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Adjust the refcounts to avoid Mutex leak #6231

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Merged
scw00 merged 1 commit into from
Dec 4, 2019
Merged

Adjust the refcounts to avoid Mutex leak #6231

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40 changes: 37 additions & 3 deletions iocore/eventsystem/I_Lock.h
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Original file line number Diff line number Diff line change
Expand Up @@ -256,7 +256,7 @@ Mutex_trylock(
#ifdef DEBUG
const SourceLocation &location, const char *ahandler,
#endif
Ptr<ProxyMutex> &m, EThread *t)
ProxyMutex *m, EThread *t)
{
ink_assert(t != nullptr);
ink_assert(t == reinterpret_cast<EThread *>(this_thread()));
Expand Down Expand Up @@ -295,12 +295,26 @@ Mutex_trylock(
return true;
}

inline bool
Mutex_trylock(
#ifdef DEBUG
const SourceLocation &location, const char *ahandler,
#endif
Ptr<ProxyMutex> &m, EThread *t)
{
return Mutex_trylock(
#ifdef DEBUG
location, ahandler,
#endif
m.get(), t);
}

inline int
Mutex_lock(
#ifdef DEBUG
const SourceLocation &location, const char *ahandler,
#endif
Ptr<ProxyMutex> &m, EThread *t)
ProxyMutex *m, EThread *t)
{
ink_assert(t != nullptr);
if (m->thread_holding != t) {
Expand All @@ -327,8 +341,22 @@ Mutex_lock(
return true;
}

inline int
Mutex_lock(
#ifdef DEBUG
const SourceLocation &location, const char *ahandler,
#endif
Ptr<ProxyMutex> &m, EThread *t)
{
return Mutex_lock(
#ifdef DEBUG
location, ahandler,
#endif
m.get(), t);
}

inline void
Mutex_unlock(Ptr<ProxyMutex> &m, EThread *t)
Mutex_unlock(ProxyMutex *m, EThread *t)
{
if (m->nthread_holding) {
ink_assert(t == m->thread_holding);
Expand All @@ -351,6 +379,12 @@ Mutex_unlock(Ptr<ProxyMutex> &m, EThread *t)
}
}

inline void
Mutex_unlock(Ptr<ProxyMutex> &m, EThread *t)
{
Mutex_unlock(m.get(), t);
}

class WeakMutexLock
{
private:
Expand Down
19 changes: 11 additions & 8 deletions src/traffic_server/InkIOCoreAPI.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -235,14 +235,17 @@ TSEventThreadSelf(void)

////////////////////////////////////////////////////////////////////
//
// Mutexes
// Mutexes: For TSMutexCreate and TSMutexDestroy, the refcount of the
// ProxyMutex object is not incremented or decremented. If the resulting
// ProxyMutex is passed to a INKContInternal, it's mutex smart pointer
// will take ownership of the ProxyMutex and delete it when the last
// reference is removed. TSMutexDestroy should not be called in that case.
//
////////////////////////////////////////////////////////////////////
TSMutex
TSMutexCreate()
{
ProxyMutex *mutexp = new_ProxyMutex();
mutexp->refcount_inc();

// TODO: Remove this when allocations can never fail.
sdk_assert(sdk_sanity_check_mutex((TSMutex)mutexp) == TS_SUCCESS);
Expand All @@ -255,9 +258,9 @@ TSMutexDestroy(TSMutex m)
{
sdk_assert(sdk_sanity_check_mutex(m) == TS_SUCCESS);
ProxyMutex *mutexp = reinterpret_cast<ProxyMutex *>(m);
// Decrement the refcount added in TSMutexCreate. Delete if this
// was the last ref count
if (mutexp && mutexp->refcount_dec() == 0) {

if (mutexp) {
ink_release_assert(mutexp->refcount() == 0);
mutexp->free();
}
}
Expand Down Expand Up @@ -296,23 +299,23 @@ void
TSMutexLock(TSMutex mutexp)
{
sdk_assert(sdk_sanity_check_mutex(mutexp) == TS_SUCCESS);
Ptr<ProxyMutex> proxy_mutex(reinterpret_cast<ProxyMutex *>(mutexp));
ProxyMutex *proxy_mutex = reinterpret_cast<ProxyMutex *>(mutexp);
MUTEX_TAKE_LOCK(proxy_mutex, this_ethread());
}

TSReturnCode
TSMutexLockTry(TSMutex mutexp)
{
sdk_assert(sdk_sanity_check_mutex(mutexp) == TS_SUCCESS);
Ptr<ProxyMutex> proxy_mutex(reinterpret_cast<ProxyMutex *>(mutexp));
ProxyMutex *proxy_mutex = reinterpret_cast<ProxyMutex *>(mutexp);
return (MUTEX_TAKE_TRY_LOCK(proxy_mutex, this_ethread()) ? TS_SUCCESS : TS_ERROR);
}

void
TSMutexUnlock(TSMutex mutexp)
{
sdk_assert(sdk_sanity_check_mutex(mutexp) == TS_SUCCESS);
Ptr<ProxyMutex> proxy_mutex(reinterpret_cast<ProxyMutex *>(mutexp));
ProxyMutex *proxy_mutex(reinterpret_cast<ProxyMutex *>(mutexp));
MUTEX_UNTAKE_LOCK(proxy_mutex, this_ethread());
}

Expand Down