CVS commit: src/sys

[Juergen Hannken-Illjes]

Module Name:    src
Committed By:   hannken
Date:           Tue Nov 30 10:55:26 UTC 2010

Modified Files:
        src/sys/miscfs/genfs: genfs_io.c
        src/sys/uvm: uvm_bio.c

Log Message:
Always take the object lock before changing vmpage flags.  Fixes a deadlock
where a thread is waiting on "genput" but the page in question is neither
BUSY nor WANTED.

No objections from tech-k...@.


To generate a diff of this commit:
cvs rdiff -u -r1.43 -r1.44 src/sys/miscfs/genfs/genfs_io.c
cvs rdiff -u -r1.70 -r1.71 src/sys/uvm/uvm_bio.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/miscfs/genfs/genfs_io.c
diff -u src/sys/miscfs/genfs/genfs_io.c:1.43 src/sys/miscfs/genfs/genfs_io.c:1.44
--- src/sys/miscfs/genfs/genfs_io.c:1.43	Fri Nov 19 05:38:10 2010
+++ src/sys/miscfs/genfs/genfs_io.c	Tue Nov 30 10:55:25 2010
@@ -1,4 +1,4 @@
-/*	$NetBSD: genfs_io.c,v 1.43 2010/11/19 05:38:10 uebayasi Exp $	*/
+/*	$NetBSD: genfs_io.c,v 1.44 2010/11/30 10:55:25 hannken Exp $	*/
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1993
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: genfs_io.c,v 1.43 2010/11/19 05:38:10 uebayasi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: genfs_io.c,v 1.44 2010/11/30 10:55:25 hannken Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -569,6 +569,7 @@
 			    iobytes);
 			skipbytes += iobytes;
 
+			mutex_enter(&uobj->vmobjlock);
 			for (i = 0; i < holepages; i++) {
 				if (memwrite) {
 					pgs[pidx + i]->flags &= ~PG_CLEAN;
@@ -577,6 +578,7 @@
 					pgs[pidx + i]->flags |= PG_RDONLY;
 				}
 			}
+			mutex_exit(&uobj->vmobjlock);
 			continue;
 		}
 
@@ -638,6 +640,7 @@
 		UVMHIST_LOG(ubchist, "gop_alloc off 0x%x/0x%x -> %d",
 		    startoffset, npages << PAGE_SHIFT, error,0);
 		if (!error) {
+			mutex_enter(&uobj->vmobjlock);
 			for (i = 0; i < npages; i++) {
 				struct vm_page *pg = pgs[i];
 
@@ -648,6 +651,7 @@
 				UVMHIST_LOG(ubchist, "mark dirty pg %p",
 				    pg,0,0,0);
 			}
+			mutex_exit(&uobj->vmobjlock);
 		}
 	}
 	if (!glocked) {

Index: src/sys/uvm/uvm_bio.c
diff -u src/sys/uvm/uvm_bio.c:1.70 src/sys/uvm/uvm_bio.c:1.71
--- src/sys/uvm/uvm_bio.c:1.70	Tue Jun 22 18:34:50 2010
+++ src/sys/uvm/uvm_bio.c	Tue Nov 30 10:55:25 2010
@@ -1,4 +1,4 @@
-/*	$NetBSD: uvm_bio.c,v 1.70 2010/06/22 18:34:50 rmind Exp $	*/
+/*	$NetBSD: uvm_bio.c,v 1.71 2010/11/30 10:55:25 hannken Exp $	*/
 
 /*
  * Copyright (c) 1998 Chuck Silvers.
@@ -34,7 +34,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_bio.c,v 1.70 2010/06/22 18:34:50 rmind Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_bio.c,v 1.71 2010/11/30 10:55:25 hannken Exp $");
 
 #include "opt_uvmhist.h"
 #include "opt_ubc.h"
@@ -645,6 +645,7 @@
 			memset((char *)umapva + endoff, 0, zerolen);
 		}
 		umap->flags &= ~UMAP_PAGES_LOCKED;
+		mutex_enter(&uobj->vmobjlock);
 		mutex_enter(&uvm_pageqlock);
 		for (i = 0; i < npages; i++) {
 			rv = pmap_extract(pmap_kernel(),
@@ -658,7 +659,6 @@
 		mutex_exit(&uvm_pageqlock);
 		pmap_kremove(umapva, ubc_winsize);
 		pmap_update(pmap_kernel());
-		mutex_enter(&uobj->vmobjlock);
 		uvm_page_unbusy(pgs, npages);
 		mutex_exit(&uobj->vmobjlock);
 		unmapped = true;