CVS commit: src/sys/uvm

[Michael van Elst]

Module Name:    src
Committed By:   mlelstv
Date:           Sun Dec  6 08:53:22 UTC 2015

Modified Files:
        src/sys/uvm: uvm_vnode.c

Log Message:
Clean up assertions and catch integer overflow.


To generate a diff of this commit:
cvs rdiff -u -r1.100 -r1.101 src/sys/uvm/uvm_vnode.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.


Modified files:

Index: src/sys/uvm/uvm_vnode.c
diff -u src/sys/uvm/uvm_vnode.c:1.100 src/sys/uvm/uvm_vnode.c:1.101
--- src/sys/uvm/uvm_vnode.c:1.100	Mon Aug 24 22:50:32 2015
+++ src/sys/uvm/uvm_vnode.c	Sun Dec  6 08:53:22 2015
@@ -1,4 +1,4 @@
-/*	$NetBSD: uvm_vnode.c,v 1.100 2015/08/24 22:50:32 pooka Exp $	*/
+/*	$NetBSD: uvm_vnode.c,v 1.101 2015/12/06 08:53:22 mlelstv Exp $	*/
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -45,7 +45,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_vnode.c,v 1.100 2015/08/24 22:50:32 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_vnode.c,v 1.101 2015/12/06 08:53:22 mlelstv Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_uvmhist.h"
@@ -348,15 +348,19 @@ uvm_vnp_setsize(struct vnode *vp, voff_t
 	 * toss some pages...
 	 */
 
-	KASSERT(newsize != VSIZENOTSET);
+	KASSERT(newsize != VSIZENOTSET && newsize >= 0);
 	KASSERT(vp->v_size <= vp->v_writesize);
 	KASSERT(vp->v_size == vp->v_writesize ||
 	    newsize == vp->v_writesize || newsize <= vp->v_size);
 
 	oldsize = vp->v_writesize;
-	KASSERT(oldsize != VSIZENOTSET || pgend > oldsize);
 
-	if (oldsize > pgend) {
+	/*
+	 * check wether size shrinks
+	 * if old size hasn't been set, there are no pages to drop
+	 * if there was an integer overflow in pgend, then this is no shrink
+	 */
+	if (oldsize > pgend && oldsize != VSIZENOTSET && pgend >= 0) {
 		(void) uvn_put(uobj, pgend, 0, PGO_FREE | PGO_SYNCIO);
 		mutex_enter(uobj->vmobjlock);
 	}
@@ -369,7 +373,7 @@ uvm_vnp_setwritesize(struct vnode *vp, v
 {
 
 	mutex_enter(vp->v_interlock);
-	KASSERT(newsize != VSIZENOTSET);
+	KASSERT(newsize != VSIZENOTSET && newsize >= 0);
 	KASSERT(vp->v_size != VSIZENOTSET);
 	KASSERT(vp->v_writesize != VSIZENOTSET);
 	KASSERT(vp->v_size <= vp->v_writesize);