diff --git a/core/libs/prx/libkernel/Time/TimedWait.cpp b/core/libs/prx/libkernel/Time/TimedWait.cpp
index fd8813901..f5949d6da 100644
--- a/core/libs/prx/libkernel/Time/TimedWait.cpp
+++ b/core/libs/prx/libkernel/Time/TimedWait.cpp
@@ -94,9 +94,12 @@ struct Waiter {
     HANDLE timer = CreateHighResolutionTimer();
     Waiter* previous = nullptr;
     Waiter* next = nullptr;
+    Waiter* nested = nullptr;
     bool queued = false;
+    bool busy = false;
 
     ~Waiter() {
+        delete nested;
         if (event) CloseHandle(event);
         if (timer) CloseHandle(timer);
     }
@@ -118,6 +121,16 @@ Waiter* ThisThreadWaiter() {
     return waiter;
 }
 
+Waiter* AcquireWaiter() {
+    Waiter* waiter = ThisThreadWaiter();
+    while (waiter->busy) {
+        if (!waiter->nested) waiter->nested = new Waiter();
+        waiter = waiter->nested;
+    }
+    waiter->busy = true;
+    return waiter;
+}
+
 bool EventSet(HANDLE event, DWORD milliseconds) {
     return AlertableWait(1, &event, milliseconds) == WAIT_OBJECT_0;
 }
@@ -147,7 +160,7 @@ bool WaitEventUntil(Waiter* waiter, std::uint64_t deadlineNanos) {
 }  // namespace
 
 Waiter* Condition::enqueue() {
-    Waiter* waiter = ThisThreadWaiter();
+    Waiter* waiter = AcquireWaiter();
     std::lock_guard lock(queueLock);
     waiter->queued = true;
     waiter->next = nullptr;
@@ -170,17 +183,22 @@ void Condition::unlink(Waiter* waiter) {
 
 void Condition::waitSignal(Waiter* waiter) {
     AlertableWait(1, &waiter->event, INFINITE);
+    waiter->busy = false;
 }
 
 bool Condition::waitSignalUntil(Waiter* waiter, std::uint64_t deadlineNanos) {
-    if (WaitEventUntil(waiter, deadlineNanos)) return true;
-    std::lock_guard lock(queueLock);
-    if (waiter->queued) {
-        unlink(waiter);
-        return false;
+    bool signaled = WaitEventUntil(waiter, deadlineNanos);
+    if (!signaled) {
+        std::lock_guard lock(queueLock);
+        if (waiter->queued) {
+            unlink(waiter);
+        } else {
+            WaitForSingleObject(waiter->event, 0);
+            signaled = true;
+        }
     }
-    WaitForSingleObject(waiter->event, 0);
-    return true;
+    waiter->busy = false;
+    return signaled;
 }
 
 void Condition::NotifyOne() {
diff --git a/core/libs/tests/GuestRaiseException.cpp b/core/libs/tests/GuestRaiseException.cpp
index aa715601e..7af034edf 100644
--- a/core/libs/tests/GuestRaiseException.cpp
+++ b/core/libs/tests/GuestRaiseException.cpp
@@ -19,10 +19,12 @@ int APS5_VABI sceKernelCreateSema(KernelSema* sem, const char* name, uint32_t at
 int APS5_VABI sceKernelDeleteSema(KernelSema sem);
 int APS5_VABI sceKernelSignalSema(KernelSema sem, int count);
 int APS5_VABI sceKernelWaitSema(KernelSema sem, int need, KernelUseconds* time);
+int APS5_VABI sceKernelSyncOnAddressWait(std::uint32_t* address, std::uint32_t expected, const KernelUseconds* timeout, const char* name);
 }
 
 static constexpr int SCE_KERNEL_ERROR_EINVAL = static_cast<int>(0x80020016);
 static constexpr int SCE_KERNEL_ERROR_ESRCH = static_cast<int>(0x80020003);
+static constexpr int SCE_KERNEL_ERROR_ETIMEDOUT = static_cast<int>(0x8002003c);
 static constexpr int SIGUSR1 = 30;
 static constexpr int Repeats = 100;
 
@@ -109,6 +111,94 @@ static void* APS5_VABI Finished(void*) {
     return nullptr;
 }
 
