From 90c49befd4e918d5a5f7638c23f836844ae065b1 Mon Sep 17 00:00:00 2001
From: "Unknown W. Brackets" <checkins@unknownbrackets.org>
Date: Sat, 12 Oct 2013 02:08:00 -0700
Subject: [PATCH] Fix a possible race on shutdown.

---
 Core/MIPS/MIPSDebugInterface.cpp |  2 +-
 Core/System.cpp                  | 21 +++++++++++++--------
 2 files changed, 14 insertions(+), 9 deletions(-)

diff --git a/Core/MIPS/MIPSDebugInterface.cpp b/Core/MIPS/MIPSDebugInterface.cpp
index ea55ab2ced..d8e5962e35 100644
--- a/Core/MIPS/MIPSDebugInterface.cpp
+++ b/Core/MIPS/MIPSDebugInterface.cpp
@@ -126,7 +126,7 @@ unsigned int MIPSDebugInterface::readMemory(unsigned int address)
 
 bool MIPSDebugInterface::isAlive()
 {
-	return PSP_IsInited();
+	return PSP_IsInited() && coreState != CORE_ERROR && coreState != CORE_POWERDOWN;
 }
 
 bool MIPSDebugInterface::isBreakpoint(unsigned int address) 
diff --git a/Core/System.cpp b/Core/System.cpp
index ca39a6b6a1..125114ecef 100644
--- a/Core/System.cpp
+++ b/Core/System.cpp
@@ -67,6 +67,7 @@ static PSPMixer *mixer;
 static std::thread *cpuThread = NULL;
 static recursive_mutex cpuThreadLock;
 static condition_variable cpuThreadCond;
+static condition_variable cpuThreadReplyCond;
 static u64 cpuThreadUntil;
 
 // This can be read and written from ANYWHERE.
@@ -95,9 +96,11 @@ bool IsOnSeparateCPUThread() {
 }
 
 bool CPU_NextState(CPUThreadState from, CPUThreadState to) {
+	lock_guard guard(cpuThreadLock);
 	if (cpuThreadState == from) {
 		cpuThreadState = to;
 		cpuThreadCond.notify_one();
+		cpuThreadReplyCond.notify_one();
 		return true;
 	} else {
 		return false;
@@ -105,8 +108,10 @@ bool CPU_NextState(CPUThreadState from, CPUThreadState to) {
 }
 
 void CPU_SetState(CPUThreadState to) {
+	lock_guard guard(cpuThreadLock);
 	cpuThreadState = to;
 	cpuThreadCond.notify_one();
+	cpuThreadReplyCond.notify_one();
 }
 
 bool CPU_IsReady() {
@@ -121,11 +126,11 @@ bool CPU_HasPendingAction() {
 	return cpuThreadState != CPU_THREAD_RUNNING;
 }
 
-void CPU_WaitStatus(bool (*pred)()) {
-	cpuThreadLock.lock();
-	while (!pred())
-		cpuThreadCond.wait(cpuThreadLock);
-	cpuThreadLock.unlock();
+void CPU_WaitStatus(condition_variable &cond, bool (*pred)()) {
+	lock_guard guard(cpuThreadLock);
+	while (!pred()) {
+		cond.wait(cpuThreadLock);
+	}
 }
 
 void CPU_Shutdown();
@@ -219,7 +224,7 @@ void CPU_RunLoop() {
 
 	while (cpuThreadState != CPU_THREAD_SHUTDOWN)
 	{
-		CPU_WaitStatus(&CPU_HasPendingAction);
+		CPU_WaitStatus(cpuThreadCond, &CPU_HasPendingAction);
 		switch (cpuThreadState) {
 		case CPU_THREAD_EXECUTE:
 			mipsr4k.RunLoopUntil(cpuThreadUntil);
@@ -271,7 +276,7 @@ bool PSP_Init(const CoreParameter &coreParam, std::string *error_string) {
 		Core_ListenShutdown(System_Wake);
 		CPU_SetState(CPU_THREAD_PENDING);
 		cpuThread = new std::thread(&CPU_RunLoop);
-		CPU_WaitStatus(&CPU_IsReady);
+		CPU_WaitStatus(cpuThreadReplyCond, &CPU_IsReady);
 	} else {
 		CPU_Init();
 	}
@@ -298,7 +303,7 @@ void PSP_Shutdown() {
 	Core_NotifyShutdown();
 	if (cpuThread != NULL) {
 		CPU_SetState(CPU_THREAD_SHUTDOWN);
-		CPU_WaitStatus(&CPU_IsShutdown);
+		CPU_WaitStatus(cpuThreadReplyCond, &CPU_IsShutdown);
 		delete cpuThread;
 		cpuThread = 0;
 	} else {