Messages in this thread | | | From | Dmitry Torokhov <> | Date | Mon, 25 May 2020 15:49:01 -0700 | Subject | Re: [PATCH 2/2] kobject: send KOBJ_REMOVE uevent when the object is removed from sysfs |
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On Sun, May 24, 2020 at 8:34 AM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > It is possible for a KOBJ_REMOVE uevent to be sent to userspace way > after the files are actually gone from sysfs, due to how reference > counting for kobjects work. This should not be a problem, but it would > be good to properly send the information when things are going away, not > at some later point in time in the future. > > Before this move, if a kobject's parent was torn down before the child,
^^^^ And this is the root of the problem and what has to be fixed.
> when the call to kobject_uevent() happened, the parent walk to try to > reconstruct the full path of the kobject could be a total mess and cause > crashes. It's not good to try to tear down a kobject tree from top > down, but let's at least try to not to crash if a user does so.
One can try, but if we keep proper reference counting then kobject core should take care of actually releasing objects in the right order. I do not think you should keep this patch, and instead see if we can push call to kobject_put(kobj->parent) into kobject_cleanup().
Thanks.
-- Dmitry
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