Re: [PATCH] mm: kfence: fix using kfence_metadata without initialization in show_object()

[Andrew Morton]

On Wed, 15 Mar 2023 09:07:40 +0100 Marco Elver <elver@xxxxxxxxxx> wrote:

> On Wed, 15 Mar 2023 at 04:45, Muchun Song <songmuchun@xxxxxxxxxxxxx> wrote:
> >
> > The variable kfence_metadata is initialized in kfence_init_pool(), then, it is
> > not initialized if kfence is disabled after booting. In this case, kfence_metadata
> > will be used (e.g. ->lock and ->state fields) without initialization when reading
> > /sys/kernel/debug/kfence/objects. There will be a warning if you enable
> > CONFIG_DEBUG_SPINLOCK. Fix it by creating debugfs files when necessary.
> >
> > Fixes: 0ce20dd84089 ("mm: add Kernel Electric-Fence infrastructure")
> > Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
> 
> Tested-by: Marco Elver <elver@xxxxxxxxxx>
> Reviewed-by: Marco Elver <elver@xxxxxxxxxx>

Thanks, I'll add cc:stable to this.

I assume the warning is the only known adverse effect of this bug?