| /* |
| * Copyright (C) 2017-2019 Apple Inc. All rights reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * |
| * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY |
| * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR |
| * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY |
| * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "config.h" |
| #include "VMTraps.h" |
| |
| #include "CallFrame.h" |
| #include "CodeBlock.h" |
| #include "CodeBlockSet.h" |
| #include "DFGCommonData.h" |
| #include "ExceptionHelpers.h" |
| #include "HeapInlines.h" |
| #include "JSCPtrTag.h" |
| #include "LLIntPCRanges.h" |
| #include "MachineContext.h" |
| #include "MachineStackMarker.h" |
| #include "MacroAssembler.h" |
| #include "MacroAssemblerCodeRef.h" |
| #include "VM.h" |
| #include "VMInspector.h" |
| #include "Watchdog.h" |
| #include <wtf/ProcessID.h> |
| #include <wtf/ThreadMessage.h> |
| #include <wtf/threads/Signals.h> |
| |
| namespace JSC { |
| |
| ALWAYS_INLINE VM& VMTraps::vm() const |
| { |
| return *bitwise_cast<VM*>(bitwise_cast<uintptr_t>(this) - OBJECT_OFFSETOF(VM, m_traps)); |
| } |
| |
| #if ENABLE(SIGNAL_BASED_VM_TRAPS) |
| |
| struct SignalContext { |
| private: |
| SignalContext(PlatformRegisters& registers, MacroAssemblerCodePtr<PlatformRegistersPCPtrTag> trapPC) |
| : registers(registers) |
| , trapPC(trapPC) |
| , stackPointer(MachineContext::stackPointer(registers)) |
| , framePointer(MachineContext::framePointer(registers)) |
| { } |
| |
| public: |
| static Optional<SignalContext> tryCreate(PlatformRegisters& registers) |
| { |
| auto instructionPointer = MachineContext::instructionPointer(registers); |
| if (!instructionPointer) |
| return WTF::nullopt; |
| return SignalContext(registers, *instructionPointer); |
| } |
| |
| PlatformRegisters& registers; |
| MacroAssemblerCodePtr<PlatformRegistersPCPtrTag> trapPC; |
| void* stackPointer; |
| void* framePointer; |
| }; |
| |
| inline static bool vmIsInactive(VM& vm) |
| { |
| return !vm.entryScope && !vm.ownerThread(); |
| } |
| |
| static bool isSaneFrame(CallFrame* frame, CallFrame* calleeFrame, EntryFrame* entryFrame, StackBounds stackBounds) |
| { |
| if (reinterpret_cast<void*>(frame) >= reinterpret_cast<void*>(entryFrame)) |
| return false; |
| if (calleeFrame >= frame) |
| return false; |
| return stackBounds.contains(frame); |
| } |
| |
| void VMTraps::tryInstallTrapBreakpoints(SignalContext& context, StackBounds stackBounds) |
| { |
| // This must be the initial signal to get the mutator thread's attention. |
| // Let's get the thread to break at invalidation points if needed. |
| VM& vm = this->vm(); |
| void* trapPC = context.trapPC.untaggedExecutableAddress(); |
| // We must ensure we're in JIT/LLint code. If we are, we know a few things: |
| // - The JS thread isn't holding the malloc lock. Therefore, it's safe to malloc below. |
| // - The JS thread isn't holding the CodeBlockSet lock. |
| // If we're not in JIT/LLInt code, we can't run the C++ code below because it |
| // mallocs, and we must prove the JS thread isn't holding the malloc lock |
| // to be able to do that without risking a deadlock. |
| if (!isJITPC(trapPC) && !LLInt::isLLIntPC(trapPC)) |
| return; |
| |
| CallFrame* callFrame = reinterpret_cast<CallFrame*>(context.framePointer); |
| |
| auto codeBlockSetLocker = holdLock(vm.heap.codeBlockSet().getLock()); |
| |
| CodeBlock* foundCodeBlock = nullptr; |
| EntryFrame* entryFrame = vm.topEntryFrame; |
| |
| // We don't have a callee to start with. So, use the end of the stack to keep the |
| // isSaneFrame() checker below happy for the first iteration. It will still check |
| // to ensure that the address is in the stackBounds. |
| CallFrame* calleeFrame = reinterpret_cast<CallFrame*>(stackBounds.end()); |
| |
| if (!entryFrame || !callFrame) |
| return; // Not running JS code. Let the SignalSender try again later. |
| |
| do { |
| if (!isSaneFrame(callFrame, calleeFrame, entryFrame, stackBounds)) |
| return; // Let the SignalSender try again later. |
| |
| CodeBlock* candidateCodeBlock = callFrame->unsafeCodeBlock(); |
