| //===--- PthreadLockChecker.cpp - Check for locking problems ---*- C++ -*--===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file defines: |
| // * PthreadLockChecker, a simple lock -> unlock checker. |
| // Which also checks for XNU locks, which behave similarly enough to share |
| // code. |
| // * FuchsiaLocksChecker, which is also rather similar. |
| // * C11LockChecker which also closely follows Pthread semantics. |
| // |
| // TODO: Path notes. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/StaticAnalyzer/Checkers/BuiltinCheckerRegistration.h" |
| #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h" |
| #include "clang/StaticAnalyzer/Core/Checker.h" |
| #include "clang/StaticAnalyzer/Core/CheckerManager.h" |
| #include "clang/StaticAnalyzer/Core/PathSensitive/CallEvent.h" |
| #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h" |
| |
| using namespace clang; |
| using namespace ento; |
| |
| namespace { |
| |
| struct LockState { |
| enum Kind { |
| Destroyed, |
| Locked, |
| Unlocked, |
| UntouchedAndPossiblyDestroyed, |
| UnlockedAndPossiblyDestroyed |
| } K; |
| |
| private: |
| LockState(Kind K) : K(K) {} |
| |
| public: |
| static LockState getLocked() { return LockState(Locked); } |
| static LockState getUnlocked() { return LockState(Unlocked); } |
| static LockState getDestroyed() { return LockState(Destroyed); } |
| static LockState getUntouchedAndPossiblyDestroyed() { |
| return LockState(UntouchedAndPossiblyDestroyed); |
| } |
| static LockState getUnlockedAndPossiblyDestroyed() { |
| return LockState(UnlockedAndPossiblyDestroyed); |
| } |
| |
| bool operator==(const LockState &X) const { return K == X.K; } |
| |
| bool isLocked() const { return K == Locked; } |
| bool isUnlocked() const { return K == Unlocked; } |
| bool isDestroyed() const { return K == Destroyed; } |
| bool isUntouchedAndPossiblyDestroyed() const { |
| return K == UntouchedAndPossiblyDestroyed; |
| } |
| bool isUnlockedAndPossiblyDestroyed() const { |
| return K == UnlockedAndPossiblyDestroyed; |
| } |
| |
| void Profile(llvm::FoldingSetNodeID &ID) const { ID.AddInteger(K); } |
| }; |
| |
| class PthreadLockChecker : public Checker<check::PostCall, check::DeadSymbols, |
| check::RegionChanges> { |
| public: |
| enum LockingSemantics { NotApplicable = 0, PthreadSemantics, XNUSemantics }; |
| enum CheckerKind { |
| CK_PthreadLockChecker, |
| CK_FuchsiaLockChecker, |
| CK_C11LockChecker, |
| CK_NumCheckKinds |
| }; |
| DefaultBool ChecksEnabled[CK_NumCheckKinds]; |
| CheckerNameRef CheckNames[CK_NumCheckKinds]; |
| |
| private: |
| typedef void (PthreadLockChecker::*FnCheck)(const CallEvent &Call, |
| CheckerContext &C, |
| CheckerKind CheckKind) const; |
| CallDescriptionMap<FnCheck> PThreadCallbacks = { |
| // Init. |
| {{"pthread_mutex_init", 2}, &PthreadLockChecker::InitAnyLock}, |
| // TODO: pthread_rwlock_init(2 arguments). |
| // TODO: lck_mtx_init(3 arguments). |
| // TODO: lck_mtx_alloc_init(2 arguments) => returns the mutex. |
| // TODO: lck_rw_init(3 arguments). |
| // TODO: lck_rw_alloc_init(2 arguments) => returns the mutex. |
| |
| // Acquire. |
| {{"pthread_mutex_lock", 1}, &PthreadLockChecker::AcquirePthreadLock}, |
| {{"pthread_rwlock_rdlock", 1}, &PthreadLockChecker::AcquirePthreadLock}, |
