Add sanity checks in uvm_pagelookup().

ok kettenis@

diff --git a/sys/uvm/uvm_page.c b/sys/uvm/uvm_page.c
index bab50a8..774345a 100644 (file)
--- a/sys/uvm/uvm_page.c
+++ b/sys/uvm/uvm_page.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: uvm_page.c,v 1.172 2023/05/13 09:24:59 mpi Exp $      */
+/*     $OpenBSD: uvm_page.c,v 1.173 2023/08/12 07:22:56 mpi Exp $      */
 /*     $NetBSD: uvm_page.c,v 1.44 2000/11/27 08:40:04 chs Exp $        */
 
 /*
@@ -1219,10 +1219,15 @@ struct vm_page *
 uvm_pagelookup(struct uvm_object *obj, voff_t off)
 {
        /* XXX if stack is too much, handroll */
-       struct vm_page pg;
+       struct vm_page p, *pg;
 
-       pg.offset = off;
-       return RBT_FIND(uvm_objtree, &obj->memt, &pg);
+       p.offset = off;
+       pg = RBT_FIND(uvm_objtree, &obj->memt, &p);
+
+       KASSERT(pg == NULL || obj->uo_npages != 0);
+       KASSERT(pg == NULL || (pg->pg_flags & PG_RELEASED) == 0 ||
+           (pg->pg_flags & PG_BUSY) != 0);
+       return (pg);
 }
 
 /*