On Wed, Sep 07, 2016 at 03:25:59PM +0300, Kirill A. Shutemov wrote: > Here's updated version. > > From 14d748bd8a7eb003efc10b1e5d5b8a644e7181b1 Mon Sep 17 00:00:00 2001 > From: "Kirill A. Shutemov" <[email protected]> > Date: Mon, 29 Aug 2016 15:32:50 +0300 > Subject: [PATCH] khugepaged: fix use-after-free in collapse_huge_page() > > hugepage_vma_revalidate() tries to re-check if we still should try to > collapse small pages into huge one after the re-acquiring mmap_sem. > > The problem Dmitry Vyukov reported[1] is that the vma found by > hugepage_vma_revalidate() can be suitable for huge pages, but not the > same vma we had before dropping mmap_sem. And dereferencing original vma > can lead to fun results.. > > Let's use vma hugepage_vma_revalidate() found instead of assuming it's > the same as what we had before the lock was dropped. > > [1] > http://lkml.kernel.org/r/cact4y+z3gigbvhca9krjfcjx0g70v_nrhbwkbu+ygoesbdk...@mail.gmail.com > > Signed-off-by: Kirill A. Shutemov <[email protected]> > Reported-by: Dmitry Vyukov <[email protected]> > --- > mm/khugepaged.c | 15 ++++++++------- > 1 file changed, 8 insertions(+), 7 deletions(-)
Reviewed-by: Andrea Arcangeli <[email protected]>