| {{"pthread_rwlock_wrlock", 1}, &PthreadLockChecker::AcquirePthreadLock}, |
| {{"lck_mtx_lock", 1}, &PthreadLockChecker::AcquireXNULock}, |
| {{"lck_rw_lock_exclusive", 1}, &PthreadLockChecker::AcquireXNULock}, |
| {{"lck_rw_lock_shared", 1}, &PthreadLockChecker::AcquireXNULock}, |
| |
| // Try. |
| {{"pthread_mutex_trylock", 1}, &PthreadLockChecker::TryPthreadLock}, |
| {{"pthread_rwlock_tryrdlock", 1}, &PthreadLockChecker::TryPthreadLock}, |
| {{"pthread_rwlock_trywrlock", 1}, &PthreadLockChecker::TryPthreadLock}, |
| {{"lck_mtx_try_lock", 1}, &PthreadLockChecker::TryXNULock}, |
| {{"lck_rw_try_lock_exclusive", 1}, &PthreadLockChecker::TryXNULock}, |
| {{"lck_rw_try_lock_shared", 1}, &PthreadLockChecker::TryXNULock}, |
| |
| // Release. |
| {{"pthread_mutex_unlock", 1}, &PthreadLockChecker::ReleaseAnyLock}, |
| {{"pthread_rwlock_unlock", 1}, &PthreadLockChecker::ReleaseAnyLock}, |
| {{"lck_mtx_unlock", 1}, &PthreadLockChecker::ReleaseAnyLock}, |
| {{"lck_rw_unlock_exclusive", 1}, &PthreadLockChecker::ReleaseAnyLock}, |
| {{"lck_rw_unlock_shared", 1}, &PthreadLockChecker::ReleaseAnyLock}, |
| {{"lck_rw_done", 1}, &PthreadLockChecker::ReleaseAnyLock}, |
| |
| // Destroy. |
| {{"pthread_mutex_destroy", 1}, &PthreadLockChecker::DestroyPthreadLock}, |
| {{"lck_mtx_destroy", 2}, &PthreadLockChecker::DestroyXNULock}, |
| // TODO: pthread_rwlock_destroy(1 argument). |
| // TODO: lck_rw_destroy(2 arguments). |
| }; |
| |
| CallDescriptionMap<FnCheck> FuchsiaCallbacks = { |
| // Init. |
| {{"spin_lock_init", 1}, &PthreadLockChecker::InitAnyLock}, |
| |
| // Acquire. |
| {{"spin_lock", 1}, &PthreadLockChecker::AcquirePthreadLock}, |
| {{"spin_lock_save", 3}, &PthreadLockChecker::AcquirePthreadLock}, |
| {{"sync_mutex_lock", 1}, &PthreadLockChecker::AcquirePthreadLock}, |
| {{"sync_mutex_lock_with_waiter", 1}, |
| &PthreadLockChecker::AcquirePthreadLock}, |
| |
| // Try. |
| {{"spin_trylock", 1}, &PthreadLockChecker::TryFuchsiaLock}, |
| {{"sync_mutex_trylock", 1}, &PthreadLockChecker::TryFuchsiaLock}, |
| {{"sync_mutex_timedlock", 2}, &PthreadLockChecker::TryFuchsiaLock}, |
| |
| // Release. |
| {{"spin_unlock", 1}, &PthreadLockChecker::ReleaseAnyLock}, |
| {{"spin_unlock_restore", 3}, &PthreadLockChecker::ReleaseAnyLock}, |
| {{"sync_mutex_unlock", 1}, &PthreadLockChecker::ReleaseAnyLock}, |
| }; |
| |
| CallDescriptionMap<FnCheck> C11Callbacks = { |
| // Init. |
| {{"mtx_init", 2}, &PthreadLockChecker::InitAnyLock}, |
| |
| // Acquire. |
| {{"mtx_lock", 1}, &PthreadLockChecker::AcquirePthreadLock}, |
| |
| // Try. |
| {{"mtx_trylock", 1}, &PthreadLockChecker::TryC11Lock}, |
| {{"mtx_timedlock", 2}, &PthreadLockChecker::TryC11Lock}, |
| |
| // Release. |
| {{"mtx_unlock", 1}, &PthreadLockChecker::ReleaseAnyLock}, |
| |
| // Destroy |
| {{"mtx_destroy", 1}, &PthreadLockChecker::DestroyPthreadLock}, |
| }; |
| |
| ProgramStateRef resolvePossiblyDestroyedMutex(ProgramStateRef state, |
| const MemRegion *lockR, |
| const SymbolRef *sym) const; |
| void reportBug(CheckerContext &C, std::unique_ptr<BugType> BT[], |
| const Expr *MtxExpr, CheckerKind CheckKind, |
| StringRef Desc) const; |
| |
| // Init. |
| void InitAnyLock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const; |
| void InitLockAux(const CallEvent &Call, CheckerContext &C, |
