1 files changed, 52 insertions, 45 deletions

diff --git a/src/sync.cpp b/src/sync.cpp
index 1837e8d53..fce57f1df 100644
--- a/src/sync.cpp
+++ b/src/sync.cpp
@@ -1,4 +1,4 @@
-// Copyright (c) 2011-2012 The Bitcoin Core developers
+// Copyright (c) 2011-2016 The Bitcoin Core developers
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
@@ -56,60 +56,49 @@ private:
 };
 
 typedef std::vector<std::pair<void*, CLockLocation> > LockStack;
+typedef std::map<std::pair<void*, void*>, LockStack> LockOrders;
+typedef std::set<std::pair<void*, void*> > InvLockOrders;
 
-static boost::mutex dd_mutex;
-static std::map<std::pair<void*, void*>, LockStack> lockorders;
-static boost::thread_specific_ptr<LockStack> lockstack;
+struct LockData {
+    // Very ugly hack: as the global constructs and destructors run single
+    // threaded, we use this boolean to know whether LockData still exists,
+    // as DeleteLock can get called by global CCriticalSection destructors
+    // after LockData disappears.
+    bool available;
+    LockData() : available(true) {}
+    ~LockData() { available = false; }
 
+    LockOrders lockorders;
+    InvLockOrders invlockorders;
+    boost::mutex dd_mutex;
+} static lockdata;
+
+boost::thread_specific_ptr<LockStack> lockstack;
 
 static void potential_deadlock_detected(const std::pair<void*, void*>& mismatch, const LockStack& s1, const LockStack& s2)
 {
-    // We attempt to not assert on probably-not deadlocks by assuming that
-    // a try lock will immediately have otherwise bailed if it had
-    // failed to get the lock
-    // We do this by, for the locks which triggered the potential deadlock,
-    // in either lockorder, checking that the second of the two which is locked
-    // is only a TRY_LOCK, ignoring locks if they are reentrant.
-    bool firstLocked = false;
-    bool secondLocked = false;
-    bool onlyMaybeDeadlock = false;
-
     LogPrintf("POTENTIAL DEADLOCK DETECTED\n");
     LogPrintf("Previous lock order was:\n");
     BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, s2) {
         if (i.first == mismatch.first) {
             LogPrintf(" (1)");
-            if (!firstLocked && secondLocked && i.second.fTry)
-                onlyMaybeDeadlock = true;
-            firstLocked = true;
         }
         if (i.first == mismatch.second) {
             LogPrintf(" (2)");
-            if (!secondLocked && firstLocked && i.second.fTry)
-                onlyMaybeDeadlock = true;
-            secondLocked = true;
         }
         LogPrintf(" %s\n", i.second.ToString());
     }
-    firstLocked = false;
-    secondLocked = false;
     LogPrintf("Current lock order is:\n");
     BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, s1) {
         if (i.first == mismatch.first) {
             LogPrintf(" (1)");
-            if (!firstLocked && secondLocked && i.second.fTry)
-                onlyMaybeDeadlock = true;
-            firstLocked = true;
         }
         if (i.first == mismatch.second) {
             LogPrintf(" (2)");
-            if (!secondLocked && firstLocked && i.second.fTry)
-                onlyMaybeDeadlock = true;
-            secondLocked = true;
         }
         LogPrintf(" %s\n", i.second.ToString());
     }
-    assert(onlyMaybeDeadlock);
+    assert(false);
 }
 
 static void push_lock(void* c, const CLockLocation& locklocation, bool fTry)
@@ -117,33 +106,29 @@ static void push_lock(void* c, const CLockLocation& locklocation, bool fTry)
     if (lockstack.get() == NULL)
         lockstack.reset(new LockStack);
 
-    dd_mutex.lock();
+    boost::unique_lock<boost::mutex> lock(lockdata.dd_mutex);
 
     (*lockstack).push_back(std::make_pair(c, locklocation));
 
-    if (!fTry) {
-        BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, (*lockstack)) {
-            if (i.first == c)
-                break;
+    BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, (*lockstack)) {
+        if (i.first == c)
+            break;
 
-            std::pair<void*, void*> p1 = std::make_pair(i.first, c);
-            if (lockorders.count(p1))
-                continue;
-            lockorders[p1] = (*lockstack);
+        std::pair<void*, void*> p1 = std::make_pair(i.first, c);
+        if (lockdata.lockorders.count(p1))
+            continue;
+        lockdata.lockorders[p1] = (*lockstack);
 
-            std::pair<void*, void*> p2 = std::make_pair(c, i.first);
-            if (lockorders.count(p2))
-                potential_deadlock_detected(p1, lockorders[p2], lockorders[p1]);
-        }
+        std::pair<void*, void*> p2 = std::make_pair(c, i.first);
+        lockdata.invlockorders.insert(p2);
+        if (lockdata.lockorders.count(p2))
+            potential_deadlock_detected(p1, lockdata.lockorders[p2], lockdata.lockorders[p1]);
     }
-    dd_mutex.unlock();
 }
 
 static void pop_lock()
 {
-    dd_mutex.lock();
     (*lockstack).pop_back();
-    dd_mutex.unlock();
 }
 
 void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry)
@@ -173,4 +158,26 @@ void AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine,
     abort();
 }
 
+void DeleteLock(void* cs)
+{
+    if (!lockdata.available) {
+        // We're already shutting down.
+        return;
+    }
+    boost::unique_lock<boost::mutex> lock(lockdata.dd_mutex);
+    std::pair<void*, void*> item = std::make_pair(cs, (void*)0);
+    LockOrders::iterator it = lockdata.lockorders.lower_bound(item);
+    while (it != lockdata.lockorders.end() && it->first.first == cs) {
+        std::pair<void*, void*> invitem = std::make_pair(it->first.second, it->first.first);
+        lockdata.invlockorders.erase(invitem);
+        lockdata.lockorders.erase(it++);
+    }
+    InvLockOrders::iterator invit = lockdata.invlockorders.lower_bound(item);
+    while (invit != lockdata.invlockorders.end() && invit->first == cs) {
+        std::pair<void*, void*> invinvitem = std::make_pair(invit->second, invit->first);
+        lockdata.lockorders.erase(invinvitem);
+        lockdata.invlockorders.erase(invit++);
+    }
+}
+
 #endif /* DEBUG_LOCKORDER */