From d72191ed5f276c5b1f01019d4f75fb669817618c Mon Sep 17 00:00:00 2001
From: misson20000 <xenotoad@xenotoad.net>
Date: Fri, 13 Dec 2019 12:58:28 -0800
Subject: [PATCH] pm: fix busy loop on <5.0.0 when processes exit

This was caused by failing to unlink exited processes from the
waitable list, so the process manager thread would loop forever on the
same process signal.
---
 stratosphere/pm/source/impl/pm_process_info.cpp    |  2 +-
 stratosphere/pm/source/impl/pm_process_info.hpp    | 10 ++++++++++
 stratosphere/pm/source/impl/pm_process_manager.cpp |  3 +++
 3 files changed, 14 insertions(+), 1 deletion(-)

diff --git a/stratosphere/pm/source/impl/pm_process_info.cpp b/stratosphere/pm/source/impl/pm_process_info.cpp
index 7bc21b720..161a5cc63 100644
--- a/stratosphere/pm/source/impl/pm_process_info.cpp
+++ b/stratosphere/pm/source/impl/pm_process_info.cpp
@@ -37,7 +37,7 @@ namespace ams::pm::impl {
             this->handle = INVALID_HANDLE;
 
             /* Unlink the process from its waitable manager. */
-            this->waitable_holder.UnlinkFromWaitableManager();
+            UnlinkFromWaitableManagerIfLinked();
         }
     }
 
diff --git a/stratosphere/pm/source/impl/pm_process_info.hpp b/stratosphere/pm/source/impl/pm_process_info.hpp
index 8c15a9964..f0b4648bb 100644
--- a/stratosphere/pm/source/impl/pm_process_info.hpp
+++ b/stratosphere/pm/source/impl/pm_process_info.hpp
@@ -46,6 +46,7 @@ namespace ams::pm::impl {
             ProcessState state;
             u32 flags;
             os::WaitableHolder waitable_holder;
+            bool waitable_holder_is_linked = false;
         private:
             void SetFlag(Flag flag) {
                 this->flags |= flag;
@@ -64,7 +65,16 @@ namespace ams::pm::impl {
             void Cleanup();
 
             void LinkToWaitableManager(os::WaitableManager &manager) {
+                AMS_ASSERT(!waitable_holder_is_linked);
                 manager.LinkWaitableHolder(&this->waitable_holder);
+                waitable_holder_is_linked = true;
+            }
+
+            void UnlinkFromWaitableManagerIfLinked() {
+                if (waitable_holder_is_linked) {
+                    this->waitable_holder.UnlinkFromWaitableManager();
+                    waitable_holder_is_linked = false;
+                }
             }
 
             Handle GetHandle() const {
diff --git a/stratosphere/pm/source/impl/pm_process_manager.cpp b/stratosphere/pm/source/impl/pm_process_manager.cpp
index fecb1236a..ca606c68b 100644
--- a/stratosphere/pm/source/impl/pm_process_manager.cpp
+++ b/stratosphere/pm/source/impl/pm_process_manager.cpp
@@ -414,6 +414,8 @@ namespace ams::pm::impl {
                 case ProcessState_Exited:
                     if (hos::GetVersion() < hos::Version_500 && process_info->ShouldSignalOnExit()) {
                         g_process_event.Signal();
+
+                        process_info->UnlinkFromWaitableManagerIfLinked();
                     } else {
                         /* Free process resources, unlink from waitable manager. */
                         process_info->Cleanup();
@@ -436,6 +438,7 @@ namespace ams::pm::impl {
                             CleanupProcessInfo(list, process_info);
                         }
                     }
+                    break;
                 case ProcessState_DebugSuspended:
                     if (process_info->ShouldSignalOnDebugEvent()) {
                         process_info->SetSuspended();