| if (candidateCodeBlock && vm.heap.codeBlockSet().contains(codeBlockSetLocker, candidateCodeBlock)) { |
| foundCodeBlock = candidateCodeBlock; |
| break; |
| } |
| |
| calleeFrame = callFrame; |
| callFrame = callFrame->callerFrame(entryFrame); |
| |
| } while (callFrame && entryFrame); |
| |
| if (!foundCodeBlock) { |
| // We may have just entered the frame and the codeBlock pointer is not |
| // initialized yet. Just bail and let the SignalSender try again later. |
| return; |
| } |
| |
| if (JITCode::isOptimizingJIT(foundCodeBlock->jitType())) { |
| auto locker = tryHoldLock(*m_lock); |
| if (!locker) |
| return; // Let the SignalSender try again later. |
| |
| if (!needTrapHandling()) { |
| // Too late. Someone else already handled the trap. |
| return; |
| } |
| |
| if (!foundCodeBlock->hasInstalledVMTrapBreakpoints()) |
| foundCodeBlock->installVMTrapBreakpoints(); |
| return; |
| } |
| } |
| |
| void VMTraps::invalidateCodeBlocksOnStack() |
| { |
| invalidateCodeBlocksOnStack(vm().topCallFrame); |
| } |
| |
| void VMTraps::invalidateCodeBlocksOnStack(ExecState* topCallFrame) |
| { |
| auto codeBlockSetLocker = holdLock(vm().heap.codeBlockSet().getLock()); |
| invalidateCodeBlocksOnStack(codeBlockSetLocker, topCallFrame); |
| } |
| |
| void VMTraps::invalidateCodeBlocksOnStack(Locker<Lock>&, ExecState* topCallFrame) |
| { |
| if (!m_needToInvalidatedCodeBlocks) |
| return; |
| |
| m_needToInvalidatedCodeBlocks = false; |
| |
| EntryFrame* entryFrame = vm().topEntryFrame; |
| CallFrame* callFrame = topCallFrame; |
| |
| if (!entryFrame) |
| return; // Not running JS code. Nothing to invalidate. |
| |
| while (callFrame) { |
| CodeBlock* codeBlock = callFrame->codeBlock(); |
| if (codeBlock && JITCode::isOptimizingJIT(codeBlock->jitType())) |
| codeBlock->jettison(Profiler::JettisonDueToVMTraps); |
| callFrame = callFrame->callerFrame(entryFrame); |
| } |
| } |
| |
| class VMTraps::SignalSender final : public AutomaticThread { |
| public: |
| using Base = AutomaticThread; |
| SignalSender(const AbstractLocker& locker, VM& vm) |
| : Base(locker, vm.traps().m_lock, vm.traps().m_condition.copyRef()) |
| , m_vm(vm) |
| { |
| static std::once_flag once; |
| std::call_once(once, [] { |
| installSignalHandler(Signal::BadAccess, [] (Signal, SigInfo&, PlatformRegisters& registers) -> SignalAction { |
| auto signalContext = SignalContext::tryCreate(registers); |
| if (!signalContext) |
| return SignalAction::NotHandled; |
| |
| void* trapPC = signalContext->trapPC.untaggedExecutableAddress(); |
| if (!isJITPC(trapPC)) |
| return SignalAction::NotHandled; |
| |
| CodeBlock* currentCodeBlock = DFG::codeBlockForVMTrapPC(trapPC); |
| if (!currentCodeBlock) { |
| // Either we trapped for some other reason, e.g. Wasm OOB, or we didn't properly monitor the PC. Regardless, we can't do much now... |
| return SignalAction::NotHandled; |
| } |
| ASSERT(currentCodeBlock->hasInstalledVMTrapBreakpoints()); |
| VM& vm = currentCodeBlock->vm(); |
| |
| // We are in JIT code so it's safe to acquire this lock. |
| auto codeBlockSetLocker = holdLock(vm.heap.codeBlockSet().getLock()); |
| bool sawCurrentCodeBlock = false; |
| vm.heap.forEachCodeBlockIgnoringJITPlans(codeBlockSetLocker, [&] (CodeBlock* codeBlock) { |
| // We want to jettison all code blocks that have vm traps breakpoints, otherwise we could hit them later. |
| if (codeBlock->hasInstalledVMTrapBreakpoints()) { |
| if (currentCodeBlock == codeBlock) |
| sawCurrentCodeBlock = true; |
| |
| codeBlock->jettison(Profiler::JettisonDueToVMTraps); |
| } |
| }); |
| RELEASE_ASSERT(sawCurrentCodeBlock); |
| |
| return SignalAction::Handled; // We've successfully jettisoned the codeBlocks. |
| }); |
| }); |
| } |
| |
| const char* name() const override |
| { |
| return "JSC VMTraps Signal Sender Thread"; |
| } |
| |
| VMTraps& traps() { return m_vm.traps(); } |
| |
| protected: |
| PollResult poll(const AbstractLocker&) override |
| { |
| if (traps().m_isShuttingDown) |
| return PollResult::Stop; |
| |
| if (!traps().needTrapHandling()) |
| return PollResult::Wait; |
| |
