diff --git a/lldb/source/Target/ThreadPlanCallFunction.cpp b/lldb/source/Target/ThreadPlanCallFunction.cpp
--- a/lldb/source/Target/ThreadPlanCallFunction.cpp
+++ b/lldb/source/Target/ThreadPlanCallFunction.cpp
@@ -267,6 +267,12 @@
   if (stop_reason == eStopReasonBreakpoint && BreakpointsExplainStop())
     return true;
 
+  if (stop_reason == eStopReasonFork || stop_reason == eStopReasonVFork ||
+      stop_reason == eStopReasonVForkDone) {
+    LLDB_LOGF(log, "ThreadPlanCallFunction::PlanExplainsStop not done for fork stop reasons.");
+    return false;
+  }
+
   // One more quirk here.  If this event was from Halt interrupting the target,
   // then we should not consider ourselves complete.  Return true to
   // acknowledge the stop.
@@ -371,7 +377,7 @@
 
 #ifndef SINGLE_STEP_EXPRESSIONS
   Thread &thread = GetThread();
-  m_subplan_sp = std::make_shared<ThreadPlanRunToAddress>(thread, m_start_addr, 
+  m_subplan_sp = std::make_shared<ThreadPlanRunToAddress>(thread, m_start_addr,
                                                           m_stop_other_threads);
 
   thread.QueueThreadPlan(m_subplan_sp, false);
diff --git a/lldb/test/API/commands/expression/fork/Makefile b/lldb/test/API/commands/expression/fork/Makefile
new file mode 100644
--- /dev/null
+++ b/lldb/test/API/commands/expression/fork/Makefile
@@ -0,0 +1,3 @@
+CXX_SOURCES := main.cpp
+
+include Makefile.rules
diff --git a/lldb/test/API/commands/expression/fork/TestForkExprs.py b/lldb/test/API/commands/expression/fork/TestForkExprs.py
new file mode 100644
--- /dev/null
+++ b/lldb/test/API/commands/expression/fork/TestForkExprs.py
@@ -0,0 +1,41 @@
+"""
+Test some more expression commands.
+"""
+
+
+
+import lldb
+from lldbsuite.test.decorators import *
+from lldbsuite.test.lldbtest import *
+from lldbsuite.test import lldbutil
+
+
+class ExprCommandsForkExpressions(TestBase):
+
+    NO_DEBUG_INFO_TESTCASE = True
+
+    def setUp(self):
+        # Call super's setUp().
+        TestBase.setUp(self)
+
+    @skipUnlessPlatform(["linux"])
+    def test_more_expr_commands(self):
+        """Test some more expression commands."""
+        self.build()
+
+        (target, process, self.thread, bkpt) = lldbutil.run_to_source_breakpoint(self,
+                                        'Stop here to evaluate expressions',
+                                         lldb.SBFileSpec("main.cpp"))
+
+        self.assertTrue(bkpt.IsValid())
+        bkpt.SetEnabled(False)
+        options = lldb.SBExpressionOptions()
+        options.SetIgnoreBreakpoints(True)
+        frame = self.thread.GetFrameAtIndex(0)
+
+        value = frame.EvaluateExpression("do_fork(argv, envp)", options)
+        self.assertTrue(value.IsValid())
+        self.assertSuccess(value.GetError())
+        value = frame.EvaluateExpression("do_vfork(argv, envp)", options)
+        self.assertTrue(value.IsValid())
+        self.assertSuccess(value.GetError())
diff --git a/lldb/test/API/commands/expression/fork/main.cpp b/lldb/test/API/commands/expression/fork/main.cpp
new file mode 100644
--- /dev/null
+++ b/lldb/test/API/commands/expression/fork/main.cpp
@@ -0,0 +1,29 @@
+#include <sys/types.h>
+#include <unistd.h>
+
+pid_t do_fork(char *const argv[], char *const envp[]) {
+  pid_t pid = fork();
+  if (pid == 0)
+    execve(argv[0], argv, envp);
+  return pid;
+}
+
+pid_t do_vfork(char *const argv[], char *const envp[]) {
+  pid_t pid = vfork();
+  if (pid == 0)
+    execve(argv[0], argv, envp);
+  return pid;
+}
+
+int main(int argc, char *const argv[], char *const envp[]) {
+  // Stop here to evaluate expressions
+  // Optionally call do_fork() when argc is 4 to make sure do_fork() doesn't get
+  // dead stripped
+  if (argc == 4)
+    do_fork(argv, envp);
+  // Optionally call do_vfork() when argc is 5 to make sure do_fork() doesn't
+  // get dead stripped
+  if (argc == 5)
+    do_vfork(argv, envp);
+  return 0;
+}