a.patch

diff --git a/runtime/linux/task_finder.c b/runtime/linux/task_finder.c
index 1358e36c2..62a872624 100644
--- a/runtime/linux/task_finder.c
+++ b/runtime/linux/task_finder.c
@@ -1412,11 +1412,10 @@ __stp_utrace_task_finder_target_quiesce(enum utrace_resume_action action,
 		_stp_error("utrace_set_events returned error %d on pid %d",
 			   rc, (int)tsk->pid);
 
+	/* NB make sure we run mmap callbacks before other callbacks
+	 * like 'probe process.begin' handlers so that the vma tracker
+	 * is already initialized in the latter contexts */
 
-	/* Call the callbacks.  Assume that if the thread is a
-	 * thread group leader, it is a process. */
-	__stp_call_callbacks(tgt, tsk, 1, (tsk->pid == tsk->tgid));
- 
 	/* If this is just a thread other than the thread group leader,
            don't bother inform map callback clients about its memory map,
            since they will simply duplicate each other. */
@@ -1424,6 +1423,10 @@ __stp_utrace_task_finder_target_quiesce(enum utrace_resume_action action,
 		__stp_call_mmap_callbacks_for_task(tgt, tsk);
 	}
 
+	/* Call the callbacks.  Assume that if the thread is a
+	 * thread group leader, it is a process. */
+	__stp_call_callbacks(tgt, tsk, 1, (tsk->pid == tsk->tgid));
+
 	__stp_tf_handler_end();
 	return UTRACE_RESUME;
 }
diff --git a/runtime/linux/task_finder2.c b/runtime/linux/task_finder2.c
index 4fd0dfe56..c0dea2ac2 100644
--- a/runtime/linux/task_finder2.c
+++ b/runtime/linux/task_finder2.c
@@ -1429,10 +1429,10 @@ __stp_utrace_task_finder_target_quiesce(u32 action,
 		}
 	}
 	else {
-		/* Call the callbacks.  Assume that if the thread is a
-		 * thread group leader, it is a process. */
-		__stp_call_callbacks(tgt, tsk, 1, (tsk->pid == tsk->tgid));
- 
+		/* NB make sure we run mmap callbacks before other callbacks
+		 * like 'probe process.begin' handlers so that the vma tracker
+		 * is already initialized in the latter contexts */
+
 		/* If this is just a thread other than the thread
 		   group leader, don't bother inform map callback
 		   clients about its memory map, since they will
@@ -1440,6 +1440,10 @@ __stp_utrace_task_finder_target_quiesce(u32 action,
 		if (tgt->mmap_events == 1 && tsk->tgid == tsk->pid) {
 			__stp_call_mmap_callbacks_for_task(tgt, tsk);
 		}
+
+		/* Call the callbacks.  Assume that if the thread is a
+		 * thread group leader, it is a process. */
+		__stp_call_callbacks(tgt, tsk, 1, (tsk->pid == tsk->tgid));
 	}
 
 	__stp_tf_handler_end();
diff --git a/testsuite/systemtap.base/process-begin-user.exp b/testsuite/systemtap.base/process-begin-user.exp
index 66c9e8b0e..6cd701ba8 100644
--- a/testsuite/systemtap.base/process-begin-user.exp
+++ b/testsuite/systemtap.base/process-begin-user.exp
@@ -39,6 +39,9 @@ if {$res ne ""} {
 
 set subtest2 "TEST 2: register() in probe process.end"
 
+# NB This test case is expected to fail on CentOS 6 on which registers are
+# actually usable in the prcoess.end probe.
+
 set res [target_compile ${testpath}/${test}_1.c ./a.out executable \
     "additional_flags=-O additional_flags=-g"]
 if {$res ne ""} {
@@ -67,7 +70,7 @@ if {$res ne ""} {
 
 # --- TEST 3 ---
 
-set subtest3 "TEST 3: @var() in probe process.begin (with vma tracker)"
+set subtest3 "TEST 3: @var() in probe process(PATH).begin (with vma tracker)"
 
 set res [target_compile ${testpath}/${test}_3.c ./a.out executable \
     "additional_flags=-O additional_flags=-g additional_flags=-pie additional_flags=-fpic"]
@@ -95,3 +98,34 @@ if {$res ne ""} {
         }
     }
 }
+
+# --- TEST 4 ---
+
+set subtest4 "TEST 4: @var() in probe process.begin (with vma tracker)"
+
+set res [target_compile ${testpath}/${test}_3.c ./a.out executable \
+    "additional_flags=-O additional_flags=-g additional_flags=-pie additional_flags=-fpic"]
+if {$res ne ""} {
+    verbose "target_compile failed: $res" 2
+    fail "$test: $subtest4: unable to compile ${test}_3.c"
+} else {
+    if {! [process_template_file "$srcdir/$subdir/${test}_4.stp" \
+                                 "./${test}_4.stp" "./a.out" nm_err]} {
+        fail "$test: $subtest4: $nm_err"
+    } else {
+        foreach runtime [get_runtime_list] {
+            if {$runtime eq ""} {
+                set runtime "kernel"
+            }
+            set test_name "$test: $subtest4 ($runtime)"
+            set cmd "stap --runtime=$runtime -c ./a.out './${test}_4.stp'"
+            set exit_code [run_cmd_2way $cmd out stderr]
+            set exp_out "a: 32\n"
+            is "${test_name}: stdout" $out $exp_out
+            is "${test_name}: exit code" $exit_code 0
+            if {$stderr ne ""} {
+                send_log "stderr:\n$stderr"
+            }
+        }
+    }
+}
diff --git a/testsuite/systemtap.base/process-begin-user_4.stp b/testsuite/systemtap.base/process-begin-user_4.stp
new file mode 100644
index 000000000..45f85e386
--- /dev/null
+++ b/testsuite/systemtap.base/process-begin-user_4.stp
@@ -0,0 +1,5 @@
+probe process.begin {
+    if (&@var("a", "$^PWD/a.out") != 0) {
+        printf("a: %d\n", @var("a", "$^PWD/a.out"));
+    }
+}