| // We know that no trap could have been processed and re-added because we are holding the lock. |
| if (vmIsInactive(m_vm)) |
| return PollResult::Wait; |
| return PollResult::Work; |
| } |
| |
| WorkResult work() override |
| { |
| VM& vm = m_vm; |
| |
| auto optionalOwnerThread = vm.ownerThread(); |
| if (optionalOwnerThread) { |
| sendMessage(*optionalOwnerThread.value().get(), [&] (PlatformRegisters& registers) -> void { |
| auto signalContext = SignalContext::tryCreate(registers); |
| if (!signalContext) |
| return; |
| |
| auto ownerThread = vm.apiLock().ownerThread(); |
| // We can't mess with a thread unless it's the one we suspended. |
| if (!ownerThread || ownerThread != optionalOwnerThread) |
| return; |
| |
| Thread& thread = *ownerThread->get(); |
| vm.traps().tryInstallTrapBreakpoints(*signalContext, thread.stack()); |
| }); |
| } |
| |
| { |
| auto locker = holdLock(*traps().m_lock); |
| if (traps().m_isShuttingDown) |
| return WorkResult::Stop; |
| traps().m_condition->waitFor(*traps().m_lock, 1_ms); |
| } |
| return WorkResult::Continue; |
| } |
| |
| private: |
| |
| VM& m_vm; |
| }; |
| |
| #endif // ENABLE(SIGNAL_BASED_VM_TRAPS) |
| |
| void VMTraps::willDestroyVM() |
| { |
| m_isShuttingDown = true; |
| #if ENABLE(SIGNAL_BASED_VM_TRAPS) |
| if (m_signalSender) { |
| { |
| auto locker = holdLock(*m_lock); |
| if (!m_signalSender->tryStop(locker)) |
| m_condition->notifyAll(locker); |
| } |
| m_signalSender->join(); |
| m_signalSender = nullptr; |
| } |
| #endif |
| } |
| |
| void VMTraps::fireTrap(VMTraps::EventType eventType) |
| { |
| ASSERT(!vm().currentThreadIsHoldingAPILock()); |
| { |
| auto locker = holdLock(*m_lock); |
| ASSERT(!m_isShuttingDown); |
| setTrapForEvent(locker, eventType); |
| m_needToInvalidatedCodeBlocks = true; |
| } |
| |
| #if ENABLE(SIGNAL_BASED_VM_TRAPS) |
| if (!Options::usePollingTraps()) { |
| // sendSignal() can loop until it has confirmation that the mutator thread |
| // has received the trap request. We'll call it from another thread so that |
| // fireTrap() does not block. |
| auto locker = holdLock(*m_lock); |
| if (!m_signalSender) |
| m_signalSender = adoptRef(new SignalSender(locker, vm())); |
| m_condition->notifyAll(locker); |
| } |
| #endif |
| } |
| |
| void VMTraps::handleTraps(ExecState* exec, VMTraps::Mask mask) |
| { |
| VM& vm = this->vm(); |
| auto scope = DECLARE_THROW_SCOPE(vm); |
| |
| { |
| auto codeBlockSetLocker = holdLock(vm.heap.codeBlockSet().getLock()); |
| vm.heap.forEachCodeBlockIgnoringJITPlans(codeBlockSetLocker, [&] (CodeBlock* codeBlock) { |
| // We want to jettison all code blocks that have vm traps breakpoints, otherwise we could hit them later. |
| if (codeBlock->hasInstalledVMTrapBreakpoints()) |
| codeBlock->jettison(Profiler::JettisonDueToVMTraps); |
| }); |
| } |
| |
| ASSERT(needTrapHandling(mask)); |
| while (needTrapHandling(mask)) { |
| auto eventType = takeTopPriorityTrap(mask); |
| switch (eventType) { |
| case NeedDebuggerBreak: |
| dataLog("VM ", RawPointer(&vm), " on pid ", getCurrentProcessID(), " received NeedDebuggerBreak trap\n"); |
| invalidateCodeBlocksOnStack(exec); |
| break; |
| |
| case NeedWatchdogCheck: |
| ASSERT(vm.watchdog()); |
| if (LIKELY(!vm.watchdog()->shouldTerminate(exec))) |
| continue; |
| FALLTHROUGH; |
| |
| case NeedTermination: |
| throwException(exec, scope, createTerminatedExecutionException(&vm)); |
| return; |
| |
| default: |
| RELEASE_ASSERT_NOT_REACHED(); |
| } |
| } |
| } |
| |
| auto VMTraps::takeTopPriorityTrap(VMTraps::Mask mask) -> EventType |
| { |
| auto locker = holdLock(*m_lock); |
| for (int i = 0; i < NumberOfEventTypes; ++i) { |
| EventType eventType = static_cast<EventType>(i); |
| if (hasTrapForEvent(locker, eventType, mask)) { |
| clearTrapForEvent(locker, eventType); |
| return eventType; |
| } |
| } |
| return Invalid; |
| } |
| |
| VMTraps::VMTraps() |
| : m_lock(Box<Lock>::create()) |
| , m_condition(AutomaticThreadCondition::create()) |
| { |
| } |
| |
| VMTraps::~VMTraps() |
| { |
| #if ENABLE(SIGNAL_BASED_VM_TRAPS) |
| ASSERT(!m_signalSender); |
| #endif |
| } |
| |
| } // namespace JSC |
