Re: CVS commit: src/sys/kern

[christos%astron.com@localhost (Christos Zoulas)]

In article <6C2B4529-2F69-4B94-A580-A7B85057C605%me.com@localhost>,
Jason Thorpe  <thorpej%me.com@localhost> wrote:
>
>
>> On Dec 3, 2018, at 11:27 AM, Christos Zoulas <christos%astron.com@localhost> wrote:
>> 
>> I don't think that the things that KASLR randomizes by default are useful
>> to debugging. I.e. you can't depend on two successive kernel crashes to
>> have identical PTE addresses; OTOH you can depend that the text addresses
>> are the same (which are for GENERIC and are not for GENERIC_KASLR).
>
>Oh, that depends.  I would say if you are debugging a low-level VM
>problem, being able to have a predictable PTE address at the time of a
>crash could be VERY helpful.

I should have added "in general" :-) Yes, there are corner cases
(where you could depend on things being identical on the same
machine) in which not having ASLR can be useful. But I think that
if you are doing this level of debugging you probably know how to
turn it off... If that proves to be a common case we can add an
ifdef to facilitate turning it off...

christos