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Merge pull request #9666 from liamwhite/wait-for-me

kernel: fix incorrect locking order in suspension
This commit is contained in:
bunnei 2023-01-27 15:06:09 -08:00 committed by GitHub
commit 32b2a72e7b
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6 changed files with 56 additions and 46 deletions

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@ -171,7 +171,7 @@ Result KConditionVariable::WaitForAddress(Handle handle, VAddr addr, u32 value)
R_UNLESS(owner_thread != nullptr, ResultInvalidHandle); R_UNLESS(owner_thread != nullptr, ResultInvalidHandle);
// Update the lock. // Update the lock.
cur_thread->SetAddressKey(addr, value); cur_thread->SetUserAddressKey(addr, value);
owner_thread->AddWaiter(cur_thread); owner_thread->AddWaiter(cur_thread);
// Begin waiting. // Begin waiting.

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@ -68,7 +68,7 @@ bool KLightLock::LockSlowPath(uintptr_t _owner, uintptr_t _cur_thread) {
// Add the current thread as a waiter on the owner. // Add the current thread as a waiter on the owner.
KThread* owner_thread = reinterpret_cast<KThread*>(_owner & ~1ULL); KThread* owner_thread = reinterpret_cast<KThread*>(_owner & ~1ULL);
cur_thread->SetAddressKey(reinterpret_cast<uintptr_t>(std::addressof(tag))); cur_thread->SetKernelAddressKey(reinterpret_cast<uintptr_t>(std::addressof(tag)));
owner_thread->AddWaiter(cur_thread); owner_thread->AddWaiter(cur_thread);
// Begin waiting to hold the lock. // Begin waiting to hold the lock.

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@ -67,9 +67,9 @@ constexpr size_t KernelPageBufferAdditionalSize = 0x33C000;
constexpr std::size_t KernelResourceSize = KernelPageTableHeapSize + KernelInitialPageHeapSize + constexpr std::size_t KernelResourceSize = KernelPageTableHeapSize + KernelInitialPageHeapSize +
KernelSlabHeapSize + KernelPageBufferHeapSize; KernelSlabHeapSize + KernelPageBufferHeapSize;
constexpr bool IsKernelAddressKey(VAddr key) { //! NB: Use KThread::GetAddressKeyIsKernel().
return KernelVirtualAddressSpaceBase <= key && key <= KernelVirtualAddressSpaceLast; //! See explanation for deviation of GetAddressKey.
} bool IsKernelAddressKey(VAddr key) = delete;
constexpr bool IsKernelAddress(VAddr address) { constexpr bool IsKernelAddress(VAddr address) {
return KernelVirtualAddressSpaceBase <= address && address < KernelVirtualAddressSpaceEnd; return KernelVirtualAddressSpaceBase <= address && address < KernelVirtualAddressSpaceEnd;

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@ -330,7 +330,7 @@ void KThread::Finalize() {
KThread* const waiter = std::addressof(*it); KThread* const waiter = std::addressof(*it);
// The thread shouldn't be a kernel waiter. // The thread shouldn't be a kernel waiter.
ASSERT(!IsKernelAddressKey(waiter->GetAddressKey())); ASSERT(!waiter->GetAddressKeyIsKernel());
// Clear the lock owner. // Clear the lock owner.
waiter->SetLockOwner(nullptr); waiter->SetLockOwner(nullptr);
@ -763,19 +763,6 @@ void KThread::Continue() {
KScheduler::OnThreadStateChanged(kernel, this, old_state); KScheduler::OnThreadStateChanged(kernel, this, old_state);
} }
void KThread::WaitUntilSuspended() {
// Make sure we have a suspend requested.
ASSERT(IsSuspendRequested());
// Loop until the thread is not executing on any core.
for (std::size_t i = 0; i < static_cast<std::size_t>(Core::Hardware::NUM_CPU_CORES); ++i) {
KThread* core_thread{};
do {
core_thread = kernel.Scheduler(i).GetSchedulerCurrentThread();
} while (core_thread == this);
}
}
Result KThread::SetActivity(Svc::ThreadActivity activity) { Result KThread::SetActivity(Svc::ThreadActivity activity) {
// Lock ourselves. // Lock ourselves.
KScopedLightLock lk(activity_pause_lock); KScopedLightLock lk(activity_pause_lock);
@ -897,7 +884,7 @@ void KThread::AddWaiterImpl(KThread* thread) {
} }
// Keep track of how many kernel waiters we have. // Keep track of how many kernel waiters we have.
if (IsKernelAddressKey(thread->GetAddressKey())) { if (thread->GetAddressKeyIsKernel()) {
ASSERT((num_kernel_waiters++) >= 0); ASSERT((num_kernel_waiters++) >= 0);
KScheduler::SetSchedulerUpdateNeeded(kernel); KScheduler::SetSchedulerUpdateNeeded(kernel);
} }
@ -911,7 +898,7 @@ void KThread::RemoveWaiterImpl(KThread* thread) {
ASSERT(kernel.GlobalSchedulerContext().IsLocked()); ASSERT(kernel.GlobalSchedulerContext().IsLocked());
// Keep track of how many kernel waiters we have. // Keep track of how many kernel waiters we have.
if (IsKernelAddressKey(thread->GetAddressKey())) { if (thread->GetAddressKeyIsKernel()) {
ASSERT((num_kernel_waiters--) > 0); ASSERT((num_kernel_waiters--) > 0);
KScheduler::SetSchedulerUpdateNeeded(kernel); KScheduler::SetSchedulerUpdateNeeded(kernel);
} }
@ -987,7 +974,7 @@ KThread* KThread::RemoveWaiterByKey(s32* out_num_waiters, VAddr key) {
KThread* thread = std::addressof(*it); KThread* thread = std::addressof(*it);
// Keep track of how many kernel waiters we have. // Keep track of how many kernel waiters we have.
if (IsKernelAddressKey(thread->GetAddressKey())) { if (thread->GetAddressKeyIsKernel()) {
ASSERT((num_kernel_waiters--) > 0); ASSERT((num_kernel_waiters--) > 0);
KScheduler::SetSchedulerUpdateNeeded(kernel); KScheduler::SetSchedulerUpdateNeeded(kernel);
} }

