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Merge pull request #5515

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0fcc4e1 Assert on probable deadlocks if the second lock isnt try_lock (Matt Corallo)
This commit is contained in:
Wladimir J. van der Laan 2015-07-23 18:33:47 +02:00
commit d946e9a848
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GPG Key ID: 74810B012346C9A6
1 changed files with 39 additions and 10 deletions
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49
src/sync.cpp
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@ -33,20 +33,22 @@ void PrintLockContention(const char* pszName, const char* pszFile, int nLine)
// //
struct CLockLocation { struct CLockLocation {
CLockLocation(const char* pszName, const char* pszFile, int nLine) CLockLocation(const char* pszName, const char* pszFile, int nLine, bool fTryIn)
{ {
mutexName = pszName; mutexName = pszName;
sourceFile = pszFile; sourceFile = pszFile;
sourceLine = nLine; sourceLine = nLine;
fTry = fTryIn;
} }
std::string ToString() const std::string ToString() const
{ {
return mutexName + " " + sourceFile + ":" + itostr(sourceLine); return mutexName + " " + sourceFile + ":" + itostr(sourceLine) + (fTry ? " (TRY)" : "");
} }
std::string MutexName() const { return mutexName; } std::string MutexName() const { return mutexName; }
bool fTry;
private: private:
std::string mutexName; std::string mutexName;
std::string sourceFile; std::string sourceFile;
@ -62,23 +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) 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("POTENTIAL DEADLOCK DETECTED\n");
LogPrintf("Previous lock order was:\n"); LogPrintf("Previous lock order was:\n");
BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, s2) { BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, s2) {
if (i.first == mismatch.first) if (i.first == mismatch.first) {
LogPrintf(" (1)"); LogPrintf(" (1)");
if (i.first == mismatch.second) if (!firstLocked && secondLocked && i.second.fTry)
onlyMaybeDeadlock = true;
firstLocked = true;
}
if (i.first == mismatch.second) {
LogPrintf(" (2)"); LogPrintf(" (2)");
if (!secondLocked && firstLocked && i.second.fTry)
onlyMaybeDeadlock = true;
secondLocked = true;
}
LogPrintf(" %s\n", i.second.ToString()); LogPrintf(" %s\n", i.second.ToString());
} }
firstLocked = false;
secondLocked = false;
LogPrintf("Current lock order is:\n"); LogPrintf("Current lock order is:\n");
BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, s1) { BOOST_FOREACH (const PAIRTYPE(void*, CLockLocation) & i, s1) {
if (i.first == mismatch.first) if (i.first == mismatch.first) {
LogPrintf(" (1)"); LogPrintf(" (1)");
if (i.first == mismatch.second) if (!firstLocked && secondLocked && i.second.fTry)
onlyMaybeDeadlock = true;
firstLocked = true;
}
if (i.first == mismatch.second) {
LogPrintf(" (2)"); LogPrintf(" (2)");
if (!secondLocked && firstLocked && i.second.fTry)
onlyMaybeDeadlock = true;
secondLocked = true;
}
LogPrintf(" %s\n", i.second.ToString()); LogPrintf(" %s\n", i.second.ToString());
} }
assert(onlyMaybeDeadlock);
} }
static void push_lock(void* c, const CLockLocation& locklocation, bool fTry) static void push_lock(void* c, const CLockLocation& locklocation, bool fTry)
@ -101,10 +132,8 @@ static void push_lock(void* c, const CLockLocation& locklocation, bool fTry)
lockorders[p1] = (*lockstack); lockorders[p1] = (*lockstack);
std::pair<void*, void*> p2 = std::make_pair(c, i.first); std::pair<void*, void*> p2 = std::make_pair(c, i.first);
if (lockorders.count(p2)) { if (lockorders.count(p2))
potential_deadlock_detected(p1, lockorders[p2], lockorders[p1]); potential_deadlock_detected(p1, lockorders[p2], lockorders[p1]);
break;
}
} }
} }
dd_mutex.unlock(); dd_mutex.unlock();
@ -119,7 +148,7 @@ static void pop_lock()
void EnterCritical(const char* pszName, const char* pszFile, int nLine, void* cs, bool fTry) 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() void LeaveCritical()