Merge branch 'sverker/ASSERT_IN_ENV'

* sverker/ASSERT_IN_ENV:
  erts: Add macro ERTS_PROC_LOCKS_HIGHER_THAN
  erts: Cleanup and extra assertions in nif_SUITE.c
  erts: Cleanup enif_make_reverse_list
  erts: Add assertions for correct ErlNifEnv
  erts: Make erts_dbg_within_proc available

# Conflicts:
#	erts/emulator/beam/erl_gc.h

8 files changed, 145 insertions, 35 deletions

diff --git a/erts/emulator/beam/erl_gc.c b/erts/emulator/beam/erl_gc.c
index 6815d76776..3a3ad820b5 100644
--- a/erts/emulator/beam/erl_gc.c
+++ b/erts/emulator/beam/erl_gc.c
@@ -3439,8 +3439,8 @@ erts_max_heap_size(Eterm arg, Uint *max_heap_size, Uint *max_heap_flags)
 
 #if defined(DEBUG) || defined(ERTS_OFFHEAP_DEBUG)
 
-static int
-within2(Eterm *ptr, Process *p, Eterm *real_htop)
+int
+erts_dbg_within_proc(Eterm *ptr, Process *p, Eterm *real_htop)
 {
     ErlHeapFragment* bp;
     ErtsMessage* mp;
@@ -3486,12 +3486,6 @@ within2(Eterm *ptr, Process *p, Eterm *real_htop)
     return 0;
 }
 
-int
-within(Eterm *ptr, Process *p)
-{
-    return within2(ptr, p, NULL);
-}
-
 #endif
 
 #ifdef ERTS_OFFHEAP_DEBUG
@@ -3546,7 +3540,7 @@ erts_check_off_heap2(Process *p, Eterm *htop)
 	else if (oheap <= u.ep && u.ep < ohtop)
 	    old = 1;
 	else {
-	    ERTS_CHK_OFFHEAP_ASSERT(within2(u.ep, p, htop));
+	    ERTS_CHK_OFFHEAP_ASSERT(erts_dbg_within_proc(u.ep, p, htop));
 	}
     }
 
diff --git a/erts/emulator/beam/erl_gc.h b/erts/emulator/beam/erl_gc.h
index f4cbe732ce..1cce426d21 100644
--- a/erts/emulator/beam/erl_gc.h
+++ b/erts/emulator/beam/erl_gc.h
@@ -67,10 +67,6 @@ do {                                                                    \
     while (nelts--) *HTOP++ = *PTR++;                                   \
 } while(0)
 
-#if defined(DEBUG) || defined(ERTS_OFFHEAP_DEBUG)
-int within(Eterm *ptr, Process *p);
-#endif
-
 #define ErtsInYoungGen(TPtr, Ptr, OldHeap, OldHeapSz)			\
     (!erts_is_literal((TPtr), (Ptr))					\
      & !ErtsInArea((Ptr), (OldHeap), (OldHeapSz)))
@@ -157,5 +153,8 @@ void erts_free_heap_frags(struct process* p);
 Eterm erts_max_heap_size_map(Sint, Uint, Eterm **, Uint *);
 int erts_max_heap_size(Eterm, Uint *, Uint *);
 void erts_deallocate_young_generation(Process *c_p);
+#if defined(DEBUG) || defined(ERTS_OFFHEAP_DEBUG)
+int erts_dbg_within_proc(Eterm *ptr, Process *p, Eterm* real_htop);
+#endif
 
