[src/trunk]: src/sys/dev add KASSERT() just before setting sc_deferred, to en...

[jdolecek <jdolecek%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/847fc1db4ebf
branches:  trunk
changeset: 357945:847fc1db4ebf
user:      jdolecek <jdolecek%NetBSD.org@localhost>
date:      Mon Dec 04 22:15:52 2017 +0000

description:
add KASSERT() just before setting sc_deferred, to ensure this does
not trigger problem in PR kern/52769

diffstat:

 sys/dev/dksubr.c |  5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diffs (26 lines):

diff -r acaa52008541 -r 847fc1db4ebf sys/dev/dksubr.c
--- a/sys/dev/dksubr.c  Mon Dec 04 14:50:33 2017 +0000
+++ b/sys/dev/dksubr.c  Mon Dec 04 22:15:52 2017 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: dksubr.c,v 1.100 2017/10/29 09:44:17 mlelstv Exp $ */
+/* $NetBSD: dksubr.c,v 1.101 2017/12/04 22:15:52 jdolecek Exp $ */
 
 /*-
  * Copyright (c) 1996, 1997, 1998, 1999, 2002, 2008 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.100 2017/10/29 09:44:17 mlelstv Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dksubr.c,v 1.101 2017/12/04 22:15:52 jdolecek Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -422,6 +422,7 @@
                        error = dkd->d_diskstart(dksc->sc_dev, bp);
                        mutex_enter(&dksc->sc_iolock);
                        if (error == EAGAIN) {
+                               KASSERT(dksc->sc_deferred == NULL);
                                dksc->sc_deferred = bp;
                                disk_unbusy(&dksc->sc_dkdev, 0, (bp->b_flags & B_READ));
                                disk_wait(&dksc->sc_dkdev);