Messages in this thread | | | Date | Fri, 31 Aug 2018 09:07:22 +0200 | From | Joerg Roedel <> | Subject | Re: 32-bit PTI with THP = userspace corruption |
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On Fri, Aug 31, 2018 at 07:12:44AM +0300, Meelis Roos wrote: > > Thanks for the report! I'll try to reproduce the problem tomorrow and > > investigate it. Can you please check if any of the kernel configurations > > that show the bug has CONFIG_X86_PAE set? If not, can you please test > > if enabling this option still triggers the problem? > > Will check, but out of my memery there were 2 G3 HP Proliants that did > not fit into the pattern (problem did not appear). I have more than 4G > RAM in those and HIGHMEM_4G there, maybe that's it?
Yeah, I thought a bit about it, and for legacy paging the PMD paging level is the root-level where we do the mirroring between kernel and user page-table for PTI. This means we also need to collect A/D bits from both entries, which we don't do yet.
But that all means it shouldn't happen with CONFIG_X86_PAE=y.
I'll try to reproduce and work on a fix.
Thanks,
Joerg
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