 #endif /* __ERL_GC_H__ */
diff --git a/erts/emulator/beam/erl_message.c b/erts/emulator/beam/erl_message.c
index 792b69bb37..547e9cac64 100644
--- a/erts/emulator/beam/erl_message.c
+++ b/erts/emulator/beam/erl_message.c
@@ -285,9 +285,11 @@ erts_queue_dist_message(Process *rcvr,
     if (!(rcvr_locks & ERTS_PROC_LOCK_MSGQ)) {
 	if (erts_smp_proc_trylock(rcvr, ERTS_PROC_LOCK_MSGQ) == EBUSY) {
 	    ErtsProcLocks need_locks = ERTS_PROC_LOCK_MSGQ;
-	    if (rcvr_locks & ERTS_PROC_LOCK_STATUS) {
-		erts_smp_proc_unlock(rcvr, ERTS_PROC_LOCK_STATUS);
-		need_locks |= ERTS_PROC_LOCK_STATUS;
+            ErtsProcLocks unlocks =
+                rcvr_locks & ERTS_PROC_LOCKS_HIGHER_THAN(ERTS_PROC_LOCK_MSGQ);
+	    if (unlocks) {
+		erts_smp_proc_unlock(rcvr, unlocks);
+		need_locks |= unlocks;
 	    }
 	    erts_smp_proc_lock(rcvr, need_locks);
 	}
@@ -406,7 +408,7 @@ queue_messages(Process* receiver,
 	    if (state & (ERTS_PSFLG_EXITING|ERTS_PSFLG_PENDING_EXIT))
 		goto exiting;
 
-            need_locks = receiver_locks & (ERTS_PROC_LOCK_STATUS|ERTS_PROC_LOCK_TRACE);
+            need_locks = receiver_locks & ERTS_PROC_LOCKS_HIGHER_THAN(ERTS_PROC_LOCK_MSGQ);
 	    if (need_locks) {
 		erts_smp_proc_unlock(receiver, need_locks);
 	    }
diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c
index b860759fa2..47b5b23614 100644
--- a/erts/emulator/beam/erl_nif.c
+++ b/erts/emulator/beam/erl_nif.c
@@ -95,6 +95,14 @@ static void add_readonly_check(ErlNifEnv*, unsigned char* ptr, unsigned sz);
 #  define ADD_READONLY_CHECK(ENV,PTR,SIZE) ((void)0)
 #endif
 
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+#  define ASSERT_IN_ENV(ENV, TERM, NR, TYPE) dbg_assert_in_env(ENV, TERM, NR, TYPE, __func__)
+static void dbg_assert_in_env(ErlNifEnv*, Eterm term, int nr, const char* type, const char* func);
+#  include "erl_gc.h"
+#else
+#  define ASSERT_IN_ENV(ENV, TERM, NR, TYPE)
+#endif
+
 #ifdef DEBUG
 static int is_offheap(const ErlOffHeap* off_heap);
 #endif
@@ -202,6 +210,9 @@ void erts_pre_nif(ErlNifEnv* env, Process* p, struct erl_module_nif* mod_nif,
 
     ASSERT(p->common.id != ERTS_INVALID_PID);
 
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+    env->dbg_disable_assert_in_env = 0;
+#endif
 #if defined(DEBUG) && defined(ERTS_DIRTY_SCHEDULERS)
     {
 	ErtsSchedulerData *esdp = erts_get_scheduler_data();
@@ -487,11 +498,15 @@ setup_nif_env(struct enif_msg_environment_t* msg_env,
     HEAP_END(&msg_env->phony_proc) = phony_heap;
     MBUF(&msg_env->phony_proc) = NULL;
     msg_env->phony_proc.common.id = ERTS_INVALID_PID;
+    msg_env->env.tracee = tracee;
+
 #ifdef FORCE_HEAP_FRAGS
     msg_env->phony_proc.space_verified = 0;
     msg_env->phony_proc.space_verified_from = NULL;
 #endif
-    msg_env->env.tracee = tracee;
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+    msg_env->env.dbg_disable_assert_in_env = 0;
+#endif
 }
 
 ErlNifEnv* enif_alloc_env(void)
@@ -1592,6 +1607,9 @@ int enif_make_existing_atom_len(ErlNifEnv* env, const char* name, size_t len,
 
 ERL_NIF_TERM enif_make_tuple(ErlNifEnv* env, unsigned cnt, ...)
 {
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+    int nr = 0;
+#endif
     Eterm* hp = alloc_heap(env,cnt+1);
     Eterm ret = make_tuple(hp);
     va_list ap;
@@ -1599,7 +1617,9 @@ ERL_NIF_TERM enif_make_tuple(ErlNifEnv* env, unsigned cnt, ...)
     *hp++ = make_arityval(cnt);
     va_start(ap,cnt);
     while (cnt--) {
-	*hp++ = va_arg(ap,Eterm);	   
+        Eterm elem = va_arg(ap,Eterm);
+        ASSERT_IN_ENV(env, elem, ++nr, "tuple");
+	*hp++ = elem;
     }
     va_end(ap);
     return ret;
@@ -1607,12 +1627,16 @@ ERL_NIF_TERM enif_make_tuple(ErlNifEnv* env, unsigned cnt, ...)
 