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@ -214,8 +214,6 @@ public:
void Continue(); void Continue();
void WaitUntilSuspended();
constexpr void SetSyncedIndex(s32 index) { constexpr void SetSyncedIndex(s32 index) {
synced_index = index; synced_index = index;
} }
@ -607,13 +605,30 @@ public:
return address_key_value; return address_key_value;
} }
void SetAddressKey(VAddr key) { [[nodiscard]] bool GetAddressKeyIsKernel() const {
address_key = key; return address_key_is_kernel;
} }
void SetAddressKey(VAddr key, u32 val) { //! NB: intentional deviation from official kernel.
//
// Separate SetAddressKey into user and kernel versions
// to cope with arbitrary host pointers making their way
// into things.
void SetUserAddressKey(VAddr key) {
address_key = key;
address_key_is_kernel = false;
}
void SetUserAddressKey(VAddr key, u32 val) {
address_key = key; address_key = key;
address_key_value = val; address_key_value = val;
address_key_is_kernel = false;
}
void SetKernelAddressKey(VAddr key) {
address_key = key;
address_key_is_kernel = true;
} }
void ClearWaitQueue() { void ClearWaitQueue() {
@ -772,6 +787,7 @@ private:
bool debug_attached{}; bool debug_attached{};
s8 priority_inheritance_count{}; s8 priority_inheritance_count{};
bool resource_limit_release_hint{}; bool resource_limit_release_hint{};
bool address_key_is_kernel{};
StackParameters stack_parameters{}; StackParameters stack_parameters{};
Common::SpinLock context_guard{}; Common::SpinLock context_guard{};

View file

@ -1198,27 +1198,34 @@ void KernelCore::Suspend(bool suspended) {
const bool should_suspend{exception_exited || suspended}; const bool should_suspend{exception_exited || suspended};
const auto activity = should_suspend ? ProcessActivity::Paused : ProcessActivity::Runnable; const auto activity = should_suspend ? ProcessActivity::Paused : ProcessActivity::Runnable;
std::vector<KScopedAutoObject<KThread>> process_threads; //! This refers to the application process, not the current process.
{ KScopedAutoObject<KProcess> process = CurrentProcess();
KScopedSchedulerLock sl{*this}; if (process.IsNull()) {
return;
if (auto* process = CurrentProcess(); process != nullptr) {
process->SetActivity(activity);
if (!should_suspend) {
// Runnable now; no need to wait.
return;
}
for (auto* thread : process->GetThreadList()) {
process_threads.emplace_back(thread);
}
}
} }
// Wait for execution to stop. // Set the new activity.
for (auto& thread : process_threads) { process->SetActivity(activity);
thread->WaitUntilSuspended();
// Wait for process execution to stop.
bool must_wait{should_suspend};
// KernelCore::Suspend must be called from locked context, or we
// could race another call to SetActivity, interfering with waiting.
while (must_wait) {
KScopedSchedulerLock sl{*this};
// Assume that all threads have finished running.
must_wait = false;
for (auto i = 0; i < static_cast<s32>(Core::Hardware::NUM_CPU_CORES); ++i) {
if (Scheduler(i).GetSchedulerCurrentThread()->GetOwnerProcess() ==
process.GetPointerUnsafe()) {
// A thread has not finished running yet.
// Continue waiting.
must_wait = true;
}
}
} }
} }