From ae5d7f542c256f3f1b4c5003d666e8ef850516e9 Mon Sep 17 00:00:00 2001
From: Peter Elliott <pelliott@ualberta.ca>
Date: Sun, 12 Feb 2023 00:49:15 -0700
Subject: [PATCH] Kernel: Change polarity of weak ownership between Inode and
 LocalSocket

There was a bug in which bound Inodes would lose all their references
(because localsocket does not reference them), and they would be
deallocated, and clients would get ECONNREFUSED as a result. now
LocalSocket has a strong reference to inode so that the inode will live
as long as the socket, and Inode has a weak reference to the socket,
because if the socket stops being referenced anywhere it should not be
bound.

This still prevents the reference loop that
220b7dd77905b7d573ded093cf88d2dc51f57c69 was trying to fix.
---
 Kernel/FileSystem/Inode.cpp | 2 +-
 Kernel/FileSystem/Inode.h   | 2 +-
 Kernel/Net/LocalSocket.cpp  | 5 ++---
 Kernel/Net/LocalSocket.h    | 2 +-
 4 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/Kernel/FileSystem/Inode.cpp b/Kernel/FileSystem/Inode.cpp
index e6b8f1ef14..1eea0c0b82 100644
--- a/Kernel/FileSystem/Inode.cpp
+++ b/Kernel/FileSystem/Inode.cpp
@@ -143,7 +143,7 @@ ErrorOr<void> Inode::set_shared_vmobject(Memory::SharedInodeVMObject& vmobject)
 
 LockRefPtr<LocalSocket> Inode::bound_socket() const
 {
-    return m_bound_socket;
+    return m_bound_socket.strong_ref();
 }
 
 bool Inode::bind_socket(LocalSocket& socket)
diff --git a/Kernel/FileSystem/Inode.h b/Kernel/FileSystem/Inode.h
index c954de927a..8a327ff266 100644
--- a/Kernel/FileSystem/Inode.h
+++ b/Kernel/FileSystem/Inode.h
@@ -131,7 +131,7 @@ private:
     FileSystem& m_file_system;
     InodeIndex m_index { 0 };
     LockWeakPtr<Memory::SharedInodeVMObject> m_shared_vmobject;
-    LockRefPtr<LocalSocket> m_bound_socket;
+    LockWeakPtr<LocalSocket> m_bound_socket;
     SpinlockProtected<HashTable<InodeWatcher*>, LockRank::None> m_watchers {};
     bool m_metadata_dirty { false };
     LockRefPtr<FIFO> m_fifo;
diff --git a/Kernel/Net/LocalSocket.cpp b/Kernel/Net/LocalSocket.cpp
index bc4afc01e3..4b55e8bea2 100644
--- a/Kernel/Net/LocalSocket.cpp
+++ b/Kernel/Net/LocalSocket.cpp
@@ -260,9 +260,8 @@ void LocalSocket::detach(OpenFileDescription& description)
         m_accept_side_fd_open = false;
 
         if (m_bound) {
-            auto inode = m_inode.strong_ref();
-            if (inode)
-                inode->unbind_socket();
+            if (m_inode)
+                m_inode->unbind_socket();
         }
     }
 
diff --git a/Kernel/Net/LocalSocket.h b/Kernel/Net/LocalSocket.h
index 91722d72cd..5416bd5373 100644
--- a/Kernel/Net/LocalSocket.h
+++ b/Kernel/Net/LocalSocket.h
@@ -73,7 +73,7 @@ private:
     ErrorOr<void> try_set_path(StringView);
 
     // The inode this socket is bound to.
-    LockWeakPtr<Inode> m_inode;
+    LockRefPtr<Inode> m_inode;
 
     UserID m_prebind_uid { 0 };
     GroupID m_prebind_gid { 0 };