Re: slub freelist issue / BUG: unable to handle page fault for address: 000000003ffe0018

[Vegard Nossum]

On 2020-06-05 17:44, Kees Cook wrote:
> On Fri, Jun 05, 2020 at 04:44:51PM +0200, Vegard Nossum wrote:
> > That's it :-) This fixes it for me:
> >
> > diff --git a/drivers/acpi/acpica/nsaccess.c b/drivers/acpi/acpica/nsaccess.c
> > index 2566e2d4c7803..b76bbab917941 100644
> > --- a/drivers/acpi/acpica/nsaccess.c
> > +++ b/drivers/acpi/acpica/nsaccess.c
> > @@ -98,14 +98,12 @@ acpi_status acpi_ns_root_initialize(void)
> >                   * predefined names are at the root level. It is much easier
> > to
> >                   * just create and link the new node(s) here.
> >                   */
> > -               new_node =
> > -                   ACPI_ALLOCATE_ZEROED(sizeof(struct
> > acpi_namespace_node));
> > +               new_node = acpi_ns_create_node(*ACPI_CAST_PTR (u32,
> > init_val->name));
> >                  if (!new_node) {
> >                          status = AE_NO_MEMORY;
> >                          goto unlock_and_exit;
> >                  }
> >
> > -               ACPI_COPY_NAMESEG(new_node->name.ascii, init_val->name);
> >                  new_node->descriptor_type = ACPI_DESC_TYPE_NAMED;
> >                  new_node->type = init_val->type;
>
> I'm a bit confused by the internals of acpi_ns_create_note(). It can still
> end up calling ACPI_ALLOCATE_ZEROED() via acpi_os_acquire_object(). Is
> this fix correct?

include/acpi/platform/aclinuxex.h:static inline void 
*acpi_os_acquire_object(acpi_cache_t * cache)
include/acpi/platform/aclinuxex.h-{
include/acpi/platform/aclinuxex.h-      return kmem_cache_zalloc(cache,
include/acpi/platform/aclinuxex.h- 
irqs_disabled()? GFP_ATOMIC : GFP_KERNEL);
include/acpi/platform/aclinuxex.h-}

No comment.


Vegard