diff --git a/common/crypto_sync.c b/common/crypto_sync.c
index 878ff0628..633474bc5 100644
--- a/common/crypto_sync.c
+++ b/common/crypto_sync.c
@@ -25,6 +25,9 @@ bool sync_crypto_write(struct crypto_state *cs, int fd, const void *msg TAKES)
 	case DEV_DISCONNECT_AFTER:
 		post_sabotage = true;
 		break;
+	case DEV_DISCONNECT_BLACKHOLE:
+		dev_blackhole_fd(fd);
+		break;
 	default:
 		break;
 	}
diff --git a/common/cryptomsg.c b/common/cryptomsg.c
index aeed15c35..db4288c9e 100644
--- a/common/cryptomsg.c
+++ b/common/cryptomsg.c
@@ -352,6 +352,9 @@ struct io_plan *peer_write_message(struct io_conn *conn,
 	case DEV_DISCONNECT_AFTER:
 		post = peer_write_postclose;
 		break;
+	case DEV_DISCONNECT_BLACKHOLE:
+		dev_blackhole_fd(io_conn_fd(conn));
+		break;
 	default:
 		break;
 	}
diff --git a/common/dev_disconnect.c b/common/dev_disconnect.c
index b1fd99369..e7d9cec50 100644
--- a/common/dev_disconnect.c
+++ b/common/dev_disconnect.c
@@ -3,8 +3,10 @@
 #include <ccan/str/str.h>
 #include <common/dev_disconnect.h>
 #include <common/status.h>
+#include <fcntl.h>
 #include <stdlib.h>
 #include <sys/socket.h>
+#include <sys/stat.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <wire/gen_peer_wire.h>
@@ -64,7 +66,7 @@ void dev_sabotage_fd(int fd)
 	int fds[2];
 
 	if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) != 0)
-		errx(1, "dev_sabotage_fd: creating socketpair");
+		err(1, "dev_sabotage_fd: creating socketpair");
 
 	/* Close one. */
 	close(fds[0]);
@@ -72,3 +74,40 @@ void dev_sabotage_fd(int fd)
 	dup2(fds[1], fd);
 	close(fds[1]);
 }
+
+/* Replace fd with blackhole until dev_disconnect file is truncated. */
+void dev_blackhole_fd(int fd)
+{
+	int fds[2];
+	int i;
+	struct stat st;
+
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, fds) != 0)
+		err(1, "dev_blackhole_fd: creating socketpair");
+
+	switch (fork()) {
+	case -1:
+		err(1, "dev_blackhole_fd: forking");
+	case 0:
+		/* Close everything but the dev_disconnect_fd, the socket
+		 * which is pretending to be the peer, and stderr. */
+		for (i = 0; i < sysconf(_SC_OPEN_MAX); i++)
+			if (i != fds[0]
+			    && i != dev_disconnect_fd
+			    && i != STDERR_FILENO)
+				close(i);
+
+		/* Close once dev_disconnect file is truncated. */
+		for (;;) {
+			if (fstat(dev_disconnect_fd, &st) != 0)
+				err(1, "fstat of dev_disconnect_fd failed");
+			if (st.st_size == 0)
+				_exit(0);
+			sleep(1);
+		}
+	}
+
+	close(fds[0]);
+	dup2(fds[1], fd);
+	close(fds[1]);
+}
diff --git a/common/dev_disconnect.h b/common/dev_disconnect.h
index efa83a5d5..108b9c92f 100644
--- a/common/dev_disconnect.h
+++ b/common/dev_disconnect.h
@@ -6,6 +6,7 @@
 #define DEV_DISCONNECT_BEFORE '-'
 #define DEV_DISCONNECT_AFTER '+'
 #define DEV_DISCONNECT_DROPPKT '@'
+#define DEV_DISCONNECT_BLACKHOLE '0'
 #define DEV_DISCONNECT_NORMAL 0
 
 /* Force a close fd before or after a certain packet type */
@@ -14,6 +15,9 @@ char dev_disconnect(int pkt_type);
 /* Make next write on fd fail as if they'd disconnected. */
 void dev_sabotage_fd(int fd);
 
+/* No more data to arrive, what's written is swallowed. */
+void dev_blackhole_fd(int fd);
+
 /* For debug code to set in daemon. */
 void dev_disconnect_init(int fd);
 
diff --git a/lightningd/peer_control.c b/lightningd/peer_control.c
index c6084a08d..ecb0f1bed 100644
--- a/lightningd/peer_control.c
+++ b/lightningd/peer_control.c
@@ -263,6 +263,11 @@ void dev_sabotage_fd(int fd)
 	abort();
 }
 
+void dev_blackhole_fd(int fd)
+{
+	abort();
+}
+
 /* Send (encrypted) error message, then close. */
 static struct io_plan *send_error(struct io_conn *conn,
 				  struct peer_crypto_state *pcs)
diff --git a/lightningd/test/run-cryptomsg.c b/lightningd/test/run-cryptomsg.c
index 76466552c..1f0b4f57c 100644
--- a/lightningd/test/run-cryptomsg.c
+++ b/lightningd/test/run-cryptomsg.c
@@ -39,10 +39,14 @@ static void do_write(const void *buf, size_t len)
 #define status_trace(fmt, ...) \
 	printf(fmt "\n", __VA_ARGS__)
 
-void dev_sabotage_fd(int fd)
-{
-	abort();
-}
+/* AUTOGENERATED MOCKS START */
+/* Generated stub for dev_blackhole_fd */
+void dev_blackhole_fd(int fd UNNEEDED)
+{ fprintf(stderr, "dev_blackhole_fd called!\n"); abort(); }
+/* Generated stub for dev_sabotage_fd */
+void dev_sabotage_fd(int fd UNNEEDED)
+{ fprintf(stderr, "dev_sabotage_fd called!\n"); abort(); }
+/* AUTOGENERATED MOCKS END */
 
 char dev_disconnect(int pkt_type)
 {
diff --git a/tests/utils.py b/tests/utils.py
index ecb9e9ac8..776009c83 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -59,15 +59,15 @@ class TailableProc(object):
         self.running = True
 
     def stop(self):
-        self.proc.terminate()
-        self.proc.kill()
-        self.proc.wait()
-        self.thread.join()
         if self.outputDir:
             logpath = os.path.join(self.outputDir, 'log')
             with open(logpath, 'w') as f:
                 for l in self.logs:
                     f.write(l + '\n')
+        self.proc.terminate()
+        self.proc.kill()
+        self.proc.wait()
+        self.thread.join()
 
     def tail(self):
         """Tail the stdout of the process and remember it.