mtxleak.patch

diff --git a/include/sys/mutex.h b/include/sys/mutex.h
index 3192352..bccc61b 100644
--- a/include/sys/mutex.h
+++ b/include/sys/mutex.h
@@ -47,8 +47,24 @@ typedef struct {
 #ifdef CONFIG_LOCKDEP
 	kmutex_type_t		m_type;
 #endif /* CONFIG_LOCKDEP */
+#ifdef CONFIG_DEBUG_KMEMLEAK
+	void			*leak;
+#endif
 } kmutex_t;
 
+#ifdef CONFIG_DEBUG_KMEMLEAK
+void kfree(const void *);
+void spl_mutex_leak_init(kmutex_t *, const char *);
+static inline void spl_mutex_leak_fini(kmutex_t *mp)
+{
+	kfree(mp->leak);
+	mp->leak = NULL;
+}
+#else
+#define	spl_mutex_leak_init(mp, name)	do { } while (0)
+#define	spl_mutex_leak_fini(mp)		do { } while (0)
+#endif
+
 #define	MUTEX(mp)		(&((mp)->m_mutex))
 
 static inline void
@@ -120,12 +136,14 @@ spl_mutex_lockdep_on_maybe(kmutex_t *mp)			\
 	spin_lock_init(&(mp)->m_lock);				\
 	spl_mutex_clear_owner(mp);				\
 	spl_mutex_set_type(mp, type);				\
+	spl_mutex_leak_init(mp, #mp);				\
 }
 
 #undef mutex_destroy
 #define	mutex_destroy(mp)					\
 {								\
 	VERIFY3P(mutex_owner(mp), ==, NULL);			\
+	spl_mutex_leak_fini(mp);				\
 }
 
 #define	mutex_tryenter(mp)					\
diff --git a/module/spl/spl-mutex.c b/module/spl/spl-mutex.c
index a29d488..eb7efd1 100644
--- a/module/spl/spl-mutex.c
+++ b/module/spl/spl-mutex.c
@@ -24,6 +24,7 @@
  *  Solaris Porting Layer (SPL) Mutex Implementation.
 \*****************************************************************************/
 
+#include <linux/slab.h>
 #include <sys/mutex.h>
 
 #ifdef DEBUG_SUBSYSTEM
@@ -32,5 +33,15 @@
 
 #define DEBUG_SUBSYSTEM S_MUTEX
 
+#ifdef CONFIG_DEBUG_KMEMLEAK
+void spl_mutex_leak_init(kmutex_t *mp, const char *name)
+{
+	mp->leak = kmalloc(16, GFP_KERNEL);
+	/* No, we don't care about the '\0'. */
+	strncpy(mp->leak, name, 16);
+}
+EXPORT_SYMBOL(spl_mutex_leak_init);
+#endif
+
 int spl_mutex_init(void) { return 0; }
 void spl_mutex_fini(void) { }