+static std::uint32_t nestedWord = 0;
+static KernelUseconds nestedTimeout = 0;
+static std::atomic<bool> nestedEntered{false};
+static std::atomic<int> nestedResult{0};
+static std::atomic<int> nestedCalls{0};
+
+static void APS5_VABI NestedHandler(int signum, void*) {
+    Require(signum == SIGUSR1);
+    nestedEntered.store(true);
+    KernelUseconds timeout = nestedTimeout;
+    nestedResult.store(sceKernelSyncOnAddressWait(&nestedWord, 0, &timeout, "nested"));
+    nestedCalls.fetch_add(1);
+}
+
+struct SemaWaiter {
+    KernelSema sem = nullptr;
+    std::atomic<bool> started{false};
+    std::atomic<bool> returned{false};
+    int result = -1;
+};
+
+static void* APS5_VABI WaitSemaOnce(void* arg) {
+    auto& waiter = *static_cast<SemaWaiter*>(arg);
+    waiter.started.store(true);
+    waiter.result = sceKernelWaitSema(waiter.sem, 1, nullptr);
+    waiter.returned.store(true);
+    return nullptr;
+}
+
+static void StartSemaWaiter(Pthread* thread, SemaWaiter& waiter, KernelSema sem, const char* name) {
+    waiter.sem = sem;
+    Require(scePthreadCreate(thread, nullptr, WaitSemaOnce, &waiter, name) == 0);
+    while (!waiter.started.load()) std::this_thread::yield();
+    std::this_thread::sleep_for(std::chrono::milliseconds(50));
+}
+
+static void ExpectReturned(SemaWaiter& waiter) {
+    for (int attempt = 0; attempt < 5000 && !waiter.returned.load(); ++attempt) std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    Require(waiter.returned.load());
+    Require(waiter.result == 0);
+}
+
+static void ExpectNestedDone(int before) {
+    for (int attempt = 0; attempt < 5000 && nestedCalls.load() == before; ++attempt) std::this_thread::sleep_for(std::chrono::milliseconds(1));
+    Require(nestedCalls.load() == before + 1);
+    Require(nestedResult.load() == SCE_KERNEL_ERROR_ETIMEDOUT);
+}
+
+static void NestedWaitKeepsLaterWaiters() {
+    KernelSema sem = nullptr;
+    Require(sceKernelCreateSema(&sem, "nested later", 0, 0, 2, nullptr) == 0);
+    SemaWaiter first;
+    SemaWaiter second;
+    Pthread firstThread = nullptr;
+    Pthread secondThread = nullptr;
+    StartSemaWaiter(&firstThread, first, sem, "nested first");
+    StartSemaWaiter(&secondThread, second, sem, "nested second");
+    nestedTimeout = 20000;
+    const int before = nestedCalls.load();
+    Require(sceKernelRaiseException(firstThread, SIGUSR1) == 0);
+    ExpectNestedDone(before);
+    Require(sceKernelSignalSema(sem, 2) == 0);
+    ExpectReturned(first);
+    ExpectReturned(second);
+    Require(scePthreadJoin(firstThread, nullptr) == 0);
+    Require(scePthreadJoin(secondThread, nullptr) == 0);
+    Require(sceKernelDeleteSema(sem) == 0);
+}
+
+static void NestedWaitKeepsOuterWake() {
+    KernelSema sem = nullptr;
+    Require(sceKernelCreateSema(&sem, "nested outer", 0, 0, 1, nullptr) == 0);
+    SemaWaiter waiter;
+    Pthread thread = nullptr;
+    StartSemaWaiter(&thread, waiter, sem, "nested outer");
+    nestedTimeout = 1000000;
+    nestedEntered.store(false);
+    const int before = nestedCalls.load();
+    Require(sceKernelRaiseException(thread, SIGUSR1) == 0);
+    while (!nestedEntered.load()) std::this_thread::yield();
+    std::this_thread::sleep_for(std::chrono::milliseconds(50));
+    Require(sceKernelSignalSema(sem, 1) == 0);
+    ExpectNestedDone(before);
+    ExpectReturned(waiter);
+    Require(scePthreadJoin(thread, nullptr) == 0);
+    Require(sceKernelDeleteSema(sem) == 0);
+}
+
 static void ExpectDelivery(int before, std::thread::id thread) {
     for (int attempt = 0; attempt < 5000 && calls.load() == before; ++attempt) std::this_thread::sleep_for(std::chrono::milliseconds(1));
     Require(calls.load() == before + 1);
@@ -199,4 +289,9 @@ int main() {
     Require(scePthreadJoin(finishedThread, nullptr) == 0);
 
     Require(sceKernelRemoveExceptionHandler(SIGUSR1) == 0);
+
+    Require(sceKernelInstallExceptionHandler(SIGUSR1, reinterpret_cast<void*>(&NestedHandler)) == 0);
+    NestedWaitKeepsLaterWaiters();
+    NestedWaitKeepsOuterWake();
+    Require(sceKernelRemoveExceptionHandler(SIGUSR1) == 0);
 }