Module Name: src
Committed By: riastradh
Date: Mon May 22 14:59:34 UTC 2023
Modified Files:
src/sys/dev/dkwedge: dk.c
Log Message:
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.
To generate a diff of this commit:
cvs rdiff -u -r1.165 -r1.166 src/sys/dev/dkwedge/dk.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/dev/dkwedge/dk.c
diff -u src/sys/dev/dkwedge/dk.c:1.165 src/sys/dev/dkwedge/dk.c:1.166
--- src/sys/dev/dkwedge/dk.c:1.165 Mon May 22 14:59:25 2023
+++ src/sys/dev/dkwedge/dk.c Mon May 22 14:59:34 2023
@@ -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;
}
