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authorGavin Andresen <gavinandresen@gmail.com>2011-03-29 11:32:16 -0400
committerGavin Andresen <gavinandresen@gmail.com>2011-08-17 10:22:28 -0400
commit865ed8a1e5c587468a40756d46bcbc1c5a12bb06 (patch)
tree178a78d9057931de2a0db1099193efe73da6d6a1 /src/util.cpp
parentc7286112efe5c9ee7924aa387c8f4280473a72a8 (diff)
Compile with DEBUG_LOCKORDER to detect inconsistent lock orderings that can cause deadlocks
Diffstat (limited to 'src/util.cpp')
-rw-r--r--src/util.cpp118
1 files changed, 118 insertions, 0 deletions
diff --git a/src/util.cpp b/src/util.cpp
index 1784448fc8..24c7ed4487 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -909,4 +909,122 @@ string FormatFullVersion()
+#ifdef DEBUG_LOCKORDER
+//
+// Early deadlock detection.
+// Problem being solved:
+// Thread 1 locks A, then B, then C
+// Thread 2 locks D, then C, then A
+// --> may result in deadlock between the two threads, depending on when they run.
+// Solution implemented here:
+// Keep track of pairs of locks: (A before B), (A before C), etc.
+// Complain if any thread trys to lock in a different order.
+//
+
+struct CLockLocation
+{
+ std::string mutexName;
+ std::string sourceFile;
+ int sourceLine;
+
+ CLockLocation(const char* pszName, const char* pszFile, int nLine)
+ {
+ mutexName = pszName;
+ sourceFile = pszFile;
+ sourceLine = nLine;
+ }
+};
+
+typedef std::vector< std::pair<CCriticalSection*, CLockLocation> > LockStack;
+
+static boost::interprocess::interprocess_mutex dd_mutex;
+static std::map<std::pair<CCriticalSection*, CCriticalSection*>, LockStack> lockorders;
+static boost::thread_specific_ptr<LockStack> lockstack;
+
+
+static void potential_deadlock_detected(const LockStack& s1, const LockStack& s2)
+{
+ printf("POTENTIAL DEADLOCK DETECTED\n");
+ printf("Previous lock order was:\n");
+ BOOST_FOREACH(const PAIRTYPE(CCriticalSection*, CLockLocation)& i, s2)
+ {
+ printf(" %s %s:%d\n", i.second.mutexName.c_str(), i.second.sourceFile.c_str(), i.second.sourceLine);
+ }
+ printf("Current lock order is:\n");
+ BOOST_FOREACH(const PAIRTYPE(CCriticalSection*, CLockLocation)& i, s1)
+ {
+ printf(" %s %s:%d\n", i.second.mutexName.c_str(), i.second.sourceFile.c_str(), i.second.sourceLine);
+ }
+}
+
+static void push_lock(CCriticalSection* c, const CLockLocation& locklocation)
+{
+ bool fOrderOK = true;
+ if (lockstack.get() == NULL)
+ lockstack.reset(new LockStack);
+
+ dd_mutex.lock();
+
+ (*lockstack).push_back(std::make_pair(c, locklocation));
+
+ BOOST_FOREACH(const PAIRTYPE(CCriticalSection*, CLockLocation)& i, (*lockstack))
+ {
+ if (i.first == c) break;
+
+ std::pair<CCriticalSection*, CCriticalSection*> p1 = std::make_pair(i.first, c);
+ if (lockorders.count(p1))
+ continue;
+ lockorders[p1] = (*lockstack);
+
+ std::pair<CCriticalSection*, CCriticalSection*> p2 = std::make_pair(c, i.first);
+ if (lockorders.count(p2))
+ {
+ potential_deadlock_detected(lockorders[p2], lockorders[p1]);
+ break;
+ }
+ }
+ dd_mutex.unlock();
+}
+
+static void pop_lock()
+{
+ (*lockstack).pop_back();
+}
+
+void CCriticalSection::Enter(const char* pszName, const char* pszFile, int nLine)
+{
+ push_lock(this, CLockLocation(pszName, pszFile, nLine));
+ mutex.lock();
+}
+void CCriticalSection::Leave()
+{
+ mutex.unlock();
+ pop_lock();
+}
+bool CCriticalSection::TryEnter(const char* pszName, const char* pszFile, int nLine)
+{
+ push_lock(this, CLockLocation(pszName, pszFile, nLine));
+ bool result = mutex.try_lock();
+ if (!result) pop_lock();
+ return result;
+}
+
+#else
+
+void CCriticalSection::Enter(const char*, const char*, int)
+{
+ mutex.lock();
+}
+
+void CCriticalSection::Leave()
+{
+ mutex.unlock();
+}
+
+bool CCriticalSection::TryEnter(const char*, const char*, int)
+{
+ bool result = mutex.try_lock();
+ return result;
+}
+#endif /* DEBUG_LOCKORDER */