Re: [PATCH v4 0/3] x86: modify_ldt improvement, test, and config option

From: Andy Lutomirski
Date: Tue Jul 28 2015 - 13:07:26 EST


On Tue, Jul 28, 2015 at 9:30 AM, Andrew Cooper
<andrew.cooper3@xxxxxxxxxx> wrote:
> I suspect that the set_ldt(NULL, 0) call hasn't reached Xen before
> xen_free_ldt() is attempting to nab back the pages which Xen still has
> mapped as an LDT.
>

I just instrumented it with yet more LSL instructions. I'm pretty
sure that set_ldt really is clearing at least LDT entry zero.
Nonetheless the free_ldt call still oopses.

--Andy

> ~Andrew



--
Andy Lutomirski
AMA Capital Management, LLC
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