This is a note to let you know that I've just added the patch titled
Revert "kobject: Make sure the parent does not get released before
to my driver-core git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git
in the driver-core-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From e6764aa0e5530066dd969eccea2a1a7d177859a8 Mon Sep 17 00:00:00 2001
From: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Date: Sat, 23 May 2020 17:11:11 +0200
Subject: Revert "kobject: Make sure the parent does not get released before
its children"
This reverts commit 4ef12f7198023c09ad6d25b652bd8748c965c7fa.
Guenter reports:
All my arm64be (arm64 big endian) boot tests crash with this
patch applied. Reverting it fixes the problem. Crash log and
bisect results (from pending-fixes branch) below.
And also:
arm64 images don't crash but report lots of "poison overwritten"
backtraces like the one below. On arm, I see "refcount_t:
underflow", also attached. I didn't bisect those, but given the
context I would suspect the same culprit.
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200513151840.36400-1-heikki.krogerus@xxxxxxxxxxxxxxx
Cc: Naresh Kamboju <naresh.kamboju@xxxxxxxxxx>
Cc: kernel test robot <rong.a.chen@xxxxxxxxx>
Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx>
Cc: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
Cc: Brendan Higgins <brendanhiggins@xxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
lib/kobject.c | 30 ++++++++++--------------------
1 file changed, 10 insertions(+), 20 deletions(-)
diff --git a/lib/kobject.c b/lib/kobject.c
index 2bd631460e18..83198cb37d8d 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -599,7 +599,14 @@ int kobject_move(struct kobject *kobj, struct kobject *new_parent)
}
EXPORT_SYMBOL_GPL(kobject_move);
-static void __kobject_del(struct kobject *kobj)
+/**
+ * kobject_del() - Unlink kobject from hierarchy.
+ * @kobj: object.
+ *
+ * This is the function that should be called to delete an object
+ * successfully added via kobject_add().
+ */
+void kobject_del(struct kobject *kobj)
{
struct kernfs_node *sd;
const struct kobj_type *ktype;
@@ -618,23 +625,9 @@ static void __kobject_del(struct kobject *kobj)
kobj->state_in_sysfs = 0;
kobj_kset_leave(kobj);
+ kobject_put(kobj->parent);
kobj->parent = NULL;
}
-
-/**
- * kobject_del() - Unlink kobject from hierarchy.
- * @kobj: object.
- *
- * This is the function that should be called to delete an object
- * successfully added via kobject_add().
- */
-void kobject_del(struct kobject *kobj)
-{
- struct kobject *parent = kobj->parent;
-
- __kobject_del(kobj);
- kobject_put(parent);
-}
EXPORT_SYMBOL(kobject_del);
/**
@@ -670,7 +663,6 @@ EXPORT_SYMBOL(kobject_get_unless_zero);
*/
static void kobject_cleanup(struct kobject *kobj)
{
- struct kobject *parent = kobj->parent;
struct kobj_type *t = get_ktype(kobj);
const char *name = kobj->name;
@@ -692,7 +684,7 @@ static void kobject_cleanup(struct kobject *kobj)
if (kobj->state_in_sysfs) {
pr_debug("kobject: '%s' (%p): auto cleanup kobject_del\n",
kobject_name(kobj), kobj);
- __kobject_del(kobj);
+ kobject_del(kobj);
}
if (t && t->release) {
@@ -706,8 +698,6 @@ static void kobject_cleanup(struct kobject *kobj)
pr_debug("kobject: '%s': free name\n", name);
kfree_const(name);
}
-
- kobject_put(parent);
}
#ifdef CONFIG_DEBUG_KOBJECT_RELEASE
--
2.26.2
