From b9c426012770d166e6ebfab27689be44e6e89aa5 Mon Sep 17 00:00:00 2001 From: Anthony Towns Date: Sun, 1 Mar 2020 14:22:37 +1000 Subject: sync.h: add REVERSE_LOCK --- src/sync.cpp | 19 +++++++++++++++++- src/sync.h | 39 ++++++++++++++++++++++++++++++++++++ src/test/reverselock_tests.cpp | 45 ++++++++++++++++++++++++++++++++++-------- 3 files changed, 94 insertions(+), 9 deletions(-) (limited to 'src') diff --git a/src/sync.cpp b/src/sync.cpp index 924e7b5bb0..71657a7439 100644 --- a/src/sync.cpp +++ b/src/sync.cpp @@ -13,7 +13,7 @@ #include #include - +#include #include #include @@ -60,6 +60,11 @@ struct CLockLocation { mutexName, sourceFile, itostr(sourceLine), (fTry ? " (TRY)" : ""), m_thread_name); } + std::string Name() const + { + return mutexName; + } + private: bool fTry; std::string mutexName; @@ -155,6 +160,18 @@ void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs push_lock(cs, CLockLocation(pszName, pszFile, nLine, fTry, util::ThreadGetInternalName())); } +void CheckLastCritical(void* cs, std::string& lockname, const char* guardname, const char* file, int line) +{ + if (!g_lockstack.empty()) { + const auto& lastlock = g_lockstack.back(); + if (lastlock.first == cs) { + lockname = lastlock.second.Name(); + return; + } + } + throw std::system_error(EPERM, std::generic_category(), strprintf("%s:%s %s was not most recent critical section locked", file, line, guardname)); +} + void LeaveCritical() { pop_lock(); diff --git a/src/sync.h b/src/sync.h index 0cdbb59c70..204734c273 100644 --- a/src/sync.h +++ b/src/sync.h @@ -50,6 +50,7 @@ LEAVE_CRITICAL_SECTION(mutex); // no RAII #ifdef DEBUG_LOCKORDER void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry = false); void LeaveCritical(); +void CheckLastCritical(void* cs, std::string& lockname, const char* guardname, const char* file, int line); std::string LocksHeld(); void AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs) ASSERT_EXCLUSIVE_LOCK(cs); void AssertLockNotHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs); @@ -64,6 +65,7 @@ extern bool g_debug_lockorder_abort; #else void static inline EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry = false) {} void static inline LeaveCritical() {} +void static inline CheckLastCritical(void* cs, std::string& lockname, const char* guardname, const char* file, int line) {} void static inline AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs) ASSERT_EXCLUSIVE_LOCK(cs) {} void static inline AssertLockNotHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs) {} void static inline DeleteLock(void* cs) {} @@ -171,8 +173,45 @@ public: { return Base::owns_lock(); } + +protected: + // needed for reverse_lock + UniqueLock() { } + +public: + /** + * An RAII-style reverse lock. Unlocks on construction and locks on destruction. + */ + class reverse_lock { + public: + explicit reverse_lock(UniqueLock& _lock, const char* _guardname, const char* _file, int _line) : lock(_lock), file(_file), line(_line) { + CheckLastCritical((void*)lock.mutex(), lockname, _guardname, _file, _line); + lock.unlock(); + LeaveCritical(); + lock.swap(templock); + } + + ~reverse_lock() { + templock.swap(lock); + EnterCritical(lockname.c_str(), file.c_str(), line, (void*)lock.mutex()); + lock.lock(); + } + + private: + reverse_lock(reverse_lock const&); + reverse_lock& operator=(reverse_lock const&); + + UniqueLock& lock; + UniqueLock templock; + std::string lockname; + const std::string file; + const int line; + }; + friend class reverse_lock; }; +#define REVERSE_LOCK(g) decltype(g)::reverse_lock PASTE2(revlock, __COUNTER__)(g, #g, __FILE__, __LINE__) + template using DebugLock = UniqueLock::type>::type>; diff --git a/src/test/reverselock_tests.cpp b/src/test/reverselock_tests.cpp index 532fe143ae..4e51b8c02a 100644 --- a/src/test/reverselock_tests.cpp +++ b/src/test/reverselock_tests.cpp @@ -2,7 +2,7 @@ // Distributed under the MIT software license, see the accompanying // file COPYING or http://www.opensource.org/licenses/mit-license.php. -#include +#include #include #include @@ -11,21 +11,50 @@ BOOST_FIXTURE_TEST_SUITE(reverselock_tests, BasicTestingSetup) BOOST_AUTO_TEST_CASE(reverselock_basics) { - boost::mutex mutex; - boost::unique_lock lock(mutex); + Mutex mutex; + WAIT_LOCK(mutex, lock); BOOST_CHECK(lock.owns_lock()); { - reverse_lock > rlock(lock); + REVERSE_LOCK(lock); BOOST_CHECK(!lock.owns_lock()); } BOOST_CHECK(lock.owns_lock()); } +BOOST_AUTO_TEST_CASE(reverselock_multiple) +{ + Mutex mutex2; + Mutex mutex; + WAIT_LOCK(mutex2, lock2); + WAIT_LOCK(mutex, lock); + + // Make sure undoing two locks succeeds + { + REVERSE_LOCK(lock); + BOOST_CHECK(!lock.owns_lock()); + REVERSE_LOCK(lock2); + BOOST_CHECK(!lock2.owns_lock()); + } + BOOST_CHECK(lock.owns_lock()); + BOOST_CHECK(lock2.owns_lock()); +} + BOOST_AUTO_TEST_CASE(reverselock_errors) { - boost::mutex mutex; - boost::unique_lock lock(mutex); + Mutex mutex2; + Mutex mutex; + WAIT_LOCK(mutex2, lock2); + WAIT_LOCK(mutex, lock); + +#ifdef DEBUG_LOCKORDER + // Make sure trying to reverse lock a previous lock fails + try { + REVERSE_LOCK(lock2); + BOOST_CHECK(false); // REVERSE_LOCK(lock2) succeeded + } catch(...) { } + BOOST_CHECK(lock2.owns_lock()); +#endif // Make sure trying to reverse lock an unlocked lock fails lock.unlock(); @@ -34,7 +63,7 @@ BOOST_AUTO_TEST_CASE(reverselock_errors) bool failed = false; try { - reverse_lock > rlock(lock); + REVERSE_LOCK(lock); } catch(...) { failed = true; } @@ -49,7 +78,7 @@ BOOST_AUTO_TEST_CASE(reverselock_errors) lock.lock(); BOOST_CHECK(lock.owns_lock()); { - reverse_lock > rlock(lock); + REVERSE_LOCK(lock); BOOST_CHECK(!lock.owns_lock()); } -- cgit v1.2.3