Re: [PATCH 5.15.y] mm, kfence: support kmem_dump_obj() for KFENCE objects

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Apr 19, 2022 at 01:45:32PM +0200, Marco Elver wrote:
> commit 2dfe63e61cc31ee59ce951672b0850b5229cd5b0 upstream.
> 
> 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/
> Link: https://lkml.kernel.org/r/20220406131558.3558585-1-elver@google.com
> Fixes: b89fb5ef0ce6 ("mm, kfence: insert KFENCE hooks for SLUB")
> Fixes: d3fb45f370d9 ("mm, kfence: insert KFENCE hooks for SLAB")
> Signed-off-by: Marco Elver <elver@google.com>
> Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> Reported-by: kernel test robot <oliver.sang@intel.com>
> Acked-by: Vlastimil Babka <vbabka@suse.cz>	[slab]
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> [elver@google.com: backport - substitute uses of struct slab with page]
> Signed-off-by: Marco Elver <elver@google.com>
> ---
>  include/linux/kfence.h | 24 +++++++++++++++++++++
>  mm/kfence/core.c       | 21 -------------------
>  mm/kfence/kfence.h     | 21 +++++++++++++++++++
>  mm/kfence/report.c     | 47 ++++++++++++++++++++++++++++++++++++++++++
>  mm/slab.c              |  2 +-
>  mm/slab.h              |  2 +-
>  mm/slab_common.c       |  9 ++++++++
>  mm/slob.c              |  2 +-
>  mm/slub.c              |  2 +-
>  9 files changed, 105 insertions(+), 25 deletions(-)

Now queued up, thanks.

greg k-h