| const Expr *MtxExpr, SVal MtxVal, |
| CheckerKind CheckKind) const; |
| |
| // Lock, Try-lock. |
| void AcquirePthreadLock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const; |
| void AcquireXNULock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const; |
| void TryPthreadLock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const; |
| void TryXNULock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const; |
| void TryFuchsiaLock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const; |
| void TryC11Lock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const; |
| void AcquireLockAux(const CallEvent &Call, CheckerContext &C, |
| const Expr *MtxExpr, SVal MtxVal, bool IsTryLock, |
| LockingSemantics Semantics, CheckerKind CheckKind) const; |
| |
| // Release. |
| void ReleaseAnyLock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const; |
| void ReleaseLockAux(const CallEvent &Call, CheckerContext &C, |
| const Expr *MtxExpr, SVal MtxVal, |
| CheckerKind CheckKind) const; |
| |
| // Destroy. |
| void DestroyPthreadLock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const; |
| void DestroyXNULock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const; |
| void DestroyLockAux(const CallEvent &Call, CheckerContext &C, |
| const Expr *MtxExpr, SVal MtxVal, |
| LockingSemantics Semantics, CheckerKind CheckKind) const; |
| |
| public: |
| void checkPostCall(const CallEvent &Call, CheckerContext &C) const; |
| void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const; |
| ProgramStateRef |
| checkRegionChanges(ProgramStateRef State, const InvalidatedSymbols *Symbols, |
| ArrayRef<const MemRegion *> ExplicitRegions, |
| ArrayRef<const MemRegion *> Regions, |
| const LocationContext *LCtx, const CallEvent *Call) const; |
| void printState(raw_ostream &Out, ProgramStateRef State, const char *NL, |
| const char *Sep) const override; |
| |
| private: |
| mutable std::unique_ptr<BugType> BT_doublelock[CK_NumCheckKinds]; |
| mutable std::unique_ptr<BugType> BT_doubleunlock[CK_NumCheckKinds]; |
| mutable std::unique_ptr<BugType> BT_destroylock[CK_NumCheckKinds]; |
| mutable std::unique_ptr<BugType> BT_initlock[CK_NumCheckKinds]; |
| mutable std::unique_ptr<BugType> BT_lor[CK_NumCheckKinds]; |
| |
| void initBugType(CheckerKind CheckKind) const { |
| if (BT_doublelock[CheckKind]) |
| return; |
| BT_doublelock[CheckKind].reset( |
| new BugType{CheckNames[CheckKind], "Double locking", "Lock checker"}); |
| BT_doubleunlock[CheckKind].reset( |
| new BugType{CheckNames[CheckKind], "Double unlocking", "Lock checker"}); |
| BT_destroylock[CheckKind].reset(new BugType{ |
| CheckNames[CheckKind], "Use destroyed lock", "Lock checker"}); |
| BT_initlock[CheckKind].reset(new BugType{ |
| CheckNames[CheckKind], "Init invalid lock", "Lock checker"}); |
| BT_lor[CheckKind].reset(new BugType{CheckNames[CheckKind], |
| "Lock order reversal", "Lock checker"}); |
| } |
| }; |
| } // end anonymous namespace |
| |
| // A stack of locks for tracking lock-unlock order. |
| REGISTER_LIST_WITH_PROGRAMSTATE(LockSet, const MemRegion *) |
| |
| // An entry for tracking lock states. |
| REGISTER_MAP_WITH_PROGRAMSTATE(LockMap, const MemRegion *, LockState) |
| |
| // Return values for unresolved calls to pthread_mutex_destroy(). |
