diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 1c98bbd031..6d1f5f7af5 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,12 @@
+2018-06-14  Pedro Alves  <palves@redhat.com>
+
+	* gdb.base/fork-running-state.c: Include <errno.h>.
+	(exit_if_relative_exits): New.
+	(fork_child): If 'exit_if_relative_exits' is true, exit if the parent
+	exits.
+	(fork_parent): If 'exit_if_relative_exits' is true, exit if the
+	child exits.
+
 2018-06-14  Tom de Vries  <tdevries@suse.de>
 
 	PR cli/22573
diff --git a/gdb/testsuite/gdb.base/fork-running-state.c b/gdb/testsuite/gdb.base/fork-running-state.c
index 65ca942ea0..0037cb5a5e 100644
--- a/gdb/testsuite/gdb.base/fork-running-state.c
+++ b/gdb/testsuite/gdb.base/fork-running-state.c
@@ -19,9 +19,15 @@
 #include <stdio.h>
 #include <sys/types.h>
 #include <sys/wait.h>
+#include <errno.h>
 
 int save_parent;
 
+/* Variable set by GDB.  If true, then a fork child (or parent) exits
+   if its parent (or child) exits.  Otherwise the process waits
+   forever until either GDB or the alarm kills it.  */
+volatile int exit_if_relative_exits = 0;
+
 /* The fork child.  Just runs forever.  */
 
 static int
@@ -31,7 +37,20 @@ fork_child (void)
   alarm (180);
 
   while (1)
-    pause ();
+    {
+      if (exit_if_relative_exits)
+	{
+	  sleep (1);
+
+	  /* Exit if GDB kills the parent.  */
+	  if (getppid () != save_parent)
+	    break;
+	  if (kill (getppid (), 0) != 0)
+	    break;
+	}
+      else
+	pause ();
+    }
 
   return 0;
 }
@@ -45,7 +64,23 @@ fork_parent (void)
   alarm (180);
 
   while (1)
-    pause ();
+    {
+      if (exit_if_relative_exits)
+	{
+	  int res = wait (NULL);
+	  if (res == -1 && errno == EINTR)
+	    continue;
+	  else if (res == -1)
+	    {
+	      perror ("wait");
+	      return 1;
+	    }
+	  else
+	    return 0;
+	}
+      else
+	pause ();
+    }
 
   return 0;
 }
diff --git a/gdb/testsuite/gdb.base/fork-running-state.exp b/gdb/testsuite/gdb.base/fork-running-state.exp
index 27ed8a43e9..c15bc53f7a 100644
--- a/gdb/testsuite/gdb.base/fork-running-state.exp
+++ b/gdb/testsuite/gdb.base/fork-running-state.exp
@@ -70,6 +70,13 @@ proc do_test { detach_on_fork follow_fork non_stop schedule_multiple } {
 	gdb_test_no_output "set schedule-multiple $schedule_multiple"
     }
 
+    # If we're detaching from the parent (or child), then tell it to
+    # exit itself when its child (or parent) exits.  If we stay
+    # attached, we take care of killing it.
+    if {$detach_on_fork == "on"} {
+	gdb_test "print exit_if_relative_exits = 1" " = 1"
+    }
+
     set test "continue &"
     gdb_test_multiple $test $test {
 	-re "$gdb_prompt " {