Ensure reply signals from ports respect signal order

The reply signal from a port to a process, when the process called one of the
'port_*' BIFs, could pass before other signals sent from the port to the
process. That is, the reply signal could be delivered too early.

4 files changed, 283 insertions, 163 deletions

diff --git a/erts/emulator/beam/atom.names b/erts/emulator/beam/atom.names
index ceb8c56623..d7bcf61a53 100644
--- a/erts/emulator/beam/atom.names
+++ b/erts/emulator/beam/atom.names
@@ -119,6 +119,7 @@ atom badarg badarith badarity badfile badfun badkey badmap badmatch badsig
 atom bag
 atom band
 atom big
+atom bif_handle_signals_return
 atom bif_return_trap
 atom binary
 atom binary_copy_trap
diff --git a/erts/emulator/beam/bif.c b/erts/emulator/beam/bif.c
index 000397e790..b9cce0022d 100644
--- a/erts/emulator/beam/bif.c
+++ b/erts/emulator/beam/bif.c
@@ -4847,7 +4847,50 @@ static BIF_RETTYPE bif_return_trap(BIF_ALIST_2)
     BIF_RET(res);
 }
 
+static BIF_RETTYPE
+bif_handle_signals_return(BIF_ALIST_1)
+{
+    int local_only = BIF_P->flags & F_LOCAL_SIGS_ONLY;
+    int sres, sreds, reds_left;
+    erts_aint32_t state;
+
+    reds_left = ERTS_BIF_REDS_LEFT(BIF_P);
+    sreds = reds_left;
+
+    if (!local_only) {
+        erts_proc_lock(BIF_P, ERTS_PROC_LOCK_MSGQ);
+        erts_proc_sig_fetch(BIF_P);
+        erts_proc_unlock(BIF_P, ERTS_PROC_LOCK_MSGQ);
+    }
+
+    state = erts_atomic32_read_nob(&BIF_P->state);
+    sres = erts_proc_sig_handle_incoming(BIF_P, &state, &sreds,
+                                         sreds, !0);
+
+    BUMP_REDS(BIF_P, (int) sreds);
+    reds_left -= sreds;
+
+    if (state & ERTS_PSFLG_EXITING) {
+        BIF_P->flags &= ~F_LOCAL_SIGS_ONLY;
+        ERTS_BIF_EXITED(BIF_P);
+    }
+    if (!sres | (reds_left <= 0)) {
+        /*
+         * More signals to handle or out of reds; need
+         * to yield and continue. Prevent fetching of
+         * more signals by setting local-sigs-only flag.
+         */
+        BIF_P->flags |= F_LOCAL_SIGS_ONLY;
+        ERTS_BIF_YIELD1(&erts_bif_handle_signals_return_export,
+                        BIF_P, BIF_ARG_1);
+    }
+
+    BIF_P->flags &= ~F_LOCAL_SIGS_ONLY;
+    BIF_RET(BIF_ARG_1);
+}
+
 Export bif_return_trap_export;
+Export erts_bif_handle_signals_return_export;
 
 void erts_init_trap_export(Export* ep, Eterm m, Eterm f, Uint a,
 			   Eterm (*bif)(BIF_ALIST))
@@ -4874,6 +4917,10 @@ void erts_init_bif(void)
 			  am_erlang, am_bif_return_trap, 2,
 			  &bif_return_trap);
 
+    erts_init_trap_export(&erts_bif_handle_signals_return_export,
+			  am_erlang, am_bif_handle_signals_return, 1,
+			  &bif_handle_signals_return);
+
     erts_await_result = erts_export_put(am_erts_internal,
 					am_await_result,
 					1);
diff --git a/erts/emulator/beam/bif.h b/erts/emulator/beam/bif.h
index cf9f61c0b8..bad047b92f 100644
--- a/erts/emulator/beam/bif.h
+++ b/erts/emulator/beam/bif.h
@@ -462,6 +462,15 @@ do {									\
     BIF_TRAP4((TRP), (P), (A0), (A1), (A2), (A3));                      \
 } while (0)
 
+extern Export erts_bif_handle_signals_return_export;
+
+#define ERTS_BIF_HANDLE_SIGNALS_RETURN(P, VAL)                          \
+    BIF_TRAP1(&erts_bif_handle_signals_return_export, (P), (VAL))
+
+#define ERTS_BIF_PREP_HANDLE_SIGNALS_RETURN(Ret, P, Val)                \
+    ERTS_BIF_PREP_TRAP1((Ret), &erts_bif_handle_signals_return_export,  \
+                        (P), (Val))
+
 #define ERTS_BIF_PREP_EXITED(RET, PROC)	                                \
 do {                                                                    \
     KILL_CATCHES((PROC));                                               \
diff --git a/erts/emulator/beam/erl_bif_port.c b/erts/emulator/beam/erl_bif_port.c
index ed825d3dda..40a2fb96d6 100644
--- a/erts/emulator/beam/erl_bif_port.c
+++ b/erts/emulator/beam/erl_bif_port.c
@@ -167,7 +167,7 @@ BIF_RETTYPE erts_internal_port_command_3(BIF_ALIST_3)
     BIF_RETTYPE res;
     Port *prt;
     int flags = 0;
-    Eterm ref;
+    erts_aint32_t state;
 
     if (is_not_nil(BIF_ARG_3)) {
 	Eterm l = BIF_ARG_3;
@@ -188,51 +188,59 @@ BIF_RETTYPE erts_internal_port_command_3(BIF_ALIST_3)
 
     prt = sig_lookup_port(BIF_P, BIF_ARG_1);
     if (!prt)
-	BIF_RET(am_badarg);
-
-    if (flags & ERTS_PORT_SIG_FLG_FORCE) {
-	if (!(prt->drv_ptr->flags & ERL_DRV_FLAG_SOFT_BUSY))
-	    BIF_RET(am_notsup);
+        ERTS_BIF_PREP_RET(res, am_badarg);
+    else if ((flags & ERTS_PORT_SIG_FLG_FORCE)
+             && !(prt->drv_ptr->flags & ERL_DRV_FLAG_SOFT_BUSY)) {
+        ERTS_BIF_PREP_RET(res, am_notsup);
     }
-
+    else {
+        Eterm ref;
 #ifdef DEBUG
-    ref = NIL;
+        ref = NIL;
 #endif
 
-    switch (erts_port_output(BIF_P, flags, prt, prt->common.id, BIF_ARG_2, &ref)) {
-    case ERTS_PORT_OP_BADARG:
-    case ERTS_PORT_OP_DROPPED:
- 	ERTS_BIF_PREP_RET(res, am_badarg);
-	break;
-    case ERTS_PORT_OP_BUSY:
-	ASSERT(!(flags & ERTS_PORT_SIG_FLG_FORCE));
-	if (flags & ERTS_PORT_SIG_FLG_NOSUSPEND)
-	    ERTS_BIF_PREP_RET(res, am_false);
-	else {
-	    erts_suspend(BIF_P, ERTS_PROC_LOCK_MAIN, prt);
-	    ERTS_BIF_PREP_YIELD3(res, bif_export[BIF_erts_internal_port_command_3],
-				 BIF_P, BIF_ARG_1, BIF_ARG_2, BIF_ARG_3);
-	}
-	break;
-    case ERTS_PORT_OP_BUSY_SCHEDULED:
-	ASSERT(!(flags & ERTS_PORT_SIG_FLG_FORCE));
-	/* Fall through... */
-    case ERTS_PORT_OP_SCHEDULED:
-	ASSERT(is_internal_ordinary_ref(ref));
-	ERTS_BIF_PREP_RET(res, ref);
-	break;
-    case ERTS_PORT_OP_DONE:
-	ERTS_BIF_PREP_RET(res, am_true);
-	break;
-    default:
-	ERTS_INTERNAL_ERROR("Unexpected erts_port_output() result");
-	break;
+        switch (erts_port_output(BIF_P, flags, prt, prt->common.id,
+                                 BIF_ARG_2, &ref)) {
+        case ERTS_PORT_OP_BADARG:
+        case ERTS_PORT_OP_DROPPED:
+            ERTS_BIF_PREP_RET(res, am_badarg);
+            break;
+        case ERTS_PORT_OP_BUSY:
+            ASSERT(!(flags & ERTS_PORT_SIG_FLG_FORCE));
+            if (flags & ERTS_PORT_SIG_FLG_NOSUSPEND)
+                ERTS_BIF_PREP_RET(res, am_false);
+            else {
+                erts_suspend(BIF_P, ERTS_PROC_LOCK_MAIN, prt);
+                ERTS_BIF_PREP_YIELD3(res, bif_export[BIF_erts_internal_port_command_3],
+                                     BIF_P, BIF_ARG_1, BIF_ARG_2, BIF_ARG_3);
+            }
+            break;
+        case ERTS_PORT_OP_BUSY_SCHEDULED:
+            ASSERT(!(flags & ERTS_PORT_SIG_FLG_FORCE));
+            /* Fall through... */
+        case ERTS_PORT_OP_SCHEDULED:
+            ASSERT(is_internal_ordinary_ref(ref));
+            BIF_RET(ref);
+        case ERTS_PORT_OP_DONE:
+            ERTS_BIF_PREP_RET(res, am_true);
+            break;
+        default:
+            ERTS_INTERNAL_ERROR("Unexpected erts_port_output() result");
+            ERTS_BIF_PREP_RET(res, am_internal_error);
+            break;
+        }
     }
 
-    if (ERTS_PROC_IS_EXITING(BIF_P)) {
+    state = erts_atomic32_read_acqb(&BIF_P->state);
+    if (state & ERTS_PSFLG_EXITING) {
 	KILL_CATCHES(BIF_P);	/* Must exit */
 	ERTS_BIF_PREP_ERROR(res, BIF_P, EXC_ERROR);
     }
+    else {
+        /* Ensure signal order is preserved... */
+        if (state & (ERTS_PSFLG_SIG_Q|ERTS_PSFLG_SIG_IN_Q))
+            ERTS_BIF_PREP_HANDLE_SIGNALS_RETURN(res, BIF_P, res);
+    }
 
     return res;
 }
@@ -242,41 +250,46 @@ BIF_RETTYPE erts_internal_port_call_3(BIF_ALIST_3)
     Port* prt;
     Eterm retval;
     Uint uint_op;
-    unsigned int op;
     erts_aint32_t state;
 
     prt = sig_lookup_port(BIF_P, BIF_ARG_1);
     if (!prt)
-	BIF_RET(am_badarg);
-
-    if (!term_to_Uint(BIF_ARG_2, &uint_op))
-	BIF_RET(am_badarg);
-
-    if (uint_op > (Uint) UINT_MAX)
-	BIF_RET(am_badarg);
-
-    op = (unsigned int) uint_op;
-
-    switch (erts_port_call(BIF_P, prt, op, BIF_ARG_3, &retval)) {
-    case ERTS_PORT_OP_DROPPED:
-    case ERTS_PORT_OP_BADARG:
 	retval = am_badarg;
-	break;
-    case ERTS_PORT_OP_SCHEDULED:
-	ASSERT(is_internal_ordinary_ref(retval));
-	break;
-    case ERTS_PORT_OP_DONE:
-	ASSERT(is_not_internal_ref(retval));
-	break;
-    default:
-	ERTS_INTERNAL_ERROR("Unexpected erts_port_call() result");
-	retval = am_internal_error;
-	break;
+    else if (!term_to_Uint(BIF_ARG_2, &uint_op))
+	retval = am_badarg;
+    else if (uint_op > (Uint) UINT_MAX)
+	retval = am_badarg;
+    else {
+        unsigned int op = (unsigned int) uint_op;
+
+        switch (erts_port_call(BIF_P, prt, op, BIF_ARG_3, &retval)) {
+        case ERTS_PORT_OP_DROPPED:
+        case ERTS_PORT_OP_BADARG:
+            retval = am_badarg;
+            break;
+        case ERTS_PORT_OP_SCHEDULED:
+            ASSERT(is_internal_ordinary_ref(retval));
+            /* Signal order preserved by reply... */
+            BIF_RET(retval);
+            break;
+        case ERTS_PORT_OP_DONE:
+            ASSERT(is_not_internal_ref(retval));
+            break;
+        default:
+            ERTS_INTERNAL_ERROR("Unexpected erts_port_call() result");
+            retval = am_internal_error;
+            break;
+        }
     }
 
     state = erts_atomic32_read_acqb(&BIF_P->state);
     if (state & ERTS_PSFLG_EXITING)
 	ERTS_BIF_EXITED(BIF_P);
+    else {
+        /* Ensure signal order is preserved... */
+        if (state & (ERTS_PSFLG_SIG_Q|ERTS_PSFLG_SIG_IN_Q))
+            ERTS_BIF_HANDLE_SIGNALS_RETURN(BIF_P, retval);
+    }
 