| REGISTER_MAP_WITH_PROGRAMSTATE(DestroyRetVal, const MemRegion *, SymbolRef) |
| |
| void PthreadLockChecker::checkPostCall(const CallEvent &Call, |
| CheckerContext &C) const { |
| // An additional umbrella check that all functions modeled by this checker |
| // are global C functions. |
| // TODO: Maybe make this the default behavior of CallDescription |
| // with exactly one identifier? |
| // FIXME: Try to handle cases when the implementation was inlined rather |
| // than just giving up. |
| if (!Call.isGlobalCFunction() || C.wasInlined) |
| return; |
| |
| if (const FnCheck *Callback = PThreadCallbacks.lookup(Call)) |
| (this->**Callback)(Call, C, CK_PthreadLockChecker); |
| else if (const FnCheck *Callback = FuchsiaCallbacks.lookup(Call)) |
| (this->**Callback)(Call, C, CK_FuchsiaLockChecker); |
| else if (const FnCheck *Callback = C11Callbacks.lookup(Call)) |
| (this->**Callback)(Call, C, CK_C11LockChecker); |
| } |
| |
| // When a lock is destroyed, in some semantics(like PthreadSemantics) we are not |
| // sure if the destroy call has succeeded or failed, and the lock enters one of |
| // the 'possibly destroyed' state. There is a short time frame for the |
| // programmer to check the return value to see if the lock was successfully |
| // destroyed. Before we model the next operation over that lock, we call this |
| // function to see if the return value was checked by now and set the lock state |
| // - either to destroyed state or back to its previous state. |
| |
| // In PthreadSemantics, pthread_mutex_destroy() returns zero if the lock is |
| // successfully destroyed and it returns a non-zero value otherwise. |
| ProgramStateRef PthreadLockChecker::resolvePossiblyDestroyedMutex( |
| ProgramStateRef state, const MemRegion *lockR, const SymbolRef *sym) const { |
| const LockState *lstate = state->get<LockMap>(lockR); |
| // Existence in DestroyRetVal ensures existence in LockMap. |
| // Existence in Destroyed also ensures that the lock state for lockR is either |
| // UntouchedAndPossiblyDestroyed or UnlockedAndPossiblyDestroyed. |
| assert(lstate->isUntouchedAndPossiblyDestroyed() || |
| lstate->isUnlockedAndPossiblyDestroyed()); |
| |
| ConstraintManager &CMgr = state->getConstraintManager(); |
| ConditionTruthVal retZero = CMgr.isNull(state, *sym); |
| if (retZero.isConstrainedFalse()) { |
| if (lstate->isUntouchedAndPossiblyDestroyed()) |
| state = state->remove<LockMap>(lockR); |
| else if (lstate->isUnlockedAndPossiblyDestroyed()) |
| state = state->set<LockMap>(lockR, LockState::getUnlocked()); |
| } else |
| state = state->set<LockMap>(lockR, LockState::getDestroyed()); |
| |
| // Removing the map entry (lockR, sym) from DestroyRetVal as the lock state is |
| // now resolved. |
| state = state->remove<DestroyRetVal>(lockR); |
| return state; |
| } |
| |
| void PthreadLockChecker::printState(raw_ostream &Out, ProgramStateRef State, |
| const char *NL, const char *Sep) const { |
| LockMapTy LM = State->get<LockMap>(); |
| if (!LM.isEmpty()) { |
| Out << Sep << "Mutex states:" << NL; |
| for (auto I : LM) { |
| I.first->dumpToStream(Out); |
| if (I.second.isLocked()) |
| Out << ": locked"; |
| else if (I.second.isUnlocked()) |
| Out << ": unlocked"; |