 ERL_NIF_TERM enif_make_tuple_from_array(ErlNifEnv* env, const ERL_NIF_TERM arr[], unsigned cnt)
 {
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+    int nr = 0;
+#endif
     Eterm* hp = alloc_heap(env,cnt+1);
     Eterm ret = make_tuple(hp);
     const Eterm* src = arr;
 
     *hp++ = make_arityval(cnt);
     while (cnt--) {
+        ASSERT_IN_ENV(env, *src, ++nr, "tuple");
 	*hp++ = *src++;	   
     }
     return ret;
@@ -1623,6 +1647,8 @@ ERL_NIF_TERM enif_make_list_cell(ErlNifEnv* env, Eterm car, Eterm cdr)
     Eterm* hp = alloc_heap(env,2);
     Eterm ret = make_list(hp);
 
+    ASSERT_IN_ENV(env, car, 0, "head of list cell");
+    ASSERT_IN_ENV(env, cdr, 0, "tail of list cell");
     CAR(hp) = car;
     CDR(hp) = cdr;
     return ret;
@@ -1634,6 +1660,9 @@ ERL_NIF_TERM enif_make_list(ErlNifEnv* env, unsigned cnt, ...)
 	return NIL;
     }
     else {
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+        int nr = 0;
+#endif
 	Eterm* hp = alloc_heap(env,cnt*2);
 	Eterm ret = make_list(hp);
 	Eterm* last = &ret;
@@ -1641,8 +1670,10 @@ ERL_NIF_TERM enif_make_list(ErlNifEnv* env, unsigned cnt, ...)
 
 	va_start(ap,cnt);
 	while (cnt--) {
+            Eterm term = va_arg(ap,Eterm);
 	    *last = make_list(hp);
-	    *hp = va_arg(ap,Eterm);
+            ASSERT_IN_ENV(env, term, ++nr, "list");
+	    *hp = term;
 	    last = ++hp;
 	    ++hp;
 	}
@@ -1654,14 +1685,19 @@ ERL_NIF_TERM enif_make_list(ErlNifEnv* env, unsigned cnt, ...)
 
 ERL_NIF_TERM enif_make_list_from_array(ErlNifEnv* env, const ERL_NIF_TERM arr[], unsigned cnt)
 {
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+    int nr = 0;
+#endif
     Eterm* hp = alloc_heap(env,cnt*2);
     Eterm ret = make_list(hp);
     Eterm* last = &ret;
     const Eterm* src = arr;
 
     while (cnt--) {
+        Eterm term = *src++;
 	*last = make_list(hp);
-	*hp = *src++;
+        ASSERT_IN_ENV(env, term, ++nr, "list");
+	*hp = term;
 	last = ++hp;
 	++hp;
     }
@@ -1694,13 +1730,9 @@ void enif_system_info(ErlNifSysInfo *sip, size_t si_size)
     driver_system_info(sip, si_size);
 }
 
-int enif_make_reverse_list(ErlNifEnv* env, ERL_NIF_TERM term, ERL_NIF_TERM *list) {
-    Eterm *listptr, ret = NIL, *hp;
-
-    if (is_nil(term)) {
-	*list = term;
-        return 1;
-    }
+int enif_make_reverse_list(ErlNifEnv* env, ERL_NIF_TERM term, ERL_NIF_TERM *list)
+{
+    Eterm *listptr, ret, *hp;
 
     ret = NIL;
 
@@ -2584,6 +2616,10 @@ int enif_make_map_put(ErlNifEnv* env,
     if (!is_map(map_in)) {
 	return 0;
     }
+    ASSERT_IN_ENV(env, map_in, 0, "old map");
+    ASSERT_IN_ENV(env, key, 0, "key");
+    ASSERT_IN_ENV(env, value, 0, "value");
+
     flush_env(env);
     *map_out = erts_maps_put(env->proc, key, value, map_in);
     cache_env(env);
@@ -2618,6 +2654,10 @@ int enif_make_map_update(ErlNifEnv* env,
 	return 0;
     }
 
