From 798bab85d84b7b2c8da81bd8186a92fcbc3e1d38 Mon Sep 17 00:00:00 2001
From: Taylor R Campbell <riastradh@NetBSD.org>
Date: Mon, 31 Jan 2022 01:22:08 +0000
Subject: [PATCH 31/37] specfs: Assert opencnt is nonzero before decrementing.

---
 sys/miscfs/specfs/spec_vnops.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sys/miscfs/specfs/spec_vnops.c b/sys/miscfs/specfs/spec_vnops.c
index 637bb2b82dbf..34b47f1ae1d4 100644
--- a/sys/miscfs/specfs/spec_vnops.c
+++ b/sys/miscfs/specfs/spec_vnops.c
@@ -940,6 +940,8 @@ spec_open(void *v)
 		KASSERT(sn->sn_opencnt == 1);
 		needclose = true;
 	} else {
+		KASSERT(sd->sd_opencnt);
+		KASSERT(sn->sn_opencnt);
 		sd->sd_opencnt--;
 		sn->sn_opencnt--;
 		if (vp->v_type == VBLK)
@@ -1641,6 +1643,8 @@ spec_close(void *v)
 	 * between open and close can use fd_clone.
 	 */
 	mutex_enter(&device_lock);
+	KASSERT(sn->sn_opencnt);
+	KASSERT(sd->sd_opencnt);
 	sn->sn_opencnt--;
 	count = --sd->sd_opencnt;
 	if (vp->v_type == VBLK) {