| else if (I.second.isDestroyed()) |
| Out << ": destroyed"; |
| else if (I.second.isUntouchedAndPossiblyDestroyed()) |
| Out << ": not tracked, possibly destroyed"; |
| else if (I.second.isUnlockedAndPossiblyDestroyed()) |
| Out << ": unlocked, possibly destroyed"; |
| Out << NL; |
| } |
| } |
| |
| LockSetTy LS = State->get<LockSet>(); |
| if (!LS.isEmpty()) { |
| Out << Sep << "Mutex lock order:" << NL; |
| for (auto I : LS) { |
| I->dumpToStream(Out); |
| Out << NL; |
| } |
| } |
| |
| DestroyRetValTy DRV = State->get<DestroyRetVal>(); |
| if (!DRV.isEmpty()) { |
| Out << Sep << "Mutexes in unresolved possibly destroyed state:" << NL; |
| for (auto I : DRV) { |
| I.first->dumpToStream(Out); |
| Out << ": "; |
| I.second->dumpToStream(Out); |
| Out << NL; |
| } |
| } |
| } |
| |
| void PthreadLockChecker::AcquirePthreadLock(const CallEvent &Call, |
| CheckerContext &C, |
| CheckerKind CheckKind) const { |
| AcquireLockAux(Call, C, Call.getArgExpr(0), Call.getArgSVal(0), false, |
| PthreadSemantics, CheckKind); |
| } |
| |
| void PthreadLockChecker::AcquireXNULock(const CallEvent &Call, |
| CheckerContext &C, |
| CheckerKind CheckKind) const { |
| AcquireLockAux(Call, C, Call.getArgExpr(0), Call.getArgSVal(0), false, |
| XNUSemantics, CheckKind); |
| } |
| |
| void PthreadLockChecker::TryPthreadLock(const CallEvent &Call, |
| CheckerContext &C, |
| CheckerKind CheckKind) const { |
| AcquireLockAux(Call, C, Call.getArgExpr(0), Call.getArgSVal(0), true, |
| PthreadSemantics, CheckKind); |
| } |
| |
| void PthreadLockChecker::TryXNULock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const { |
| AcquireLockAux(Call, C, Call.getArgExpr(0), Call.getArgSVal(0), true, |
| PthreadSemantics, CheckKind); |
| } |
| |
| void PthreadLockChecker::TryFuchsiaLock(const CallEvent &Call, |
| CheckerContext &C, |
| CheckerKind CheckKind) const { |
| AcquireLockAux(Call, C, Call.getArgExpr(0), Call.getArgSVal(0), true, |
| PthreadSemantics, CheckKind); |
| } |
| |
| void PthreadLockChecker::TryC11Lock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const { |
| AcquireLockAux(Call, C, Call.getArgExpr(0), Call.getArgSVal(0), true, |
| PthreadSemantics, CheckKind); |
| } |
| |
| void PthreadLockChecker::AcquireLockAux(const CallEvent &Call, |
| CheckerContext &C, const Expr *MtxExpr, |
| SVal MtxVal, bool IsTryLock, |
| enum LockingSemantics Semantics, |
| CheckerKind CheckKind) const { |
| if (!ChecksEnabled[CheckKind]) |
| return; |
| |
| const MemRegion *lockR = MtxVal.getAsRegion(); |
| if (!lockR) |
| return; |
| |
| ProgramStateRef state = C.getState(); |
| const SymbolRef *sym = state->get<DestroyRetVal>(lockR); |
| if (sym) |
| state = resolvePossiblyDestroyedMutex(state, lockR, sym); |
| |
| if (const LockState *LState = state->get<LockMap>(lockR)) { |
| if (LState->isLocked()) { |
| reportBug(C, BT_doublelock, MtxExpr, CheckKind, |
| "This lock has already been acquired"); |
| return; |
| } else if (LState->isDestroyed()) { |
| reportBug(C, BT_destroylock, MtxExpr, CheckKind, |
| "This lock has already been destroyed"); |
| return; |
| } |
| } |
| |
| ProgramStateRef lockSucc = state; |
| if (IsTryLock) { |
| // Bifurcate the state, and allow a mode where the lock acquisition fails. |
| SVal RetVal = Call.getReturnValue(); |
| if (auto DefinedRetVal = RetVal.getAs<DefinedSVal>()) { |
| ProgramStateRef lockFail; |
| switch (Semantics) { |
| case PthreadSemantics: |
| std::tie(lockFail, lockSucc) = state->assume(*DefinedRetVal); |
| break; |
| case XNUSemantics: |
| std::tie(lockSucc, lockFail) = state->assume(*DefinedRetVal); |
| break; |
| default: |
| llvm_unreachable("Unknown tryLock locking semantics"); |
| } |
| assert(lockFail && lockSucc); |
| C.addTransition(lockFail); |
| } |
| // We might want to handle the case when the mutex lock function was inlined |
| // and returned an Unknown or Undefined value. |
| } else if (Semantics == PthreadSemantics) { |
| // Assume that the return value was 0. |
| SVal RetVal = Call.getReturnValue(); |
| if (auto DefinedRetVal = RetVal.getAs<DefinedSVal>()) { |
| // FIXME: If the lock function was inlined and returned true, |
| // we need to behave sanely - at least generate sink. |
| lockSucc = state->assume(*DefinedRetVal, false); |
| assert(lockSucc); |
| } |
| // We might want to handle the case when the mutex lock function was inlined |
| // and returned an Unknown or Undefined value. |
| } else { |
| // XNU locking semantics return void on non-try locks |
| assert((Semantics == XNUSemantics) && "Unknown locking semantics"); |
| lockSucc = state; |
| } |
| |
| // Record that the lock was acquired. |
| lockSucc = lockSucc->add<LockSet>(lockR); |
| lockSucc = lockSucc->set<LockMap>(lockR, LockState::getLocked()); |
| C.addTransition(lockSucc); |
| } |
| |
| void PthreadLockChecker::ReleaseAnyLock(const CallEvent &Call, |
| CheckerContext &C, |
| CheckerKind CheckKind) const { |
| ReleaseLockAux(Call, C, Call.getArgExpr(0), Call.getArgSVal(0), CheckKind); |
| } |
| |
| void PthreadLockChecker::ReleaseLockAux(const CallEvent &Call, |
| CheckerContext &C, const Expr *MtxExpr, |
| SVal MtxVal, |
| CheckerKind CheckKind) const { |
| if (!ChecksEnabled[CheckKind]) |
| return; |
| |
| const MemRegion *lockR = MtxVal.getAsRegion(); |
| if (!lockR) |
| return; |
| |
| ProgramStateRef state = C.getState(); |
| const SymbolRef *sym = state->get<DestroyRetVal>(lockR); |
| if (sym) |
| state = resolvePossiblyDestroyedMutex(state, lockR, sym); |
| |
| if (const LockState *LState = state->get<LockMap>(lockR)) { |
| if (LState->isUnlocked()) { |
| reportBug(C, BT_doubleunlock, MtxExpr, CheckKind, |
| "This lock has already been unlocked"); |
| return; |
| } else if (LState->isDestroyed()) { |
| reportBug(C, BT_destroylock, MtxExpr, CheckKind, |
| "This lock has already been destroyed"); |
| return; |
| } |
| } |
| |
| LockSetTy LS = state->get<LockSet>(); |
| |
| if (!LS.isEmpty()) { |
| const MemRegion *firstLockR = LS.getHead(); |
| if (firstLockR != lockR) { |
| reportBug(C, BT_lor, MtxExpr, CheckKind, |
| "This was not the most recently acquired lock. Possible lock " |
| "order reversal"); |
| return; |
| } |
| // Record that the lock was released. |
| state = state->set<LockSet>(LS.getTail()); |
| } |
| |
| state = state->set<LockMap>(lockR, LockState::getUnlocked()); |
| C.addTransition(state); |
| } |
| |
| void PthreadLockChecker::DestroyPthreadLock(const CallEvent &Call, |
| CheckerContext &C, |
| CheckerKind CheckKind) const { |
| DestroyLockAux(Call, C, Call.getArgExpr(0), Call.getArgSVal(0), |