+    ASSERT_IN_ENV(env, map_in, 0, "old map");
+    ASSERT_IN_ENV(env, key, 0, "key");
+    ASSERT_IN_ENV(env, value, 0, "value");
+
     flush_env(env);
     res = erts_maps_update(env->proc, key, value, map_in, map_out);
     cache_env(env);
@@ -3338,6 +3378,9 @@ Eterm erts_nif_call_function(Process *p, Process *tracee,
         clear_offheap(&MSO(p));
 
         erts_pre_nif(&env, p, mod, tracee);
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+        env.dbg_disable_assert_in_env = 1;
+#endif
         nif_result = (*fun->fptr)(&env, argc, argv);
         if (env.exception_thrown)
             nif_result = THE_NON_VALUE;
@@ -3360,6 +3403,9 @@ Eterm erts_nif_call_function(Process *p, Process *tracee,
            so we create a phony one. */
         struct enif_msg_environment_t msg_env;
         pre_nif_noproc(&msg_env, mod, tracee);
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+        msg_env.env.dbg_disable_assert_in_env = 1;
+#endif
         nif_result = (*fun->fptr)(&msg_env.env, argc, argv);
         if (msg_env.env.exception_thrown)
             nif_result = THE_NON_VALUE;
@@ -3424,6 +3470,55 @@ static unsigned calc_checksum(unsigned char* ptr, unsigned size)
 
 #endif /* READONLY_CHECK */
 
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+static void dbg_assert_in_env(ErlNifEnv* env, Eterm term,
+                              int nr, const char* type, const char* func)
+{
+    Uint saved_used_size;
+    Eterm* real_htop;
+
+    if (is_immed(term)
+        || (is_non_value(term) && env->exception_thrown)
+        || erts_is_literal(term, ptr_val(term)))
+        return;
+
+    if (env->dbg_disable_assert_in_env) {
+        /*
+         * Trace nifs may cheat as built terms are discarded after return.
+         * ToDo: Check if 'term' is part of argv[].
+         */
+        return;
+    }
+
+    if (env->heap_frag) {
+        ASSERT(env->heap_frag == MBUF(env->proc));
+        ASSERT(env->hp >= env->heap_frag->mem);
+        ASSERT(env->hp <= env->heap_frag->mem + env->heap_frag->alloc_size);
+        saved_used_size = env->heap_frag->used_size;
+        env->heap_frag->used_size = env->hp - env->heap_frag->mem;
+        real_htop = NULL;
+    }
+    else {
+        real_htop = env->hp;
+    }
+    if (!erts_dbg_within_proc(ptr_val(term), env->proc, real_htop)) {
+        fprintf(stderr, "\r\nFAILED ASSERTION in %s:\r\n", func);
+        if (nr) {
+            fprintf(stderr, "Term #%d of the %s is not from same ErlNifEnv.",
+                    nr, type);
+        }
+        else {
+            fprintf(stderr, "The %s is not from the same ErlNifEnv.", type);
+        }
+        fprintf(stderr, "\r\nABORTING\r\n");
+        abort();
+    }
+    if (env->heap_frag) {
+        env->heap_frag->used_size = saved_used_size;
+    }
+}
+#endif
+
 #ifdef HAVE_USE_DTRACE
 
 #define MESSAGE_BUFSIZ 1024
diff --git a/erts/emulator/beam/erl_process_lock.h b/erts/emulator/beam/erl_process_lock.h
index 773529384f..46a72fcb0c 100644
--- a/erts/emulator/beam/erl_process_lock.h
+++ b/erts/emulator/beam/erl_process_lock.h
@@ -219,6 +219,10 @@ typedef struct erts_proc_lock_t_ {
 #define ERTS_PROC_LOCKS_ALL_MINOR	(ERTS_PROC_LOCKS_ALL \
                                          & ~ERTS_PROC_LOCK_MAIN)
 
+/* All locks we first must unlock to lock L */
+#define ERTS_PROC_LOCKS_HIGHER_THAN(L) \
+  (ERTS_PROC_LOCKS_ALL & (~(L) & ~((L)-1)))
+
 
