;
+    }
+
+    if (!enif_make_map_from_arrays(env, keys, values, count, &result)) {
+        result = enif_make_atom(env, "has_duplicate_keys");
     }
 
-    return map;
+    enif_free(keys);
+
+    return result;
 }
 
 static ERL_NIF_TERM sorted_list_from_maps_nif(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[]) {
@@ -2838,7 +2859,7 @@ unsigned rand_bits(struct frenzy_rand_bits* rnd, unsigned int nbits)
 
 struct frenzy_monitor {
     ErlNifMutex* lock;
-    enum { 
+    volatile enum {
         MON_FREE, MON_FREE_DOWN, MON_FREE_DEMONITOR,
         MON_TRYING, MON_ACTIVE, MON_PENDING
     } state;
@@ -3200,13 +3221,24 @@ static void frenzy_resource_down(ErlNifEnv* env, void* obj, ErlNifPid* pid,
     DBG_TRACE3("DOWN pid=%T, r=%p rix=%u\n", pid->pid, r, r->rix);
 
     for (mix = 0; mix < FRENZY_MONITORS_MAX; mix++) {
-        if (r->monv[mix].pid.pid == pid->pid && r->monv[mix].state >= MON_TRYING) {
+        int state1 = r->monv[mix].state;
+        /* First do dirty access of pid and state without the lock */
+        if (r->monv[mix].pid.pid == pid->pid && state1 >= MON_TRYING) {
+            int state2;
             enif_mutex_lock(r->monv[mix].lock);
-            if (enif_compare_monitors(mon, &r->monv[mix].mon) == 0) {
-                assert(r->monv[mix].state >= MON_ACTIVE);
-                r->monv[mix].state = MON_FREE_DOWN;
-                enif_mutex_unlock(r->monv[mix].lock);
-                return;
+            state2 = r->monv[mix].state;
+            if (state2 >= MON_ACTIVE) {
+                if (enif_compare_monitors(mon, &r->monv[mix].mon) == 0) {
+                    r->monv[mix].state = MON_FREE_DOWN;
+                    enif_mutex_unlock(r->monv[mix].lock);
+                    return;
+                }
+            }
+            else {
+                assert(state2 != MON_TRYING);
+                assert(state1 == MON_TRYING ||  /* racing monitor failed */
+                       state2 == MON_FREE_DEMONITOR || /* racing demonitor */
+                       state2 == MON_FREE_DOWN);       /* racing down */
             }
             enif_mutex_unlock(r->monv[mix].lock);
         }