| PthreadSemantics, CheckKind); |
| } |
| |
| void PthreadLockChecker::DestroyXNULock(const CallEvent &Call, |
| CheckerContext &C, |
| CheckerKind CheckKind) const { |
| DestroyLockAux(Call, C, Call.getArgExpr(0), Call.getArgSVal(0), XNUSemantics, |
| CheckKind); |
| } |
| |
| void PthreadLockChecker::DestroyLockAux(const CallEvent &Call, |
| CheckerContext &C, const Expr *MtxExpr, |
| SVal MtxVal, |
| enum LockingSemantics Semantics, |
| CheckerKind CheckKind) const { |
| if (!ChecksEnabled[CheckKind]) |
| return; |
| |
| const MemRegion *LockR = MtxVal.getAsRegion(); |
| if (!LockR) |
| return; |
| |
| ProgramStateRef State = C.getState(); |
| |
| const SymbolRef *sym = State->get<DestroyRetVal>(LockR); |
| if (sym) |
| State = resolvePossiblyDestroyedMutex(State, LockR, sym); |
| |
| const LockState *LState = State->get<LockMap>(LockR); |
| // Checking the return value of the destroy method only in the case of |
| // PthreadSemantics |
| if (Semantics == PthreadSemantics) { |
| if (!LState || LState->isUnlocked()) { |
| SymbolRef sym = Call.getReturnValue().getAsSymbol(); |
| if (!sym) { |
| State = State->remove<LockMap>(LockR); |
| C.addTransition(State); |
| return; |
| } |
| State = State->set<DestroyRetVal>(LockR, sym); |
| if (LState && LState->isUnlocked()) |
| State = State->set<LockMap>( |
| LockR, LockState::getUnlockedAndPossiblyDestroyed()); |
| else |
| State = State->set<LockMap>( |
| LockR, LockState::getUntouchedAndPossiblyDestroyed()); |
| C.addTransition(State); |
| return; |
| } |
| } else { |
| if (!LState || LState->isUnlocked()) { |
| State = State->set<LockMap>(LockR, LockState::getDestroyed()); |
| C.addTransition(State); |
| return; |
| } |
| } |
| |
| StringRef Message = LState->isLocked() |
| ? "This lock is still locked" |
| : "This lock has already been destroyed"; |
| |
| reportBug(C, BT_destroylock, MtxExpr, CheckKind, Message); |
| } |
| |
| void PthreadLockChecker::InitAnyLock(const CallEvent &Call, CheckerContext &C, |
| CheckerKind CheckKind) const { |
| InitLockAux(Call, C, Call.getArgExpr(0), Call.getArgSVal(0), CheckKind); |
| } |
| |
| void PthreadLockChecker::InitLockAux(const CallEvent &Call, CheckerContext &C, |
| const Expr *MtxExpr, SVal MtxVal, |
| CheckerKind CheckKind) const { |
| if (!ChecksEnabled[CheckKind]) |
| return; |
| |
| const MemRegion *LockR = MtxVal.getAsRegion(); |
| if (!LockR) |
| return; |
| |
| ProgramStateRef State = C.getState(); |
| |
| const SymbolRef *sym = State->get<DestroyRetVal>(LockR); |
| if (sym) |
| State = resolvePossiblyDestroyedMutex(State, LockR, sym); |
| |
| const struct LockState *LState = State->get<LockMap>(LockR); |
| if (!LState || LState->isDestroyed()) { |
| State = State->set<LockMap>(LockR, LockState::getUnlocked()); |
| C.addTransition(State); |
| return; |
| } |
| |
| StringRef Message = LState->isLocked() |
| ? "This lock is still being held" |
| : "This lock has already been initialized"; |
| |
| reportBug(C, BT_initlock, MtxExpr, CheckKind, Message); |
| } |
| |
| void PthreadLockChecker::reportBug(CheckerContext &C, |
| std::unique_ptr<BugType> BT[], |
| const Expr *MtxExpr, CheckerKind CheckKind, |
| StringRef Desc) const { |
| ExplodedNode *N = C.generateErrorNode(); |
| if (!N) |
| return; |
| initBugType(CheckKind); |
