From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) by kanga.kvack.org (Postfix) with ESMTP id C5B848E0038 for ; Wed, 9 Jan 2019 19:51:24 -0500 (EST) Received: by mail-pg1-f197.google.com with SMTP id f125so5222066pgc.20 for ; Wed, 09 Jan 2019 16:51:24 -0800 (PST) Received: from mga05.intel.com (mga05.intel.com. [192.55.52.43]) by mx.google.com with ESMTPS id n3si18316322pld.36.2019.01.09.16.51.22 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 09 Jan 2019 16:51:23 -0800 (PST) From: Sean Christopherson Subject: [PATCH] mm/mmu_notifier: mm/rmap.c: Fix a mmu_notifier range bug in try_to_unmap_one Date: Wed, 9 Jan 2019 16:51:17 -0800 Message-Id: <20190110005117.18282-1-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, leozinho29_eu@hotmail.com, Mike Galbraith , Adam Borowski , =?UTF-8?q?J=C3=A9r=C3=B4me=20Glisse?= , =?UTF-8?q?Christian=20K=C3=B6nig?= , Jan Kara , Matthew Wilcox , Ross Zwisler , Dan Williams , Paolo Bonzini , =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= , Michal Hocko , Felix Kuehling , Ralph Campbell , John Hubbard , Andrew Morton , Linus Torvalds 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)) { /* -- 2.19.2