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authorriastradh <riastradh@NetBSD.org>2023-05-22 14:59:34 +0000
committerriastradh <riastradh@NetBSD.org>2023-05-22 14:59:34 +0000
commit76031411ad161566edd0a91f01ee9860b5283cb2 (patch)
tree9950bbc7d91ba0a320b5427db7c19bd8a24a607d /sys/dev
parentf02816aceb52e8120f3a33d4328cea33f609dd84 (diff)
dk(4): Prevent race between dkwedge_get_parent_name and wedge detach.
Still races with parent detach but maybe this is better. XXX Maybe we should ditch dkwedge_get_parent_name -- it's used only by rf_containsboot, which kinda suggests it shouldn't exist.
Diffstat (limited to 'sys/dev')
-rw-r--r--sys/dev/dkwedge/dk.c21
1 files changed, 17 insertions, 4 deletions
diff --git a/sys/dev/dkwedge/dk.c b/sys/dev/dkwedge/dk.c
index 20d16630531..8920f51211f 100644
--- a/sys/dev/dkwedge/dk.c
+++ b/sys/dev/dkwedge/dk.c
@@ -1,4 +1,4 @@
-/* $NetBSD: dk.c,v 1.165 2023/05/22 14:59:25 riastradh Exp $ */
+/* $NetBSD: dk.c,v 1.166 2023/05/22 14:59:34 riastradh Exp $ */
/*-
* Copyright (c) 2004, 2005, 2006, 2007 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.165 2023/05/22 14:59:25 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dk.c,v 1.166 2023/05/22 14:59:34 riastradh Exp $");
#ifdef _KERNEL_OPT
#include "opt_dkwedge.h"
@@ -1210,6 +1210,16 @@ dkwedge_lookup(dev_t dev)
return device_lookup_private(&dk_cd, minor(dev));
}
+static struct dkwedge_softc *
+dkwedge_lookup_acquire(dev_t dev)
+{
+ device_t dv = device_lookup_acquire(&dk_cd, minor(dev));
+
+ if (dv == NULL)
+ return NULL;
+ return device_private(dv);
+}
+
static int
dk_open_parent(dev_t dev, int mode, struct vnode **vpp)
{
@@ -1925,8 +1935,11 @@ dkwedge_get_parent_name(dev_t dev)
if (major(dev) != bmaj && major(dev) != cmaj)
return NULL;
- struct dkwedge_softc *sc = dkwedge_lookup(dev);
+
+ struct dkwedge_softc *const sc = dkwedge_lookup_acquire(dev);
if (sc == NULL)
return NULL;
- return sc->sc_parent->dk_name;
+ const char *const name = sc->sc_parent->dk_name;
+ device_release(sc->sc_dev);
+ return name;
}