 #define ERTS_PIX_LOCKS_BITS		10
 #define ERTS_NO_OF_PIX_LOCKS		(1 << ERTS_PIX_LOCKS_BITS)
diff --git a/erts/emulator/beam/global.h b/erts/emulator/beam/global.h
index d5ca3b04eb..c39ac2f7ec 100644
--- a/erts/emulator/beam/global.h
+++ b/erts/emulator/beam/global.h
@@ -45,6 +45,9 @@
 
 struct enif_func_t;
 
+#ifdef  DEBUG
+#  define ERTS_NIF_ASSERT_IN_ENV
+#endif
 struct enif_environment_t /* ErlNifEnv */
 {
     struct erl_module_nif* mod_nif;
@@ -57,6 +60,10 @@ struct enif_environment_t /* ErlNifEnv */
     int exception_thrown; /* boolean */
     Process *tracee;
     int exiting; /* boolean (dirty nifs might return in exiting state) */
+
+#ifdef ERTS_NIF_ASSERT_IN_ENV
+    int dbg_disable_assert_in_env;
+#endif
 };
 extern void erts_pre_nif(struct enif_environment_t*, Process*,
 			 struct erl_module_nif*, Process* tracee);
diff --git a/erts/emulator/hipe/hipe_gc.c b/erts/emulator/hipe/hipe_gc.c
index e6ce7ce628..cf0435adc9 100644
--- a/erts/emulator/hipe/hipe_gc.c
+++ b/erts/emulator/hipe/hipe_gc.c
@@ -99,7 +99,7 @@ Eterm *fullsweep_nstack(Process *p, Eterm *n_htop)
 		    if (IS_MOVED_CONS(val)) {
 			*nsp_i = ptr[1];
 		    } else if (!erts_is_literal(gval, ptr)) {
-			ASSERT(within(ptr, p));
+			ASSERT(erts_dbg_within_proc(ptr, p, NULL));
 			MOVE_CONS(ptr, val, n_htop, nsp_i);
 		    }
 		}
@@ -208,7 +208,7 @@ void gensweep_nstack(Process *p, Eterm **ptr_old_htop, Eterm **ptr_n_htop)
 		    } else if (ErtsInArea(ptr, mature, mature_size)) {
 			MOVE_BOXED(ptr, val, old_htop, nsp_i);
 		    } else if (ErtsInYoungGen(gval, ptr, oh, oh_size)) {
-			ASSERT(within(ptr, p));
+			ASSERT(erts_dbg_within_proc(ptr, p, NULL));
 			MOVE_BOXED(ptr, val, n_htop, nsp_i);
 		    }
 		} else if (is_list(gval)) {
@@ -219,7 +219,7 @@ void gensweep_nstack(Process *p, Eterm **ptr_old_htop, Eterm **ptr_n_htop)
 		    } else if (ErtsInArea(ptr, mature, mature_size)) {
 			MOVE_CONS(ptr, val, old_htop, nsp_i);
 		    } else if (ErtsInYoungGen(gval, ptr, oh, oh_size)) {
-			ASSERT(within(ptr, p));
+			ASSERT(erts_dbg_within_proc(ptr, p, NULL));
 			MOVE_CONS(ptr, val, n_htop, nsp_i);
 		    }
 		}
diff --git a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
index 2c93891852..4decb7f418 100644
--- a/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
+++ b/erts/emulator/test/nif_SUITE_data/nif_SUITE.c
@@ -116,7 +116,6 @@ static ERL_NIF_TERM make_pointer(ErlNifEnv* env, void* p)
 {
     void** bin_data;
     ERL_NIF_TERM res;
-    ADD_CALL("get_priv_data_ptr");
     bin_data = (void**)enif_make_new_binary(env, sizeof(void*), &res);
     *bin_data = p;
     return res;
@@ -389,8 +388,7 @@ static ERL_NIF_TERM type_test(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[
     ErlNifSInt64 sint64;
     ErlNifUInt64 uint64;
     double d;
-    ERL_NIF_TERM atom, ref1, ref2, term;
-    size_t len;
+    ERL_NIF_TERM atom, ref1, ref2;
 
