Re: New vsyscall emulation breaks JITs

From: Andrew Lutomirski
Date: Tue Aug 09 2011 - 09:27:18 EST


On Fri, Aug 5, 2011 at 5:21 PM, Andi Kleen <andi@xxxxxxxxxxxxxx> wrote:
> On Fri, Aug 05, 2011 at 05:00:44PM -0400, Andrew Lutomirski wrote:
>> > If anything runtime, but really for me it looks like the vsyscall
>> > changes should be only in one of those limited compability paranoia
>> > patchkits.
>>
>> Switching it in runtime would be a giant mess because user code might
>
> You can always switch at boot time.
>
> But really serious binary incompatibility like this should not be default
> (not even talking about the slow down for existing binaries using time())

Why do we care about pin again?

$ ./pin -t obj-intel64/opcodemix.so -- /bin/ls
E:3.0 is not a supported linux release

So we've already broken it completely, and they'll have to release a
new version anyway to fix it. This version is from June of this year.

I'll send out the updated patch anyway for the benefit of DynamoRIO
(which is the only thing I know of that is affected).

--Andy
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/