Re: [Xen-devel] kasan_map_early_shadow() on Xen

[Andrey Ryabinin <a.ryabinin@samsung.com>]

On 03/03/2015 05:16 PM, Konrad Rzeszutek Wilk wrote:
> On Tue, Mar 03, 2015 at 04:15:06PM +0300, Andrey Ryabinin wrote:
>> On 03/03/2015 12:40 PM, Luis R. Rodriguez wrote:
>>> Andrey,
>>>
>>> I believe that on Xen we should disable kasan, would like confirmation
>>
>> I guess Xen guests won't work with kasan because Xen guests doesn't setup shadow
>> (kasan_map_early_shadow() is not called in xen guests).
>>
>> Disabling kasan for Xen in Kconfig is undesirable because that will disable kasan
>> for allmodconfig and allyesconfig builds, but I don't see other option for now.
> 
> Was there an bug reported for this? It would be good to CC the maintainers
> of Xen on that sort of thing.
> 

There was no report for this. I just looked at Xen code because of this Luis's mail
and I don't see how it could work with kasan.
Fixing this might be not trivial. We need to setup shadow memory before any kasan instrumented
function will run.
This is like with -fstack-protector (you need to setup gdt before calling any stack protected function).