kernel reenter patch

diff --git a/repos/base-hw/src/core/include/kernel/lock.h b/repos/base-hw/src/core/include/kernel/lock.h
index de49428..3564058 100644
--- a/repos/base-hw/src/core/include/kernel/lock.h
+++ b/repos/base-hw/src/core/include/kernel/lock.h
@@ -19,6 +19,7 @@
 #include <base/lock_guard.h>
 #include <cpu/atomic.h>
 #include <cpu/memory_barrier.h>
+#include <cpu.h>

 namespace Kernel
 {
@@ -43,7 +44,17 @@ class Kernel::Lock
        /**
         * Request the lock
         */
-       void lock() { while (!Genode::cmpxchg(&_locked, 0, 1)); }
+       void lock()
+       {
+           if (!Genode::cmpxchg(&_locked, 0, 1)) {
+               PERR("An exception was raised during kernel execution!");
+               PERR("DFSR=%p IFSR=%p DFAR=%p",
+                    (void*)Genode::Cpu::Dfsr::read(),
+                    (void*)Genode::Cpu::Ifsr::read(),
+                    (void*)Genode::Cpu::Dfar::read());
+               while (true) ;
+           }
+       }

        /**
         * Free the lock