From dc2b8faba2185d94a9520c44c95544fc30fef457 Mon Sep 17 00:00:00 2001
From: Ingo Weinhold <ingo_weinhold@gmx.de>
Date: Tue, 14 Jun 2011 12:48:06 +0000
Subject: [PATCH] exit_debugger(): Only try to release the semaphore when no
 one holds the scheduler lock. Otherwise we may deadlock.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@42182 a95241bf-73f2-0310-859d-f6bbb57e9c96
---
 .../kernel/debugger/invalidate_on_exit/Jamfile       |  4 ++--
 .../invalidate_on_exit/invalidate_on_exit.cpp        | 12 ++++++++++++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/add-ons/kernel/debugger/invalidate_on_exit/Jamfile b/src/add-ons/kernel/debugger/invalidate_on_exit/Jamfile
index f85c86dde6..ef5c955255 100644
--- a/src/add-ons/kernel/debugger/invalidate_on_exit/Jamfile
+++ b/src/add-ons/kernel/debugger/invalidate_on_exit/Jamfile
@@ -1,7 +1,7 @@
 SubDir HAIKU_TOP src add-ons kernel debugger invalidate_on_exit ;
 
-UsePrivateHeaders kernel ;
+UsePrivateKernelHeaders ;
 
 KernelAddon <kdebug>invalidate_on_exit :
 	invalidate_on_exit.cpp
-	;
+;
diff --git a/src/add-ons/kernel/debugger/invalidate_on_exit/invalidate_on_exit.cpp b/src/add-ons/kernel/debugger/invalidate_on_exit/invalidate_on_exit.cpp
index 189247c348..3ff72b3842 100644
--- a/src/add-ons/kernel/debugger/invalidate_on_exit/invalidate_on_exit.cpp
+++ b/src/add-ons/kernel/debugger/invalidate_on_exit/invalidate_on_exit.cpp
@@ -2,9 +2,15 @@
  * Copyright 2008, Michael Lotz, mmlr@mlotz.ch
  * Distributed under the terms of the MIT License.
  */
+
+
 #include <debug.h>
+
 #include <signal.h>
 
+#include <kscheduler.h>
+#include <smp.h>
+
 
 static sem_id sRequestSem = -1;
 
@@ -33,6 +39,12 @@ invalidate_loop(void *data)
 static void
 exit_debugger()
 {
+	// If someone holds the scheduler lock at this point, release_sem_etc()
+	// will block forever. So avoid that.
+	if (!try_acquire_spinlock(&gSchedulerLock))
+		return;
+	release_spinlock(&gSchedulerLock);
+
 	release_sem_etc(sRequestSem, 1, B_DO_NOT_RESCHEDULE);
 }