Only in libthreads: .svn
Common subdirectories: libthreads.orig/alpha and libthreads/alpha
diff -du libthreads.orig/cthreads.h libthreads/cthreads.h
--- libthreads.orig/cthreads.h	2010-05-14 10:14:33.000000000 +0000
+++ libthreads/cthreads.h	2010-05-14 10:22:24.000000000 +0000
@@ -275,6 +275,12 @@
 #define	FALSE	0
 #endif
 
+/* 
+ * Enable mutex holder debugging 
+ */
+
+#define MUTEX_HOLDER_DEBUG
+
 /*
  * C Threads package initialization.
  */
@@ -382,8 +388,8 @@
 	spin_lock_t lock;
 	const char *name;
 	struct cthread_queue queue;
-	/* holder is for WAIT_DEBUG. Not ifdeffed to keep size constant. */
-	struct cthread *holder;
+	/* fname is for WAIT_DEBUG. Not ifdeffed to keep size constant. */
+	void *fname;
 } *mutex_t;
 
 /* Rearranged accordingly for GNU: */
@@ -396,7 +402,7 @@
 	spin_lock_init(&(m)->lock); \
 	cthread_queue_init(&(m)->queue); \
 	spin_lock_init(&(m)->held); \
-	(m)->holder = 0; \
+	(m)->fname = 0; \
 	MACRO_END
 #define	mutex_set_name(m, x)	((m)->name = (x))
 #define	mutex_name(m)		((m)->name != 0 ? (m)->name : "?")
@@ -404,13 +410,13 @@
 #define	mutex_free(m)		free((m))
 
 #define mutex_try_lock(m) spin_try_lock(&(m)->held)
-#if defined(WAIT_DEBUG)
+#if defined(MUTEX_HOLDER_DEBUG)
 #define mutex_lock(m) \
 	MACRO_BEGIN \
 	if (!spin_try_lock(&(m)->held)) { \
 		__mutex_lock_solid(m); \
 	} \
-	(m)->holder = cthread_self(); \
+	(m)->fname = &__FUNCTION__; \
 	MACRO_END
 #define mutex_unlock(m) \
 	MACRO_BEGIN \
@@ -418,9 +424,9 @@
 	    cthread_queue_head(&(m)->queue, vm_offset_t) != 0) { \
 		__mutex_unlock_solid(m); \
 	} \
-	(m)->holder = 0; \
+	(m)->fname = 0; \
 	MACRO_END
-#else /* defined(WAIT_DEBUG */
+#else /* defined(MUTEX_HOLDER_DEBUG) */
 #define mutex_lock(m) \
 	MACRO_BEGIN \
 	if (!spin_try_lock(&(m)->held)) { \
@@ -434,7 +440,7 @@
 		__mutex_unlock_solid(m); \
 	} \
 	MACRO_END
-#endif /* defined(WAIT_DEBUG) */
+#endif /* defined(MUTEX_HOLDER_DEBUG) */
 /*
  * Condition variables.
  */
Common subdirectories: libthreads.orig/i386 and libthreads/i386