1 files changed, 16 insertions, 10 deletions

diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index 4815e5e7bb..9caeed3273 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -588,6 +588,10 @@ int erts_flush_trace_messages(Process *c_p, ErtsProcLocks c_p_locks)
     ErlTraceMessageQueue *msgq, **last_msgq;
     int reds = 0;
 
+    /* Only one thread at a time is allowed to flush trace messages,
+       so we require the main lock to be held when doing the flush */
+    ERTS_SMP_CHK_HAVE_ONLY_MAIN_PROC_LOCK(c_p);
+
     erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_TRACE);
 
     msgq = c_p->trace_msg_q;
@@ -889,26 +893,27 @@ static Eterm call_whereis(ErlNifEnv *env, Eterm name)
     Process *c_p;
     Eterm res;
     int scheduler;
-    int unlock;
 
     execution_state(env, &c_p, &scheduler);
     ASSERT((c_p && scheduler) || (!c_p && !scheduler));
 
-    unlock = 0;
     if (scheduler < 0) {
         /* dirty scheduler */
         if (ERTS_PROC_IS_EXITING(c_p))
             return 0;
 
-        if (env->proc->static_flags & ERTS_STC_FLG_SHADOW_PROC) {
-            erts_smp_proc_lock(c_p, ERTS_PROC_LOCK_MAIN);
-            unlock = 1;
-        }
+        if (env->proc->static_flags & ERTS_STC_FLG_SHADOW_PROC)
+            c_p = NULL; /* as we don't have main lock */
     }
-    res = erts_whereis_name_to_id(c_p, name);
 
-    if (unlock)
-        erts_smp_proc_unlock(c_p, ERTS_PROC_LOCK_MAIN);
+
+    if (c_p) {
+         /* main lock may be released below and c_p->htop updated by others */
+        flush_env(env);
+    }
+    res = erts_whereis_name_to_id(c_p, name);
+    if (c_p)
+        cache_env(env);
 
     return res;
 }
@@ -2456,7 +2461,8 @@ void* enif_alloc_resource(ErlNifResourceType* type, size_t data_sz)
     erts_refc_inc(&resource->type->refc, 2);
     if (type->down) {
         resource->monitors = (ErtsResourceMonitors*) (resource->data + monitors_offs);
-        erts_smp_mtx_init(&resource->monitors->lock, "resource_monitors");
+        erts_smp_mtx_init(&resource->monitors->lock, "resource_monitors", NIL,
+            ERTS_LOCK_FLAGS_CATEGORY_GENERIC);
         resource->monitors->root = NULL;
         resource->monitors->pending_failed_fire = 0;
         resource->monitors->is_dying = 0;