From 78b1cb3fe38a509dc0fdbdb52c742d4630db7502 Mon Sep 17 00:00:00 2001 From: Dan Williams Date: Fri, 23 Feb 2018 14:06:16 -0800 Subject: mm: fail get_vaddr_frames() for filesystem-dax mappings commit b7f0554a56f21fb3e636a627450a9add030889be upstream. Until there is a solution to the dma-to-dax vs truncate problem it is not safe to allow V4L2, Exynos, and other frame vector users to create long standing / irrevocable memory registrations against filesytem-dax vmas. [dan.j.williams@intel.com: add comment for vma_is_fsdax() check in get_vaddr_frames(), per Jan] Link: http://lkml.kernel.org/r/151197874035.26211.4061781453123083667.stgit@dwillia2-desk3.amr.corp.intel.com Link: http://lkml.kernel.org/r/151068939985.7446.15684639617389154187.stgit@dwillia2-desk3.amr.corp.intel.com Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings") Signed-off-by: Dan Williams Reviewed-by: Jan Kara Cc: Inki Dae Cc: Seung-Woo Kim Cc: Joonyoung Shim Cc: Kyungmin Park Cc: Mauro Carvalho Chehab Cc: Mel Gorman Cc: Vlastimil Babka Cc: Christoph Hellwig Cc: Doug Ledford Cc: Hal Rosenstock Cc: Jason Gunthorpe Cc: Jeff Moyer Cc: Ross Zwisler Cc: Sean Hefty Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/frame_vector.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/mm/frame_vector.c b/mm/frame_vector.c index db77dcb38afd..375a103d7a56 100644 --- a/mm/frame_vector.c +++ b/mm/frame_vector.c @@ -52,6 +52,18 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames, ret = -EFAULT; goto out; } + + /* + * While get_vaddr_frames() could be used for transient (kernel + * controlled lifetime) pinning of memory pages all current + * users establish long term (userspace controlled lifetime) + * page pinning. Treat get_vaddr_frames() like + * get_user_pages_longterm() and disallow it for filesystem-dax + * mappings. + */ + if (vma_is_fsdax(vma)) + return -EOPNOTSUPP; + if (!(vma->vm_flags & (VM_IO | VM_PFNMAP))) { vec->got_ref = true; vec->is_pfns = false; -- cgit v1.2.3