[lldb-dev] ASLR disabled by default - thoughts?

[Zachary Turner]

FWIW, once I get debugging working on Windows, I'm going to disable this
setting entirely as it doesn't make sense on Windows.  Is ASLR per-launch /
per-process on other platforms?   At least on Windows it's per-boot, so if
ASLR is enabled for a particular process, everything will be the same until
you reboot.


On Fri, Aug 15, 2014 at 6:52 AM, Todd Fiala <tfiala at google.com> wrote:

> Thanks all.
>
> I'm going to start looking into this today.
>
>
> On Fri, Aug 15, 2014 at 1:00 AM, Colin Riley <colin at codeplay.com> wrote:
>
>>  I'd agree with the default behavior being off and the command being
>> changed to an enable style. All targets we have worked with certainly
>> default to off, or don't have the feature at all.
>>
>> Colin
>>
>>
>>
>> On 15/08/2014 01:45, Eric Christopher wrote:
>>
>> I believe that disabling by default would match the gdb behavior yes? If
>> nothing else, yes, I'm a fan of this :)
>>
>> -eric
>> On Thu Aug 14 2014 at 5:30:52 PM Todd Fiala <tfiala at google.com> wrote:
>>
>>> Hey all,
>>>
>>>  Regarding this bug:
>>> http://llvm.org/bugs/show_bug.cgi?id=20658
>>>
>>>  We've been discussing the idea of having ASLR disabled by default when
>>> launching processes within lldb.  Currently it looks like the default
>>> behavior is to have it enabled, and require explicitly disabling to get
>>> that behavior for the process.
>>>
>>>  It seems like it might make more sense to have it disabled by default
>>> - that way code references would likely be static across debugger runs,
>>> which seems to be more what we want when tracking down issues across code
>>> runs.
>>>
>>>  Any thoughts on this?
>>>
>>>  The counterargument I could make for changing it would be (aside from
>>> legacy compatibility issues perhaps on the MacOSX/iOS side) - taking the
>>> exe out of its native state on the OS.  If a bug is ASLR sensitive, the
>>> user might miss it.  And so behavior in the debugger could differ from the
>>> exe in its native state.  Not sure how relevant that is for the majority of
>>> usages, though.
>>>
>>>  I'll be fixing the fact that Linux is ignoring this altogether.  But
>>> while I'm in there, I could flip the default if we wanted to do it.  If not
>>> globally, we'd probably pursue defaulting it on Linux (and Ed seems to like
>>> it for FreeBSD as well, so maybe for not Apple in that case?)
>>>  --
>>>    Todd Fiala |  Software Engineer |  tfiala at google.com |  650-943-3180
>>>   _______________________________________________
>>> lldb-dev mailing list
>>> lldb-dev at cs.uiuc.edu
>>> http://lists.cs.uiuc.edu/mailman/listinfo/lldb-dev
>>>
>>
>>
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>>
>> --
>> - Colin Riley
>> Games Technology Director
>>
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>
>
> --
> Todd Fiala | Software Engineer |  tfiala at google.com |  650-943-3180
>
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