CVS commit: src/sys/uvm

[Jaromir Dolecek]

Module Name:    src
Committed By:   jdolecek
Date:           Fri May 25 20:11:03 UTC 2018

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

Log Message:
add the KASSERT() for loan_count wrap-around to all places which increase it


To generate a diff of this commit:
cvs rdiff -u -r1.86 -r1.87 src/sys/uvm/uvm_loan.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_loan.c
diff -u src/sys/uvm/uvm_loan.c:1.86 src/sys/uvm/uvm_loan.c:1.87
--- src/sys/uvm/uvm_loan.c:1.86	Sat May 19 11:02:33 2018
+++ src/sys/uvm/uvm_loan.c	Fri May 25 20:11:03 2018
@@ -1,4 +1,4 @@
-/*	$NetBSD: uvm_loan.c,v 1.86 2018/05/19 11:02:33 jdolecek Exp $	*/
+/*	$NetBSD: uvm_loan.c,v 1.87 2018/05/25 20:11:03 jdolecek Exp $	*/
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_loan.c,v 1.86 2018/05/19 11:02:33 jdolecek Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_loan.c,v 1.87 2018/05/25 20:11:03 jdolecek Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -475,6 +475,7 @@ uvm_loanpage(struct vm_page **pgpp, int 
 			pmap_page_protect(pg, VM_PROT_READ);
 		}
 		pg->loan_count++;
+		KASSERT(pg->loan_count > 0);	/* detect wrap-around */
 		uvm_pageactivate(pg);
 		mutex_exit(&uvm_pageqlock);
 	}
@@ -788,6 +789,7 @@ uvm_loanuobj(struct uvm_faultinfo *ufi, 
 		pmap_page_protect(pg, VM_PROT_READ);
 	}
 	pg->loan_count++;
+	KASSERT(pg->loan_count > 0);	/* detect wrap-around */
 	pg->uanon = anon;
 	anon->an_page = pg;
 	anon->an_lock = /* TODO: share amap lock */
@@ -879,6 +881,7 @@ again:
 	if ((flags & UVM_LOAN_TOANON) == 0) {	/* loaning to kernel-page */
 		mutex_enter(&uvm_pageqlock);
 		pg->loan_count++;
+		KASSERT(pg->loan_count > 0);	/* detect wrap-around */
 		mutex_exit(&uvm_pageqlock);
 		mutex_exit(uvm_loanzero_object.vmobjlock);
 		**output = pg;
@@ -919,6 +922,7 @@ again:
 	pg->uanon = anon;
 	mutex_enter(&uvm_pageqlock);
 	pg->loan_count++;
+	KASSERT(pg->loan_count > 0);	/* detect wrap-around */
 	uvm_pageactivate(pg);
 	mutex_exit(&uvm_pageqlock);
 	mutex_exit(&anon->an_lock);