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Subject: Re: slub freelist issue / BUG: unable to handle page fault for
 address: 000000003ffe0018
To:     Kees Cook <keescook@chromium.org>
Cc:     Vlastimil Babka <vbabka@suse.cz>,
        "Rafael J. Wysocki" <rafael@kernel.org>,
        Robert Moore <robert.moore@intel.com>,
        Erik Kaneda <erik.kaneda@intel.com>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Christoph Lameter <cl@linux.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Marco Elver <elver@google.com>,
        Waiman Long <longman@redhat.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        Len Brown <lenb@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>
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From:   Vegard Nossum <vegard.nossum@oracle.com>
Message-ID: <2055681b-35cf-1ca6-00d1-c47868bbf28d@oracle.com>
Date:   Fri, 5 Jun 2020 18:37:55 +0200
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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