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

Vegard Nossum
2020-06-05T16:38:46Z

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