mm, kfence: support kmem_dump_obj() for KFENCE objects

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/[email protected]
Fixes: b89fb5ef0ce6 ("mm, kfence: insert KFENCE hooks for SLUB")
Fixes: d3fb45f370d9 ("mm, kfence: insert KFENCE hooks for SLAB")
Signed-off-by: Marco Elver <[email protected]>
Reviewed-by: Hyeonggon Yoo <[email protected]>
Reported-by: kernel test robot <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>	[slab]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions