Re: [uml-devel] current_thread_info() returns invalid pointer in early UML boot code

[Richard W. <ric...@gm...>]

On Sat, May 21, 2016 at 3:51 PM, Vegard Nossum <veg...@gm...> wrote:
> Hi people,
>
> I'm having some trouble with using current_thread_info() during UML
> early boot. Sometimes it works just fine, but often I get segfaults
> because current_thread_info() is returning an invalid pointer. It
> looks random: 0x202118, 0x1003e0003, 0xd33b90b3, 0x6db043, etc.

Where do you use it?
Can you rule out a bad compiler optimization?
(We had such an issue a few years ago)

> Does anybody understand fully what's going on here, why it returns
> those invalid (seemingly random) values? If the problem is that we're
> on a wrong stack, can we switch stacks earlier during boot or
> something to make current_thread_info() always return a valid
> thread_info pointer?

Can't say much without more details.

-- 
Thanks,
//richard