     BIF_RET(retval);
 }
@@ -286,41 +299,45 @@ BIF_RETTYPE erts_internal_port_control_3(BIF_ALIST_3)
     Port* prt;
     Eterm retval;
     Uint uint_op;
-    unsigned int op;
     erts_aint32_t state;
 
     prt = sig_lookup_port(BIF_P, BIF_ARG_1);
     if (!prt)
-	BIF_RET(am_badarg);
-
-    if (!term_to_Uint(BIF_ARG_2, &uint_op))
-	BIF_RET(am_badarg);
-
-    if (uint_op > (Uint) UINT_MAX)
-	BIF_RET(am_badarg);
-
-    op = (unsigned int) uint_op;
-
-    switch (erts_port_control(BIF_P, prt, op, BIF_ARG_3, &retval)) {
-    case ERTS_PORT_OP_BADARG:
-    case ERTS_PORT_OP_DROPPED:
 	retval = am_badarg;
-	break;
-    case ERTS_PORT_OP_SCHEDULED:
-	ASSERT(is_internal_ordinary_ref(retval));
-	break;
-    case ERTS_PORT_OP_DONE:
-	ASSERT(is_not_internal_ref(retval));
-	break;
-    default:
-	ERTS_INTERNAL_ERROR("Unexpected erts_port_control() result");
-	retval = am_internal_error;
-	break;
+    else if (!term_to_Uint(BIF_ARG_2, &uint_op))
+	retval = am_badarg;
+    else if (uint_op > (Uint) UINT_MAX)
+	retval = am_badarg;
+    else {
+        unsigned int op = (unsigned int) uint_op;
+
+        switch (erts_port_control(BIF_P, prt, op, BIF_ARG_3, &retval)) {
+        case ERTS_PORT_OP_BADARG:
+        case ERTS_PORT_OP_DROPPED:
+            retval = am_badarg;
+            break;
+        case ERTS_PORT_OP_SCHEDULED:
+            ASSERT(is_internal_ordinary_ref(retval));
+            /* Signal order preserved by reply... */
+            BIF_RET(retval);
+        case ERTS_PORT_OP_DONE:
+            ASSERT(is_not_internal_ref(retval));
+            break;
+        default:
+            ERTS_INTERNAL_ERROR("Unexpected erts_port_control() result");
+            retval = am_internal_error;
+            break;
+        }
     }
 
     state = erts_atomic32_read_acqb(&BIF_P->state);
     if (state & ERTS_PSFLG_EXITING)
 	ERTS_BIF_EXITED(BIF_P);
+    else {
+        /* Ensure signal order is preserved... */
+        if (state & (ERTS_PSFLG_SIG_Q|ERTS_PSFLG_SIG_IN_Q))
+            ERTS_BIF_HANDLE_SIGNALS_RETURN(BIF_P, retval);
+    }
 
     BIF_RET(retval);
 }
@@ -331,30 +348,44 @@ BIF_RETTYPE erts_internal_port_control_3(BIF_ALIST_3)
  */
 BIF_RETTYPE erts_internal_port_close_1(BIF_ALIST_1)
 {
-    Eterm ref;
+    Eterm retval;
     Port *prt;
 
+    prt = sig_lookup_port(BIF_P, BIF_ARG_1);
+    if (!prt)
+	retval = am_badarg;
+    else {
+
 #ifdef DEBUG
-    ref = NIL;
+        retval = NIL;
 #endif
 
