From: Jerome Glisse <jglisse@redhat.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
leozinho29_eu@hotmail.com, "Mike Galbraith" <efault@gmx.de>,
"Adam Borowski" <kilobyte@angband.pl>,
"Christian König" <christian.koenig@amd.com>,
"Jan Kara" <jack@suse.cz>,
"Matthew Wilcox" <mawilcox@microsoft.com>,
"Ross Zwisler" <zwisler@kernel.org>,
"Dan Williams" <dan.j.williams@intel.com>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Radim Krčmář" <rkrcmar@redhat.com>,
"Michal Hocko" <mhocko@kernel.org>,
"Felix Kuehling" <felix.kuehling@amd.com>,
"Ralph Campbell" <rcampbell@nvidia.com>,
"John Hubbard" <jhubbard@nvidia.com>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Linus Torvalds" <torvalds@linux-foundation.org>
Subject: Re: [PATCH] mm/mmu_notifier: mm/rmap.c: Fix a mmu_notifier range bug in try_to_unmap_one
Date: Wed, 9 Jan 2019 20:42:02 -0500 [thread overview]
Message-ID: <20190110014200.GA4317@redhat.com> (raw)
In-Reply-To: <20190110005117.18282-1-sean.j.christopherson@intel.com>
On Wed, Jan 09, 2019 at 04:51:17PM -0800, Sean Christopherson wrote:
> 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 <efault@gmx.de>
> Reported-by: Adam Borowski <kilobyte@angband.pl>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
> Cc: Christian König <christian.koenig@amd.com>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Matthew Wilcox <mawilcox@microsoft.com>
> Cc: Ross Zwisler <zwisler@kernel.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Felix Kuehling <felix.kuehling@amd.com>
> Cc: Ralph Campbell <rcampbell@nvidia.com>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Fixes: ac46d4f3c432 ("mm/mmu_notifier: use structure for invalidate_range_start/end calls v2")
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>
> 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
>
next prev parent reply other threads:[~2019-01-10 1:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-10 0:51 [PATCH] mm/mmu_notifier: mm/rmap.c: Fix a mmu_notifier range bug in try_to_unmap_one Sean Christopherson
2019-01-10 1:42 ` Jerome Glisse [this message]
2019-01-10 5:52 ` Pankaj Gupta
2019-01-10 9:14 ` Adam Borowski
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