From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id 70C176B55AA for ; Fri, 31 Aug 2018 03:07:25 -0400 (EDT) Received: by mail-ed1-f69.google.com with SMTP id x24-v6so4458787edm.13 for ; Fri, 31 Aug 2018 00:07:25 -0700 (PDT) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id r9-v6si1501292edp.9.2018.08.31.00.07.23 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 31 Aug 2018 00:07:23 -0700 (PDT) Date: Fri, 31 Aug 2018 09:07:22 +0200 From: Joerg Roedel Subject: Re: 32-bit PTI with THP = userspace corruption Message-ID: <20180831070722.wnulbbmillxkw7ke@suse.de> References: <20180830205527.dmemjwxfbwvkdzk2@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: Meelis Roos Cc: Linux Kernel list , linux-mm@kvack.org, Thomas Gleixner 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