diff --git a/sys/geom/geom_vfs.c b/sys/geom/geom_vfs.c
--- a/sys/geom/geom_vfs.c
+++ b/sys/geom/geom_vfs.c
@@ -124,12 +124,12 @@
 			mp = cdevp->si_mountpt;
 		if (mp != NULL) {
 			if (bp->b_iocmd == BIO_READ) {
-				if (LK_HOLDER(bp->b_lock.lk_lock) == LK_KERNPROC)
+				if (BUF_DISOWNED(bp))
 					mp->mnt_stat.f_asyncreads++;
 				else
 					mp->mnt_stat.f_syncreads++;
 			} else if (bp->b_iocmd == BIO_WRITE) {
-				if (LK_HOLDER(bp->b_lock.lk_lock) == LK_KERNPROC)
+				if (BUF_DISOWNED(bp))
 					mp->mnt_stat.f_asyncwrites++;
 				else
 					mp->mnt_stat.f_syncwrites++;
diff --git a/sys/sys/buf.h b/sys/sys/buf.h
--- a/sys/sys/buf.h
+++ b/sys/sys/buf.h
@@ -341,6 +341,13 @@
  */
 #define	BUF_ISLOCKED(bp)						\
 	lockstatus(&(bp)->b_lock)
+
+/*
+ * Check if a buffer lock is currently held by LK_KERNPROC.
+ */
+#define	BUF_DISOWNED(bp)						\
+	lockmgr_disowned(&(bp)->b_lock)
+
 /*
  * Free a buffer lock.
  */