Re: [PATCH] kernel: enable page poisoning on x86_64

[Michael Tremer <michael.tremer@ipfire.org>]

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Hey,

> On 14 Apr 2020, at 15:36, Peter Müller <peter.mueller(a)ipfire.org> wrote:
> 
> Hello Michael,
> 
> possibly, but I consider this as being too important in order to drop it due
> to performance concerns. CONFIG_PAGE_POISONING_NO_SANITY reduces some performance
> overhead of page poisoning, but since this is currently not enabled on i586,
> I did not use in on x86_64, either.

Hmm, I am really not happy with such inconsistent configurations across multiple architectures.

This is either a feature that we want or not, but we do not want it on one platform and not on the other.

Although I would consider the performance overhead on x86_64 much smaller than i586. PAE might have the same advantage than x86_64.

> As mentioned, this is active on i586 already and I have not heard of IPFire
> being unusable on that architecture. :-)

Well, let’s say it is not running that well any more.

-Michael

> 
> Thanks, and best regards,
> Peter Müller
> 
>> Hi,
>> 
>> Can you perform any performance benchmarks to see how much this impacts IPsec and IPS throughput?
>> 
>> -Michael
>> 
>>> On 14 Apr 2020, at 15:32, Peter Müller <peter.mueller(a)ipfire.org> wrote:
>>> 
>>> This is already active on i586 and prevents information leaks from freed
>>> data.
>>> 
>>> Cc: Arne Fitzenreiter <arne.fitzenreiter(a)ipfire.org>
>>> Signed-off-by: Peter Müller <peter.mueller(a)ipfire.org>
>>> ---
>>> config/kernel/kernel.config.x86_64-ipfire | 4 +++-
>>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>> 
>>> diff --git a/config/kernel/kernel.config.x86_64-ipfire b/config/kernel/kernel.config.x86_64-ipfire
>>> index b16d13504..f6819859d 100644
>>> --- a/config/kernel/kernel.config.x86_64-ipfire
>>> +++ b/config/kernel/kernel.config.x86_64-ipfire
>>> @@ -6387,7 +6387,9 @@ CONFIG_DEBUG_KERNEL=y
>>> #
>>> # CONFIG_PAGE_EXTENSION is not set
>>> # CONFIG_DEBUG_PAGEALLOC is not set
>>> -# CONFIG_PAGE_POISONING is not set
>>> +CONFIG_PAGE_POISONING=y
>>> +# CONFIG_PAGE_POISONING_NO_SANITY is not set
>>> +CONFIG_PAGE_POISONING_ZERO=y
>>> # CONFIG_DEBUG_PAGE_REF is not set
>>> # CONFIG_DEBUG_RODATA_TEST is not set
>>> # CONFIG_DEBUG_OBJECTS is not set
>>> -- 
>>> 2.16.4
>>