On Thu, May 28, 2020 at 12:25 AM Guenter Roeck <li...@roeck-us.net> wrote: > > On Wed, May 27, 2020 at 11:01:16AM +0200, Rafael J. Wysocki wrote: > > > > So Guenter, can you please test the patch below to see if it still > > introduces > > the problems seen by you on ARM? > > > > arm64 and arm64be boot tests pass with the patch below.
Great, thanks! > Some arm boot tests fail, but I think that is due to some other problem with > -next. > Hard to say for sure at this point because -next is pretty badly broken > overall. I'll need to run some bisects to see what is going on. I see. Thanks for giving this one a go. > > --- > > From: Heikki Krogerus <heikki.kroge...@linux.intel.com> > > Subject: [PATCH] kobject: Make sure the parent does not get released before > > its children > > > > In the function kobject_cleanup(), kobject_del(kobj) is > > called before the kobj->release(). That makes it possible to > > release the parent of the kobject before the kobject itself. > > > > To fix that, adding function __kboject_del() that does > > everything that kobject_del() does except release the parent > > reference. kobject_cleanup() then calls __kobject_del() > > instead of kobject_del(), and separately decrements the > > reference count of the parent kobject after kobj->release() > > has been called. > > > > Reported-by: Naresh Kamboju <naresh.kamb...@linaro.org> > > Reported-by: kernel test robot <rong.a.c...@intel.com> > > Fixes: 7589238a8cf3 ("Revert "software node: Simplify > > software_node_release() function"") > > Suggested-by: "Rafael J. Wysocki" <raf...@kernel.org> > > Signed-off-by: Heikki Krogerus <heikki.kroge...@linux.intel.com> > > [ rjw: Drop parent reference only when called __kobject_del() ] > > Signed-off-by: "Rafael J. Wysocki" <rafael.j.wyso...@intel.com> > > --- > > lib/kobject.c | 34 +++++++++++++++++++++++----------- > > 1 file changed, 23 insertions(+), 11 deletions(-) > > > > Index: linux-pm/lib/kobject.c > > =================================================================== > > --- linux-pm.orig/lib/kobject.c > > +++ linux-pm/lib/kobject.c > > @@ -599,14 +599,7 @@ out: > > } > > EXPORT_SYMBOL_GPL(kobject_move); > > > > -/** > > - * 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) > > +static void __kobject_del(struct kobject *kobj) > > { > > struct kernfs_node *sd; > > const struct kobj_type *ktype; > > @@ -625,9 +618,23 @@ 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); > > > > /** > > @@ -663,7 +670,9 @@ 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); > > + bool state_in_sysfs = kobj->state_in_sysfs; > > const char *name = kobj->name; > > > > pr_debug("kobject: '%s' (%p): %s, parent %p\n", > > @@ -681,10 +690,10 @@ static void kobject_cleanup(struct kobje > > } > > > > /* remove from sysfs if the caller did not do it */ > > - if (kobj->state_in_sysfs) { > > + if (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) { > > @@ -698,6 +707,9 @@ static void kobject_cleanup(struct kobje > > pr_debug("kobject: '%s': free name\n", name); > > kfree_const(name); > > } > > + > > + if (state_in_sysfs) > > + kobject_put(parent); > > } > > > > #ifdef CONFIG_DEBUG_KOBJECT_RELEASE > > > > > >