From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1E024C43387 for ; Thu, 10 Jan 2019 05:52:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E18E6206B7 for ; Thu, 10 Jan 2019 05:52:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727221AbfAJFwf convert rfc822-to-8bit (ORCPT ); Thu, 10 Jan 2019 00:52:35 -0500 Received: from mx1.redhat.com ([209.132.183.28]:54474 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725536AbfAJFwe (ORCPT ); Thu, 10 Jan 2019 00:52:34 -0500 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 10343C049DFC; Thu, 10 Jan 2019 05:52:34 +0000 (UTC) Received: from colo-mx.corp.redhat.com (colo-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DA031179CB; Thu, 10 Jan 2019 05:52:33 +0000 (UTC) Received: from zmail21.collab.prod.int.phx2.redhat.com (zmail21.collab.prod.int.phx2.redhat.com [10.5.83.24]) by colo-mx.corp.redhat.com (Postfix) with ESMTP id 371CA3F7CB; Thu, 10 Jan 2019 05:52:33 +0000 (UTC) Date: Thu, 10 Jan 2019 00:52:32 -0500 (EST) From: Pankaj Gupta To: Sean Christopherson Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, leozinho29 eu , Mike Galbraith , Adam Borowski , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Christian =?utf-8?Q?K=C3=B6nig?= , Jan Kara , Matthew Wilcox , Ross Zwisler , Dan Williams , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Michal Hocko , Felix Kuehling , Ralph Campbell , John Hubbard , Andrew Morton , Linus Torvalds Message-ID: <1861725446.61345592.1547099552878.JavaMail.zimbra@redhat.com> In-Reply-To: <20190110005117.18282-1-sean.j.christopherson@intel.com> References: <20190110005117.18282-1-sean.j.christopherson@intel.com> Subject: Re: [PATCH] mm/mmu_notifier: mm/rmap.c: Fix a mmu_notifier range bug in try_to_unmap_one MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT X-Originating-IP: [10.65.161.12, 10.4.195.7] Thread-Topic: mm/mmu_notifier: mm/rmap.c: Fix a mmu_notifier range bug in try_to_unmap_one Thread-Index: NxVIbboUSCe9zovHI7aboNWzdLjs1g== X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 10 Jan 2019 05:52:34 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > The conversion to use a structure for mmu_notifier_invalidate_range_*() > unintentionally changed the usage in try_to_unmap_one() to init the > 'struct mmu_notifier_range' with vma->vm_start instead of @address, > i.e. it invalidates the wrong address range. Revert to the correct > address range. > > Manifests as KVM use-after-free WARNINGs and subsequent "BUG: Bad page > state in process X" errors when reclaiming from a KVM guest due to KVM > removing the wrong pages from its own mappings. > > Reported-by: leozinho29_eu@hotmail.com > Reported-by: Mike Galbraith > Reported-by: Adam Borowski > Cc: Jérôme Glisse > Cc: Christian König > Cc: Jan Kara > Cc: Matthew Wilcox > Cc: Ross Zwisler > Cc: Dan Williams > Cc: Paolo Bonzini > Cc: Radim Krčmář > Cc: Michal Hocko > Cc: Felix Kuehling > Cc: Ralph Campbell > Cc: John Hubbard > Cc: Andrew Morton > Cc: Linus Torvalds > Fixes: ac46d4f3c432 ("mm/mmu_notifier: use structure for > invalidate_range_start/end calls v2") > Signed-off-by: Sean Christopherson > --- > > FWIW, I looked through all other calls to mmu_notifier_range_init() in > the patch and didn't spot any other unintentional functional changes. > > mm/rmap.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/rmap.c b/mm/rmap.c > index 68a1a5b869a5..0454ecc29537 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -1371,8 +1371,8 @@ static bool try_to_unmap_one(struct page *page, struct > vm_area_struct *vma, > * Note that the page can not be free in this function as call of > * try_to_unmap() must hold a reference on the page. > */ > - mmu_notifier_range_init(&range, vma->vm_mm, vma->vm_start, > - min(vma->vm_end, vma->vm_start + > + mmu_notifier_range_init(&range, vma->vm_mm, address, > + min(vma->vm_end, address + > (PAGE_SIZE << compound_order(page)))); > if (PageHuge(page)) { > /* > -- I was suspecting this patch for some other issue. But could not spot this after in depth analyzing the changed "invalidate_range_start/end calls". Its indeed a good catch. Reviewed-by: Pankaj gupta > 2.19.2 > >