On 2019-06-17 16:04, Arnd Bergmann wrote:
On Mon, Jun 17, 2019 at 3:49 PM Roman Penyaev <rpenyaev@xxxxxxx> wrote:
> augment_tree_propagate_from(va);
>
> - if (type == NE_FIT_TYPE)
> - insert_vmap_area_augment(lva, &va->rb_node,
> - &free_vmap_area_root, &free_vmap_area_list);
> - }
> -
> return 0;
> }
Hi Arnd,
Seems the proper fix is just setting lva to NULL. The only place
where lva is allocated and then used is when type == NE_FIT_TYPE,
so according to my shallow understanding of the code everything
should be fine.
I don't see how NULL could work here. insert_vmap_area_augment()
passes the va pointer into find_va_links() and link_va(), both of
which dereference the pointer, see
Exactly, but insert_vmap_area_augement() accepts 'va', not 'lva',
but in your variant 'va' is already freed (see type == FL_FIT_TYPE
branch, on top of that function). So that should be use-after-free.
--
Roman
