diff --git a/winsup/cygserver/bsd_mutex.cc b/winsup/cygserver/bsd_mutex.cc
index b95692ba9..d546a610c 100644
--- a/winsup/cygserver/bsd_mutex.cc
+++ b/winsup/cygserver/bsd_mutex.cc
@@ -46,7 +46,7 @@ _mtx_lock (mtx *m, DWORD winpid, const char *file, int line)
     _panic (file, line, "wait for %s in %d failed, %u", m->name, winpid,
 	    GetLastError ());
   m->owner = winpid;
-  _log (file, line, LOG_DEBUG, "Locked      mutex %s/%u (%u)",
+  _log (file, line, LOG_DEBUG, "Locked      mutex %s/%u (owner: %u)",
 	m->name, ++m->cnt, winpid);
 }
 
diff --git a/winsup/cygserver/bsd_mutex.h b/winsup/cygserver/bsd_mutex.h
index cb0cf22b9..9ac970bf0 100644
--- a/winsup/cygserver/bsd_mutex.h
+++ b/winsup/cygserver/bsd_mutex.h
@@ -36,10 +36,10 @@ enum ipc_type {
 extern struct mtx Giant;
 
 void mtx_init (mtx *, const char *, const void *, int);
-void _mtx_lock (mtx *, DWORD winpid, const char *, int);
+void _mtx_lock (mtx *, DWORD, const char *, int);
 #define mtx_lock(m) _mtx_lock((m), (td->ipcblk->winpid), __FILE__, __LINE__)
 int mtx_owned (mtx *, DWORD);
-void _mtx_assert(mtx *, int, DWORD winpid, const char *, int);
+void _mtx_assert(mtx *, int, DWORD, const char *, int);
 #define mtx_assert(m,w,p) _mtx_assert((m),(w),(p),__FILE__,__LINE__)
 void _mtx_unlock (mtx *, const char *, int);
 #define mtx_unlock(m) _mtx_unlock((m),__FILE__,__LINE__)