From a648331e2621b6dd8ef4e43c603854e3fcdf163a Mon Sep 17 00:00:00 2001
From: Robin Burchell <robin+git@viroteck.net>
Date: Wed, 17 Jul 2019 14:15:13 +0200
Subject: [PATCH] Kernel: Fix a nasty lock bug with exec()

Exec doesn't leave through the syscall handler, so it didn't unlock the
big_lock. This means that reentering can lock it again, and then another
thread could endlessly yield waiting to acquire the lock (futilely).

This fixes AudioServer using 100% CPU.
---
 Kernel/Process.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Kernel/Process.cpp b/Kernel/Process.cpp
index 7ce78fadd0..0409299eb7 100644
--- a/Kernel/Process.cpp
+++ b/Kernel/Process.cpp
@@ -442,6 +442,7 @@ int Process::do_exec(String path, Vector<String> arguments, Vector<String> envir
 #endif
 
     main_thread().set_state(Thread::State::Skip1SchedulerPass);
+    big_lock().unlock_if_locked();
     return 0;
 }