Re: [PATCH v2 0/4] x86: sigcontext fixes, again

From: Stas Sergeev
Date: Mon Oct 26 2015 - 07:46:08 EST


26.10.2015 04:25, Andy Lutomirski ÐÐÑÐÑ:
> This is take 2 at fixing x86 64-bit signals wrt SS. After a lot of
> thought, this is not controlled by any flags -- I would much prefer
> to avoid opt-in behavior. Instead, it just tries hard to avoid
> triggering the cases that break DOSEMU.
>
> Stas, this now seems to pass the test you sent me. It works with
> stock dosemu2 (I haven't tested classic dosemu because I can't get it
> to work regardless).
I'll test it myself then.
But this will have to wait till a week-end I am afraid.
In a mean time you can test vm86() - last time I tried,
I got oops and hard lockup.

> It also works with a patched dosemu2 that bypasses
> the userspace trampoline:
>
> https://github.com/amluto/dosemu2/commit/571b4d08dc885b7a133e444a2ad23e0d21366206
>
> With this applied, all of the x86 selftests pass on x86_64. That
> wasn't the case before -- ldt_gdt_64 was broken.
>
> This is a bit risky, and another option would be to do nothing at
> all. Then we'd disable the problematic self-tests (sigh), and
No, another option is a new SA_ flag.
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