-    prt = sig_lookup_port(BIF_P, BIF_ARG_1);
-    if (!prt)
-	BIF_RET(am_badarg);
-
-    switch (erts_port_exit(BIF_P, 0, prt, BIF_P->common.id, am_normal, &ref)) {
-    case ERTS_PORT_OP_BADARG:
-    case ERTS_PORT_OP_DROPPED:
-	BIF_RET(am_badarg);
-    case ERTS_PORT_OP_SCHEDULED:
-	ASSERT(is_internal_ordinary_ref(ref));
-	BIF_RET(ref);
-    case ERTS_PORT_OP_DONE:
-	BIF_RET(am_true);
-    default:
-	ERTS_INTERNAL_ERROR("Unexpected erts_port_exit() result");
-	BIF_RET(am_internal_error);
+        switch (erts_port_exit(BIF_P, 0, prt, BIF_P->common.id,
+                               am_normal, &retval)) {
+        case ERTS_PORT_OP_BADARG:
+        case ERTS_PORT_OP_DROPPED:
+            retval = am_badarg;
+            break;
+        case ERTS_PORT_OP_SCHEDULED:
+            ASSERT(is_internal_ordinary_ref(retval));
+            /* Signal order preserved by reply... */
+            BIF_RET(retval);
+            break;
+        case ERTS_PORT_OP_DONE:
+            retval = am_true;
+            break;
+        default:
+            ERTS_INTERNAL_ERROR("Unexpected erts_port_exit() result");
+            retval = am_internal_error;
+            break;
+        }
     }
+
+    /* Ensure signal order is preserved... */
+    if (ERTS_PROC_HAS_INCOMING_SIGNALS(BIF_P))
+        ERTS_BIF_HANDLE_SIGNALS_RETURN(BIF_P, retval);
+    
+    BIF_RET(retval);
 }
 
 /*
@@ -363,32 +394,42 @@ BIF_RETTYPE erts_internal_port_close_1(BIF_ALIST_1)
  */
 BIF_RETTYPE erts_internal_port_connect_2(BIF_ALIST_2)
 {
-    Eterm ref;
+    Eterm retval;
     Port* prt;
 
     prt = sig_lookup_port(BIF_P, BIF_ARG_1);
     if (!prt)
-	BIF_RET(am_badarg);
-
+	retval = am_badarg;
+    else {
 #ifdef DEBUG
-    ref = NIL;
+        retval = NIL;
 #endif
 
-    switch (erts_port_connect(BIF_P, 0, prt, BIF_P->common.id, BIF_ARG_2, &ref)) {
-    case ERTS_PORT_OP_BADARG:
-    case ERTS_PORT_OP_DROPPED:
-	BIF_RET(am_badarg);
-    case ERTS_PORT_OP_SCHEDULED:
-	ASSERT(is_internal_ordinary_ref(ref));
-	BIF_RET(ref);
-	break;
-    case ERTS_PORT_OP_DONE:
-	BIF_RET(am_true);
-	break;
-    default:
-	ERTS_INTERNAL_ERROR("Unexpected erts_port_connect() result");
-	BIF_RET(am_internal_error);
+        switch (erts_port_connect(BIF_P, 0, prt, BIF_P->common.id,
+                                  BIF_ARG_2, &retval)) {
+        case ERTS_PORT_OP_BADARG:
+        case ERTS_PORT_OP_DROPPED:
+            retval = am_badarg;
+            break;
+        case ERTS_PORT_OP_SCHEDULED:
+            ASSERT(is_internal_ordinary_ref(retval));
+            /* Signal order preserved by reply... */
+            BIF_RET(retval);
+        case ERTS_PORT_OP_DONE:
+            retval = am_true;
+            break;
+        default:
+            ERTS_INTERNAL_ERROR("Unexpected erts_port_connect() result");
+            retval = am_internal_error;
+            break;
+        }
     }
+
+    /* Ensure signal order is preserved... */
+    if (ERTS_PROC_HAS_INCOMING_SIGNALS(BIF_P))
+        ERTS_BIF_HANDLE_SIGNALS_RETURN(BIF_P, retval);
+    
+    BIF_RET(retval);
 }
 
