Stop leaking kernel stack guard pages.

ok mpi@, anton@

diff --git a/sys/arch/amd64/amd64/vm_machdep.c b/sys/arch/amd64/amd64/vm_machdep.c
index 5275969..5fa5392 100644 (file)
--- a/sys/arch/amd64/amd64/vm_machdep.c
+++ b/sys/arch/amd64/amd64/vm_machdep.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vm_machdep.c,v 1.48 2024/10/21 18:27:34 kettenis Exp $        */
+/*     $OpenBSD: vm_machdep.c,v 1.49 2024/10/24 17:37:03 kettenis Exp $        */
 /*     $NetBSD: vm_machdep.c,v 1.1 2003/04/26 18:39:33 fvdl Exp $      */
 
 /*-
@@ -135,8 +135,16 @@ cpu_exit(struct proc *p)
 void
 setguardpage(struct proc *p)
 {
-       pmap_kremove((vaddr_t)p->p_addr + PAGE_SIZE, PAGE_SIZE);
+       struct vm_page *pg = NULL;
+       vaddr_t va = (vaddr_t)p->p_addr + PAGE_SIZE;
+       paddr_t pa;
+
+       if (pmap_extract(pmap_kernel(), va, &pa))
+               pg = PHYS_TO_VM_PAGE(pa);
+       pmap_kremove(va, PAGE_SIZE);
        pmap_update(pmap_kernel());
+       if (pg)
+               uvm_pagefree(pg);
 }
 
 struct kmem_va_mode kv_physwait = {