From c1c12497b56edbdbd02cb3f687a676f1c6a39cac Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Mon, 16 Aug 2021 01:54:34 +0200
Subject: Kernel: Don't hold thread list lock while invoking ~Thread()

There is no need for this, and it can cause deadlocks if ~Thread()
ends up doing something else that requires a lock (e.g ~Process())
---
 Kernel/Thread.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/Kernel/Thread.cpp b/Kernel/Thread.cpp
index 59389476b1..506675abc7 100644
--- a/Kernel/Thread.cpp
+++ b/Kernel/Thread.cpp
@@ -39,13 +39,16 @@ SpinLockProtectedValue<Thread::GlobalList>& Thread::all_threads()
 
 bool Thread::unref() const
 {
-    return all_threads().with([&](auto&) {
+    bool did_hit_zero = all_threads().with([&](auto&) {
         if (deref_base())
             return false;
         m_global_thread_list_node.remove();
-        delete this;
         return true;
     });
+
+    if (did_hit_zero)
+        delete this;
+    return did_hit_zero;
 }
 
 KResultOr<NonnullRefPtr<Thread>> Thread::try_create(NonnullRefPtr<Process> process)
-- 
cgit v1.2.3