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MCOL-744 Fix BPP mutex crash

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Whilst very rare we can hit a case where we attempt to unlock objLock
when it is already unlocked. With the Boost version in Ubuntu 16.04 this
triggers an abort() effectively crashing PrimProc.

In this patch we switch to a pthread mutex instead which does not have
this limitation. At a later date we can look into refactoring how BPP
and this mutex works.
This commit is contained in:
Andrew Hutchings
2017-08-11 07:17:07 +01:00
parent 76fb89c13f
commit fa17a98d60
2 changed files with 19 additions and 16 deletions
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26
primitives/primproc/batchprimitiveprocessor.cpp
View File

@ -112,6 +112,7 @@ BatchPrimitiveProcessor::BatchPrimitiveProcessor() :
{
pp.setLogicalBlockMode(true);
pp.setBlockPtr((int *) blockData);
pthread_mutex_init(&objLock,NULL);
}
BatchPrimitiveProcessor::BatchPrimitiveProcessor(ByteStream &b, double prefetch,
@ -153,6 +154,7 @@ BatchPrimitiveProcessor::BatchPrimitiveProcessor(ByteStream &b, double prefetch,
pp.setLogicalBlockMode(true);
pp.setBlockPtr((int *) blockData);
sendThread = bppst;
pthread_mutex_init(&objLock, NULL);
initBPP(b);
// cerr << "made a BPP\n";
}
@ -175,6 +177,7 @@ BatchPrimitiveProcessor::~BatchPrimitiveProcessor()
counterLock.lock();
}
counterLock.unlock();
pthread_mutex_destroy(&objLock);
}
/**
@ -233,7 +236,7 @@ void BatchPrimitiveProcessor::initBPP(ByteStream &bs)
}
if (doJoin) {
objLock.lock();
pthread_mutex_lock(&objLock);
if (ot == ROW_GROUP) {
bs >> joinerCount;
// cout << "joinerCount = " << joinerCount << endl;
@ -325,7 +328,7 @@ void BatchPrimitiveProcessor::initBPP(ByteStream &bs)
joiner.reset(new Joiner((bool) tmp8));
}
#ifdef __FreeBSD__
objLock.unlock();
pthread_mutex_unlock(&objLock);
#endif
}
@ -401,7 +404,7 @@ void BatchPrimitiveProcessor::resetBPP(ByteStream &bs, const SP_UM_MUTEX& w,
uint32_t i;
vector<uint64_t> preloads;
objLock.lock();
pthread_mutex_lock(&objLock);
writelock = w;
sock = s;
@ -452,7 +455,7 @@ void BatchPrimitiveProcessor::resetBPP(ByteStream &bs, const SP_UM_MUTEX& w,
buildVSSCache(count);
#ifdef __FreeBSD__
objLock.unlock();
pthread_mutex_unlock(&objLock);
#endif
}
@ -599,7 +602,7 @@ int BatchPrimitiveProcessor::endOfJoiner()
#endif
#ifndef __FreeBSD__
objLock.unlock();
pthread_mutex_unlock(&objLock);
#endif
return 0;
}
@ -1486,7 +1489,7 @@ void BatchPrimitiveProcessor::execute()
#endif
#ifndef __FreeBSD__
objLock.unlock();
pthread_mutex_unlock(&objLock);
#endif
throw n; // need to pass this through to BPPSeeder
}
@ -1777,12 +1780,7 @@ int BatchPrimitiveProcessor::operator()()
vssCache.clear();
#ifndef __FreeBSD__
// If we've been aborted the lock *may* have been released already
// By doing try_lock, we ensure the unlock will work whether it was
// locked or not.
if (sendThread->aborted())
objLock.try_lock();
objLock.unlock();
pthread_mutex_unlock(&objLock);
#endif
freeLargeBuffers();
#ifdef PRIMPROC_STOPWATCH
@ -1881,7 +1879,7 @@ SBPP BatchPrimitiveProcessor::duplicate()
}
bpp->doJoin = doJoin;
if (doJoin) {
bpp->objLock.lock();
pthread_mutex_lock(&bpp->objLock);
bpp->joinerSize = joinerSize;
if (ot == ROW_GROUP) {
/* There are add'l join vars, but only these are necessary for processing
@ -1921,7 +1919,7 @@ SBPP BatchPrimitiveProcessor::duplicate()
else
bpp->joiner = joiner;
#ifdef __FreeBSD__
bpp->objLock.unlock();
pthread_mutex_unlock(&bpp->objLock);
#endif
}

9
primitives/primproc/batchprimitiveprocessor.h
View File

@ -121,7 +121,7 @@ class BatchPrimitiveProcessor
// these two functions are used by BPPV to create BPP instances
// on demand. TRY not to use unlock() for anything else.
void unlock() { objLock.try_lock(); objLock.unlock(); }
void unlock() { pthread_mutex_unlock(&objLock); }
bool hasJoin() { return doJoin; }
private:
BatchPrimitiveProcessor();
@ -200,7 +200,12 @@ class BatchPrimitiveProcessor
messageqcpp::SBS serialized;
SP_UM_MUTEX writelock;
boost::mutex objLock;
// MCOL-744 using pthread mutex instead of Boost mutex because
// in it is possible that this lock could be unlocked when it is
// already unlocked. In Ubuntu 16.04's Boost this triggers a
// crash. Whilst it is very hard to hit this it is still bad.
// Longer term TODO: fix/remove objLock and/or refactor BPP
pthread_mutex_t objLock;
bool LBIDTrace;
bool fBusy;