     sint = INT_MIN;
     do {
@@ -1024,6 +1022,7 @@ struct make_term_info
 {
     ErlNifEnv* caller_env;
     ErlNifEnv* dst_env;
+    int dst_env_valid;
     ERL_NIF_TERM reuse[MAKE_TERM_REUSE_LEN];
     unsigned reuse_push;
     unsigned reuse_pull;
@@ -1053,6 +1052,7 @@ static ERL_NIF_TERM pull_term(struct make_term_info* mti)
 	mti->reuse_push < MAKE_TERM_REUSE_LEN) {
 	mti->reuse_pull = 0;
 	if (mti->reuse_push == 0) {
+            assert(mti->dst_env_valid);
 	    mti->reuse[0] = enif_make_list(mti->dst_env, 0);
 	}
     }
@@ -1241,6 +1241,7 @@ static unsigned num_of_make_funcs()
 static int make_term_n(struct make_term_info* mti, int n, ERL_NIF_TERM* res)
 {
     if (n < num_of_make_funcs()) {
+        assert(mti->dst_env_valid);
 	*res = make_funcs[n](mti, n);
 	push_term(mti, *res);
 	return 1;
@@ -1257,6 +1258,7 @@ static ERL_NIF_TERM make_blob(ErlNifEnv* caller_env, ErlNifEnv* dst_env,
     struct make_term_info mti;
     mti.caller_env = caller_env;
     mti.dst_env = dst_env;
+    mti.dst_env_valid = 1;
     mti.reuse_push = 0;
     mti.reuse_pull = 0;
     mti.resource_type = priv->rt_arr[0].t;
@@ -1297,6 +1299,7 @@ static ERL_NIF_TERM alloc_msgenv(ErlNifEnv* env, int argc, const ERL_NIF_TERM ar
 						       sizeof(*mti));
     mti->caller_env = NULL;
     mti->dst_env = enif_alloc_env();
+    mti->dst_env_valid = 1;
     mti->reuse_push = 0;
     mti->reuse_pull = 0;
     mti->resource_type = priv->rt_arr[0].t;
@@ -1328,6 +1331,7 @@ static ERL_NIF_TERM clear_msgenv(ErlNifEnv* env, int argc, const ERL_NIF_TERM ar
 	return enif_make_badarg(env);
     }
     enif_clear_env(mti.p->dst_env);
+    mti.p->dst_env_valid = 1;
     mti.p->reuse_pull = 0;
     mti.p->reuse_push = 0;
     mti.p->blob = enif_make_list(mti.p->dst_env, 0);
@@ -1362,6 +1366,8 @@ static ERL_NIF_TERM send_blob(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv[
     }
     copy = enif_make_copy(env, mti.p->blob);
     res = enif_send(env, &to, mti.p->dst_env, mti.p->blob);
+    if (res)
+        mti.p->dst_env_valid = 0;
     return enif_make_tuple3(env, atom_ok, enif_make_int(env,res), copy);
 }
 
@@ -1369,7 +1375,6 @@ static ERL_NIF_TERM send3_blob(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv
 {
     mti_t mti;
     ErlNifPid to;
-    ERL_NIF_TERM copy;
     int res;
     if (!enif_get_resource(env, argv[0], msgenv_resource_type, &mti.vp)
 	|| !enif_get_local_pid(env, argv[1], &to)) {
@@ -1379,6 +1384,8 @@ static ERL_NIF_TERM send3_blob(ErlNifEnv* env, int argc, const ERL_NIF_TERM argv
 				   enif_make_copy(mti.p->dst_env, argv[2]),
 				   mti.p->blob);
     res = enif_send(env, &to, mti.p->dst_env, mti.p->blob);
+    if (res)
+        mti.p->dst_env_valid = 0;
     return enif_make_int(env,res);
 }
 
@@ -1395,6 +1402,8 @@ void* threaded_sender(void *arg)
     mti.p->send_it = 0;
     enif_mutex_unlock(mti.p->mtx);
     mti.p->send_res = enif_send(NULL, &mti.p->to_pid, mti.p->dst_env, mti.p->blob);
+    if (mti.p->send_res)
+        mti.p->dst_env_valid = 0;
     return NULL;
 }