From 3671dd2d426208cf0639530b294da083b5e75acd Mon Sep 17 00:00:00 2001
From: Lukas Larsson <lukas@erlang.org>
Date: Tue, 21 Feb 2017 09:52:51 +0100
Subject: erts: Emasculate binaries that are scheduled in port_control

---
 erts/emulator/beam/io.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/erts/emulator/beam/io.c b/erts/emulator/beam/io.c
index 31396d06c6..9bf29ee230 100644
--- a/erts/emulator/beam/io.c
+++ b/erts/emulator/beam/io.c
@@ -4884,10 +4884,16 @@ erts_port_control(Process* c_p,
 	ASSERT(!tmp_alloced);
 	if (*ebinp == HEADER_SUB_BIN)
 	    ebinp = binary_val(((ErlSubBin *) ebinp)->orig);
+
 	if (*ebinp != HEADER_PROC_BIN)
 	    copy = 1;
 	else {
-	    binp = ((ProcBin *) ebinp)->val;
+            ProcBin *pb = (ProcBin *) ebinp;
+
+            if (pb->flags)
+                erts_emasculate_writable_binary(pb);
+
+	    binp = pb->val;
 	    ASSERT(bufp <= bufp + size);
 	    ASSERT(binp->orig_bytes <= bufp
 		   && bufp + size <= binp->orig_bytes + binp->orig_size);
-- 
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