Re: [Xen-devel] CONFIG_SCRUB_DEBUG=y + arm64 + livepatch = Xen BUG at page_alloc.c:738

[Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>]

On 09/14/2017 05:26 PM, Konrad Rzeszutek Wilk wrote:
> On Wed, Sep 13, 2017 at 02:49:41PM -0400, Boris Ostrovsky wrote:
>> On 09/13/2017 02:25 PM, Julien Grall wrote:
>>> Hi,
>>>
>>> On 09/13/2017 07:05 PM, Boris Ostrovsky wrote:
>>>> On 09/13/2017 11:32 AM, Konrad Rzeszutek Wilk wrote:
>>>> Well, that's not a fix. This eliminates the case that something in
>>>> ARM-specific code (which I haven't tested) accidentally clears
>>>> _PGC_need_scrub.
>>>>
>>>> OK, I think I know what the problem is. You are using
>>>> CONFIG_SEPARATE_XENHEAP, are you?
>>> It seems the bug appear on Arm64, so CONFIG_SEPARATE_XENHEAP is not set.
>>>
>>> Note that Arm32 is using separate heap.
>>
>> For separate heap we will need
>>
>>
>> diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
>> index b5243fc..9f62ea2 100644
>> --- a/xen/common/page_alloc.c
>> +++ b/xen/common/page_alloc.c
>> @@ -2059,7 +2059,7 @@ void free_xenheap_pages(void *v, unsigned int order)
>>
>>      memguard_guard_range(v, 1 << (order + PAGE_SHIFT));
>>
>> -    free_heap_pages(virt_to_page(v), order, false);
>> +    free_heap_pages(virt_to_page(v), order, scrub_debug);
>>  }
>>
>>  #else
>>
>>
>> If that doesn't help then there are two cases where free_heap_pages is
>> called with 'false' --- one in alloc_domheap_pages() and the other in
>> online_page().
>>
>> Setting one and then the other would further narrow it down.
> It went further. See the serial log:

Hmm. As Julien said, this is ARM64 so this patch should not have any effect.

Have you tried flipping false to true in the two alloc_domheap_pages()
invocations that I mentioned?


-boris


>
> root@linaro-developer:~# xl info
> host                   : linaro-developer
> release                : 4.12.0-linaro-hikey960+
> version                : #3 SMP PREEMPT Mon Jul 17 13:26:13 EDT 2017
> machine                : aarch64
>


_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel