From c5287237ee9df53e754cbd7b10555d45ca5cc3b8 Mon Sep 17 00:00:00 2001
From: Leonardo de Moura <leonardo@microsoft.com>
Date: Wed, 15 Feb 2017 15:35:41 -0800
Subject: [PATCH] fix(library/vm): race condition in the profiler
 initialization code

---
 src/library/vm/vm.cpp | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/library/vm/vm.cpp b/src/library/vm/vm.cpp
index b2347f6a7c..b043013495 100644
--- a/src/library/vm/vm.cpp
+++ b/src/library/vm/vm.cpp
@@ -3290,8 +3290,6 @@ vm_state::profiler::profiler(vm_state & s, options const & opts):
     m_freq_ms(get_profiler_freq(opts)),
     m_thread_ptr(get_profiler(opts) ?
         new interruptible_thread([&]() {
-                lean_assert(!m_state.m_profiling);
-                m_state.m_profiling = true;
                 chrono::milliseconds d(m_freq_ms);
                 bool first = true;
                 auto start = chrono::steady_clock::now();
@@ -3320,7 +3318,8 @@ vm_state::profiler::profiler(vm_state & s, options const & opts):
     m_freq_ms(0),
     m_thread_ptr(nullptr)
 #endif
-        {
+{
+    m_state.m_profiling = get_profiler(opts);
 }
 
 void vm_state::profiler::stop() {