This is a note to let you know that I've just added the patch titled
mm: fail get_vaddr_frames() for filesystem-dax mappings
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-fail-get_vaddr_frames-for-filesystem-dax-mappings.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From foo@baz Mon Feb 26 20:55:53 CET 2018
From: Dan Williams <dan.j.williams@xxxxxxxxx>
Date: Fri, 23 Feb 2018 14:06:16 -0800
Subject: mm: fail get_vaddr_frames() for filesystem-dax mappings
To: gregkh@xxxxxxxxxxxxxxxxxxx
Cc: Jan Kara <jack@xxxxxxx>, Joonyoung Shim <jy0922.shim@xxxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx, Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx>, Jeff Moyer <jmoyer@xxxxxxxxxx>, stable@xxxxxxxxxxxxxxx, Christoph Hellwig <hch@xxxxxx>, Inki Dae <inki.dae@xxxxxxxxxxx>, Doug Ledford <dledford@xxxxxxxxxx>, Jason Gunthorpe <jgg@xxxxxxxxxxxx>, Mel Gorman <mgorman@xxxxxxx>, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>, Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>, Kyungmin Park <kyungmin.park@xxxxxxxxxxx>, Sean Hefty <sean.hefty@xxxxxxxxx>, Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>, Hal Rosenstock <hal.rosenstock@xxxxxxxxx>, Vlastimil Babka <vbabka@xxxxxxx>
Message-ID: <151942357601.21775.3085470269801679738.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
From: Dan Williams <dan.j.williams@xxxxxxxxx>
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@xxxxxxxxx: add comment for vma_is_fsdax() check in get_vaddr_frames(), per Jan]
Link: http://lkml.kernel.org/r/151197874035.26211.4061781453123083667.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/151068939985.7446.15684639617389154187.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 3565fce3a659 ("mm, x86: get_user_pages() for dax mappings")
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
Reviewed-by: Jan Kara <jack@xxxxxxx>
Cc: Inki Dae <inki.dae@xxxxxxxxxxx>
Cc: Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx>
Cc: Joonyoung Shim <jy0922.shim@xxxxxxxxxxx>
Cc: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
Cc: Mauro Carvalho Chehab <mchehab@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Doug Ledford <dledford@xxxxxxxxxx>
Cc: Hal Rosenstock <hal.rosenstock@xxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Cc: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: Ross Zwisler <ross.zwisler@xxxxxxxxxxxxxxx>
Cc: Sean Hefty <sean.hefty@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
mm/frame_vector.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -52,6 +52,18 @@ int get_vaddr_frames(unsigned long start
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;
Patches currently in stable-queue which might be from dan.j.williams@xxxxxxxxx are
queue-4.9/mm-fix-devm_memremap_pages-collision-handling.patch
queue-4.9/ib-core-disable-memory-registration-of-filesystem-dax-vmas.patch
queue-4.9/mm-avoid-spurious-bad-pmd-warning-messages.patch
queue-4.9/mm-introduce-get_user_pages_longterm.patch
queue-4.9/mm-fail-get_vaddr_frames-for-filesystem-dax-mappings.patch
queue-4.9/fs-dax.c-fix-inefficiency-in-dax_writeback_mapping_range.patch
queue-4.9/device-dax-implement-split-to-catch-invalid-munmap-attempts.patch
queue-4.9/v4l2-disable-filesystem-dax-mapping-support.patch
queue-4.9/libnvdimm-dax-fix-1gb-aligned-namespaces-vs-physical-misalignment.patch
queue-4.9/x86-entry-64-clear-extra-registers-beyond-syscall-arguments-to-reduce-speculation-attack-surface.patch
queue-4.9/libnvdimm-fix-integer-overflow-static-analysis-warning.patch