Re: [PATCH] mm, kfence: support kmem_dump_obj() for KFENCE objects

[Vlastimil Babka]

On 4/7/22 11:48, Marco Elver wrote:
> On Thu, 7 Apr 2022 at 11:43, Vlastimil Babka <vbabka@xxxxxxx> wrote:
>>
>> On 4/6/22 15:15, Marco Elver wrote:
>> > Calling kmem_obj_info() via kmem_dump_obj() on KFENCE objects has been
>> > producing garbage data due to the object not actually being maintained
>> > by SLAB or SLUB.
>> >
>> > Fix this by implementing __kfence_obj_info() that copies relevant
>> > information to struct kmem_obj_info when the object was allocated by
>> > KFENCE; this is called by a common kmem_obj_info(), which also calls the
>> > slab/slub/slob specific variant now called __kmem_obj_info().
>> >
>> > For completeness, kmem_dump_obj() now displays if the object was
>> > allocated by KFENCE.
>> >
>> > Link: https://lore.kernel.org/all/20220323090520.GG16885@xsang-OptiPlex-9020/
>> > Fixes: b89fb5ef0ce6 ("mm, kfence: insert KFENCE hooks for SLUB")
>> > Fixes: d3fb45f370d9 ("mm, kfence: insert KFENCE hooks for SLAB")
>> > Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
>> > Signed-off-by: Marco Elver <elver@xxxxxxxxxx>
>> > Reviewed-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
>>
>> Thanks.
>> Given the impact on slab, and my series exposing the bug, I will add this to
>> slab tree.
> 
> It's already in Andrew's tree:
> https://lore.kernel.org/all/20220406192351.2E115C385A5@xxxxxxxxxxxxxxx/T/#u

Ah, missed that.

> Does your series and this patch merge cleanly?

Yeah the dependency is not on the code level.

> If so, maybe leaving in
> -mm is fine. Of course I don't mind either way and it's up to you and
> Andrew.

Yeah should be fine as linux-next will be safe with both trees merged. Thanks.

> Thanks,
> -- Marco