On 5/28/20 3:57 AM, Rafael J. Wysocki wrote: > 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. >
The failing arm boot tests are due to various dts changes (commit "arm64: dts: vexpress: Move fixed devices out of bus node" and associated), unrelated to this patch. Guenter > 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 >>> >>> >>>