On Fri, Oct 21, 2022 at 01:29:31AM -0400, Luben Tuikov wrote: > On 2022-10-20 22:20, Yang Yingliang wrote: > > The previous discussion link: > > https://lore.kernel.org/lkml/0db486eb-6927-927e-3629-958f8f211194@xxxxxxxxxx/T/ > > The very first discussion on this was here: > > https://www.spinics.net/lists/dri-devel/msg368077.html > > Please use this link, and not the that one up there you which quoted above, > and whose commit description is taken verbatim from the this link. > > > > > kset_register() is currently used in some places without calling > > kset_put() in error path, because the callers think it should be > > kset internal thing to do, but the driver core can not know what > > caller doing with that memory at times. The memory could be freed > > both in kset_put() and error path of caller, if it is called in > > kset_register(). > > As I explained in the link above, the reason there's > a memory leak is that one cannot call kset_register() without > the kset->kobj.name being set--kobj_add_internal() returns -EINVAL, > in this case, i.e. kset_register() fails with -EINVAL. > > Thus, the most common usage is something like this: > > kobj_set_name(&kset->kobj, format, ...); > kset->kobj.kset = parent_kset; > kset->kobj.ktype = ktype; > res = kset_register(kset); > > So, what is being leaked, is the memory allocated in kobj_set_name(), > by the common idiom shown above. This needs to be mentioned in > the documentation, at least, in case, in the future this is absolved > in kset_register() redesign, etc. Based on this, can kset_register() just clean up from itself when an error happens? Ideally that would be the case, as the odds of a kset being embedded in a larger structure is probably slim, but we would have to search the tree to make sure. thanks, greg k-h
