Replace http with https: in links to the MIT license.

[VerusCoin.git] / src / sync.cpp

diff --git a/src/sync.cpp b/src/sync.cpp
index 066c1ca7446dac8d89c26ea4e63d4ce2d02d0c27..91a6745c05699d6e238d76bdb669bda9cef7d55f 100644 (file)
--- a/src/sync.cpp
+++ b/src/sync.cpp
@@ -1,15 +1,16 @@
-// Copyright (c) 2011-2012 The Bitcoin developers
-// Distributed under the MIT/X11 software license, see the accompanying
-// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+// Copyright (c) 2011-2012 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or https://www.opensource.org/licenses/mit-license.php .
 
 #include "sync.h"
 
 #include "util.h"
 #include "utilstrencodings.h"
 
+#include <stdio.h>
+
 #include <boost/foreach.hpp>
 #include <boost/thread.hpp>
-#include <stdio.h>
 
 #ifdef DEBUG_LOCKCONTENTION
 void PrintLockContention(const char* pszName, const char* pszFile, int nLine)
@@ -31,29 +32,30 @@ void PrintLockContention(const char* pszName, const char* pszFile, int nLine)
 // Complain if any thread tries to lock in a different order.
 //
 
-struct CLockLocation
-{
-    CLockLocation(const char* pszName, const char* pszFile, int nLine)
+struct CLockLocation {
+    CLockLocation(const char* pszName, const char* pszFile, int nLine, bool fTryIn)
     {
         mutexName = pszName;
         sourceFile = pszFile;
         sourceLine = nLine;
+        fTry = fTryIn;
     }
 
     std::string ToString() const
     {
-        return mutexName+"  "+sourceFile+":"+itostr(sourceLine);
+        return mutexName + "  " + sourceFile + ":" + itostr(sourceLine) + (fTry ? " (TRY)" : "");
     }
 
     std::string MutexName() const { return mutexName; }
 
+    bool fTry;
 private:
     std::string mutexName;
     std::string sourceFile;
     int sourceLine;
 };
 
-typedef std::vector< std::pair<void*, CLockLocation> > LockStack;
+typedef std::vector<std::pair<void*, CLockLocation> > LockStack;
 
 static boost::mutex dd_mutex;
 static std::map<std::pair<void*, void*>, LockStack> lockorders;
@@ -62,21 +64,52 @@ static 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 (i.first == mismatch.second) LogPrintf(" (2)");
+    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 (i.first == mismatch.second) LogPrintf(" (2)");
+    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);
 }
 
 static void push_lock(void* c, const CLockLocation& locklocation, bool fTry)
@@ -84,14 +117,14 @@ static void push_lock(void* c, const CLockLocation& locklocation, bool fTry)
     if (lockstack.get() == NULL)
         lockstack.reset(new LockStack);
 
-    LogPrint("lock", "Locking: %s\n", locklocation.ToString());
     dd_mutex.lock();
 
     (*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))
@@ -100,10 +133,7 @@ static void push_lock(void* c, const CLockLocation& locklocation, bool fTry)
 
             std::pair<void*, void*> p2 = std::make_pair(c, i.first);
             if (lockorders.count(p2))
-            {
                 potential_deadlock_detected(p1, lockorders[p2], lockorders[p1]);
-                break;
-            }
         }
     }
     dd_mutex.unlock();
@@ -111,11 +141,6 @@ static void push_lock(void* c, const CLockLocation& locklocation, bool fTry)
 
 static void pop_lock()
 {
-    if (fDebug)
-    {
-        const CLockLocation& locklocation = (*lockstack).rbegin()->second;
-        LogPrint("lock", "Unlocked: %s\n", locklocation.ToString());
-    }
     dd_mutex.lock();
     (*lockstack).pop_back();
     dd_mutex.unlock();
@@ -123,7 +148,7 @@ static void pop_lock()
 
 void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry)
 {
-    push_lock(cs, CLockLocation(pszName, pszFile, nLine), fTry);
+    push_lock(cs, CLockLocation(pszName, pszFile, nLine, fTry), fTry);
 }
 
 void LeaveCritical()
@@ -134,17 +159,17 @@ void LeaveCritical()
 std::string LocksHeld()
 {
     std::string result;
-    BOOST_FOREACH(const PAIRTYPE(void*, CLockLocation)&i, *lockstack)
+    BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, *lockstack)
         result += i.second.ToString() + std::string("\n");
     return result;
 }
 
-void AssertLockHeldInternal(const char *pszName, const char* pszFile, int nLine, void *cs)
+void AssertLockHeldInternal(const char* pszName, const char* pszFile, int nLine, void* cs)
 {
-    BOOST_FOREACH(const PAIRTYPE(void*, CLockLocation)&i, *lockstack)
-        if (i.first == cs) return;
-    fprintf(stderr, "Assertion failed: lock %s not held in %s:%i; locks held:\n%s",
-            pszName, pszFile, nLine, LocksHeld().c_str());
+    BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, *lockstack)
+        if (i.first == cs)
+            return;
+    fprintf(stderr, "Assertion failed: lock %s not held in %s:%i; locks held:\n%s", pszName, pszFile, nLine, LocksHeld().c_str());
     abort();
 }