 BIF_RETTYPE erts_internal_port_info_1(BIF_ALIST_1)
@@ -399,33 +440,44 @@ BIF_RETTYPE erts_internal_port_info_1(BIF_ALIST_1)
     if (is_internal_port(BIF_ARG_1) || is_atom(BIF_ARG_1)) {
 	prt = sig_lookup_port(BIF_P, BIF_ARG_1);
 	if (!prt)
-	    BIF_RET(am_undefined);
+	    retval = am_undefined;
+        else {
+            switch (erts_port_info(BIF_P, prt, THE_NON_VALUE, &retval)) {
+            case ERTS_PORT_OP_BADARG:
+                retval = am_badarg;
+                break;
+            case ERTS_PORT_OP_DROPPED:
+                retval = am_undefined;
+                break;
+            case ERTS_PORT_OP_SCHEDULED:
+                ASSERT(is_internal_ordinary_ref(retval));
+                /* Signal order preserved by reply... */
+                BIF_RET(retval);
+            case ERTS_PORT_OP_DONE:
+                ASSERT(is_not_internal_ref(retval));
+                break;
+            default:
+                ERTS_INTERNAL_ERROR("Unexpected erts_port_info() result");
+                retval = am_internal_error;
+                break;
+            }
+        }
     }
     else if (is_external_port(BIF_ARG_1)) {
 	if (external_port_dist_entry(BIF_ARG_1) == erts_this_dist_entry)
-	    BIF_RET(am_undefined);
+	    retval = am_undefined;
 	else
-	    BIF_RET(am_badarg);
+	    retval = am_badarg;
     }
     else {
-	BIF_RET(am_badarg);
-    }
-
-    switch (erts_port_info(BIF_P, prt, THE_NON_VALUE, &retval)) {
-    case ERTS_PORT_OP_BADARG:
-	BIF_RET(am_badarg);
-    case ERTS_PORT_OP_DROPPED:
-	BIF_RET(am_undefined);
-    case ERTS_PORT_OP_SCHEDULED:
-	ASSERT(is_internal_ordinary_ref(retval));
-	BIF_RET(retval);
-    case ERTS_PORT_OP_DONE:
-	ASSERT(is_not_internal_ref(retval));
-	BIF_RET(retval);
-    default:
-	ERTS_INTERNAL_ERROR("Unexpected erts_port_info() result");
-	BIF_RET(am_internal_error);
+	retval = am_badarg;
     }
+
+    /* Ensure signal order is preserved... */
+    if (ERTS_PROC_HAS_INCOMING_SIGNALS(BIF_P))
+        ERTS_BIF_HANDLE_SIGNALS_RETURN(BIF_P, retval);
+    
+    BIF_RET(retval);
 }
 
 
@@ -437,33 +489,44 @@ BIF_RETTYPE erts_internal_port_info_2(BIF_ALIST_2)
     if (is_internal_port(BIF_ARG_1) || is_atom(BIF_ARG_1)) {
 	prt = sig_lookup_port(BIF_P, BIF_ARG_1);
 	if (!prt)
-	    BIF_RET(am_undefined);
+	    retval = am_undefined;
+        else {
+            switch (erts_port_info(BIF_P, prt, BIF_ARG_2, &retval)) {
+            case ERTS_PORT_OP_BADARG:
+                retval = am_badarg;
+                break;
+            case ERTS_PORT_OP_DROPPED:
+                retval = am_undefined;
+                break;
+            case ERTS_PORT_OP_SCHEDULED:
+                ASSERT(is_internal_ordinary_ref(retval));
+                /* Signal order preserved by reply... */
+                BIF_RET(retval);
+            case ERTS_PORT_OP_DONE:
+                ASSERT(is_not_internal_ref(retval));
+                break;
+            default:
+                ERTS_INTERNAL_ERROR("Unexpected erts_port_info() result");
+                retval = am_internal_error;
+                break;
+            }
+        }
     }
     else if (is_external_port(BIF_ARG_1)) {
 	if (external_port_dist_entry(BIF_ARG_1) == erts_this_dist_entry)
-	    BIF_RET(am_undefined);
+	    retval = am_undefined;
 	else
-	    BIF_RET(am_badarg);
+	    retval = am_badarg;
     }
     else {
-	BIF_RET(am_badarg);
-    }
-
-    switch (erts_port_info(BIF_P, prt, BIF_ARG_2, &retval)) {
-    case ERTS_PORT_OP_BADARG:
-	BIF_RET(am_badarg);
-    case ERTS_PORT_OP_DROPPED:
-	BIF_RET(am_undefined);
-    case ERTS_PORT_OP_SCHEDULED:
-	ASSERT(is_internal_ordinary_ref(retval));
-	BIF_RET(retval);
-    case ERTS_PORT_OP_DONE:
-	ASSERT(is_not_internal_ref(retval));
-	BIF_RET(retval);
-    default:
-	ERTS_INTERNAL_ERROR("Unexpected erts_port_info() result");
-	BIF_RET(am_internal_error);
+	retval = am_badarg;
     }
+
+    /* Ensure signal order is preserved... */
+    if (ERTS_PROC_HAS_INCOMING_SIGNALS(BIF_P))
+        ERTS_BIF_HANDLE_SIGNALS_RETURN(BIF_P, retval);
+
+    BIF_RET(retval);
 }
 
 /*