Re: [PATCH 00/11] kobject: Require explicit initialization of struct kobj_type::release

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Tue, Oct 13, 2026 at 03:39:35PM -0700, Ian Rogers wrote:
> Clang supports the 'require_explicit_initialization' attribute on struct
> fields to enforce that the field is explicitly initialized when an
> aggregate object is constructed, emitting -Wuninitialized-explicit-init
> (enabled by default) if the field is omitted.
> 
> Following discussion at the Linux Plumbers Conference [1], this series
> introduces __require_explicit_initialization in
> include/linux/compiler_attributes.h and applies it to
> struct kobj_type::release.

Cool, sorry I missed that talk.

> As Documentation/core-api/kobject.rst notes:
>   "One important point cannot be overstated: every kobject must have a
>   release() method, and the kobject must persist (in a consistent state)
>   until that method is called. If these constraints are not met, the code
>   is flawed."
> 
> Annotating struct kobj_type::release caught 30 struct kobj_type
> definitions across the tree that omitted .release:
> - Patches 2-10 fix 10 struct kobj_type definitions where dynamically
>   allocated kobjects, ksets, or enclosing structures were either leaked on
>   kobject_put() or freed prematurely before kobject release (risking a
>   use-after-free when CONFIG_DEBUG_KOBJECT_RELEASE=y).
> - Patch 11 annotates struct kobj_type::release with
>   __require_explicit_initialization and explicitly sets .release = NULL
>   (with explanatory comments) on the remaining legacy struct kobj_type
>   definitions whose kobjects are static, per-CPU, or embedded in devm- or
>   parent-managed structures.

Sounds great, but let's fix up the users before adding the attribute.
Looks like some of these need another version so it might take a bit of
time to get them all merged.

thanks,

greg k-h

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