| auto Report = |
| std::make_unique<PathSensitiveBugReport>(*BT[CheckKind], Desc, N); |
| Report->addRange(MtxExpr->getSourceRange()); |
| C.emitReport(std::move(Report)); |
| } |
| |
| void PthreadLockChecker::checkDeadSymbols(SymbolReaper &SymReaper, |
| CheckerContext &C) const { |
| ProgramStateRef State = C.getState(); |
| |
| for (auto I : State->get<DestroyRetVal>()) { |
| // Once the return value symbol dies, no more checks can be performed |
| // against it. See if the return value was checked before this point. |
| // This would remove the symbol from the map as well. |
| if (SymReaper.isDead(I.second)) |
| State = resolvePossiblyDestroyedMutex(State, I.first, &I.second); |
| } |
| |
| for (auto I : State->get<LockMap>()) { |
| // Stop tracking dead mutex regions as well. |
| if (!SymReaper.isLiveRegion(I.first)) { |
| State = State->remove<LockMap>(I.first); |
| State = State->remove<DestroyRetVal>(I.first); |
| } |
| } |
| |
| // TODO: We probably need to clean up the lock stack as well. |
| // It is tricky though: even if the mutex cannot be unlocked anymore, |
| // it can still participate in lock order reversal resolution. |
| |
| C.addTransition(State); |
| } |
| |
| ProgramStateRef PthreadLockChecker::checkRegionChanges( |
| ProgramStateRef State, const InvalidatedSymbols *Symbols, |
| ArrayRef<const MemRegion *> ExplicitRegions, |
| ArrayRef<const MemRegion *> Regions, const LocationContext *LCtx, |
| const CallEvent *Call) const { |
| |
| bool IsLibraryFunction = false; |
| if (Call && Call->isGlobalCFunction()) { |
| // Avoid invalidating mutex state when a known supported function is called. |
| if (PThreadCallbacks.lookup(*Call) || FuchsiaCallbacks.lookup(*Call) || |
| C11Callbacks.lookup(*Call)) |
| return State; |
| |
| if (Call->isInSystemHeader()) |
| IsLibraryFunction = true; |
| } |
| |
| for (auto R : Regions) { |
| // We assume that system library function wouldn't touch the mutex unless |
| // it takes the mutex explicitly as an argument. |
| // FIXME: This is a bit quadratic. |
| if (IsLibraryFunction && |
| std::find(ExplicitRegions.begin(), ExplicitRegions.end(), R) == |
| ExplicitRegions.end()) |
| continue; |
| |
| State = State->remove<LockMap>(R); |
| State = State->remove<DestroyRetVal>(R); |
| |
| // TODO: We need to invalidate the lock stack as well. This is tricky |
| // to implement correctly and efficiently though, because the effects |
| // of mutex escapes on lock order may be fairly varied. |
| } |
| |
| return State; |
| } |
| |
| void ento::registerPthreadLockBase(CheckerManager &mgr) { |
| mgr.registerChecker<PthreadLockChecker>(); |
| } |
| |
| bool ento::shouldRegisterPthreadLockBase(const CheckerManager &mgr) { return true; } |
| |
| #define REGISTER_CHECKER(name) \ |
| void ento::register##name(CheckerManager &mgr) { \ |
| PthreadLockChecker *checker = mgr.getChecker<PthreadLockChecker>(); \ |
| checker->ChecksEnabled[PthreadLockChecker::CK_##name] = true; \ |
| checker->CheckNames[PthreadLockChecker::CK_##name] = \ |
| mgr.getCurrentCheckerName(); \ |
| } \ |
| \ |
| bool ento::shouldRegister##name(const CheckerManager &mgr) { return true; } |
| |
| REGISTER_CHECKER(PthreadLockChecker) |
| REGISTER_CHECKER(FuchsiaLockChecker) |
| REGISTER_CHECKER(C11LockChecker) |
