From f119ef798b9d6d5bac78148472e783428f27447a Mon Sep 17 00:00:00 2001
From: ReinUsesLisp <reinuseslisp@airmail.cc>
Date: Wed, 26 Aug 2020 01:41:46 +0000
Subject: [PATCH] common/thread: Fix data race in is_set
As report by tsan, Event::Set can write is_set while WaitFor and friends
are reading from it. To address this issue, make is_set an atomic.
---
src/common/thread.h | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/src/common/thread.h b/src/common/thread.h
index 52b3594131..a8c17c71ab 100644
--- a/src/common/thread.h
+++ b/src/common/thread.h
@@ -4,6 +4,7 @@
#pragma once
+#include <atomic>
#include <chrono>
#include <condition_variable>
#include <cstddef>
@@ -25,13 +26,13 @@ public:
void Wait() {
std::unique_lock lk{mutex};
- condvar.wait(lk, [&] { return is_set; });
+ condvar.wait(lk, [&] { return is_set.load(); });
is_set = false;
}
bool WaitFor(const std::chrono::nanoseconds& time) {
std::unique_lock lk{mutex};
- if (!condvar.wait_for(lk, time, [this] { return is_set; }))
+ if (!condvar.wait_for(lk, time, [this] { return is_set.load(); }))
return false;
is_set = false;
return true;
@@ -40,7 +41,7 @@ public:
template <class Clock, class Duration>
bool WaitUntil(const std::chrono::time_point<Clock, Duration>& time) {
std::unique_lock lk{mutex};
- if (!condvar.wait_until(lk, time, [this] { return is_set; }))
+ if (!condvar.wait_until(lk, time, [this] { return is_set.load(); }))
return false;
is_set = false;
return true;
@@ -54,9 +55,9 @@ public:
}
private:
- bool is_set = false;
std::condition_variable condvar;
std::mutex mutex;
+ std::atomic_bool is_set{false};
};
class Barrier {