Prevent a panic when reboot -q is used by making unveil_removevnode

sane.
ok kettenis@

diff --git a/sys/kern/kern_unveil.c b/sys/kern/kern_unveil.c
index 42dece2..7e7b30f 100644 (file)
--- a/sys/kern/kern_unveil.c
+++ b/sys/kern/kern_unveil.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_unveil.c,v 1.9 2018/07/30 15:16:27 deraadt Exp $ */
+/*     $OpenBSD: kern_unveil.c,v 1.10 2018/08/05 13:59:38 beck Exp $   */
 
 /*
  * Copyright (c) 2017-2018 Bob Beck <beck@openbsd.org>
@@ -717,28 +717,37 @@ void
 unveil_removevnode(struct vnode *vp)
 {
        struct process *pr;
-       int count = 0;
 
        if (vp->v_uvcount == 0)
                return;
+
 #ifdef DEBUG_UNVEIL
-       printf("unveil_removevnode found vnode %p with count %d", vp, vp->v_uvcount);
+       printf("unveil_removevnode found vnode %p with count %d\n",
+           vp, vp->v_uvcount);
 #endif
+       vref(vp); /* make sure it is held till we are done */
+
        LIST_FOREACH(pr, &allprocess, ps_list) {
                struct unveil * uv;
 
-               if ((uv = unveil_lookup(vp, pr->ps_mainproc)) != NULL) {
+               if ((uv = unveil_lookup(vp, pr->ps_mainproc)) != NULL &&
+                   uv->uv_vp != NULL) {
                        uv->uv_vp = NULL;
                        uv->uv_flags = 0;
 #ifdef DEBUG_UNVEIL
-       printf("unveil_removevnode vnode %p now count %d", vp, vp->v_uvcount);
+                       printf("unveil_removevnode vnode %p now count %d\n",
+                           vp, vp->v_uvcount);
 #endif
                        pr->ps_uvshrink = 1;
-                       count++;
+                       if (vp->v_uvcount > 0) {
+                               vrele(vp);
+                               vp->v_uvcount--;
+                       } else
+                               panic("vp %p, v_uvcount of %d should be 0",
+                                   vp, vp->v_uvcount);
                }
        }
-       KASSERT(vp->v_uvcount == count);
+       KASSERT(vp->v_uvcount == 0);
 
-       while (vp->v_uvcount--)
-               vrele(vp);
+       vrele(vp); /* release our ref */
 }