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Dan Williams 7e3e888dfc libnvdimm/pfn: fix fsdax-mode namespace info-block zero-fields
At namespace creation time there is the potential for the "expected to
be zero" fields of a 'pfn' info-block to be filled with indeterminate
data.  While the kernel buffer is zeroed on allocation it is immediately
overwritten by nd_pfn_validate() filling it with the current contents of
the on-media info-block location.  For fields like, 'flags' and the
'padding' it potentially means that future implementations can not rely on
those fields being zero.

In preparation to stop using the 'start_pad' and 'end_trunc' fields for
section alignment, arrange for fields that are not explicitly
initialized to be guaranteed zero.  Bump the minor version to indicate
it is safe to assume the 'padding' and 'flags' are zero.  Otherwise,
this corruption is expected to benign since all other critical fields
are explicitly initialized.

Note The cc: stable is about spreading this new policy to as many
kernels as possible not fixing an issue in those kernels.  It is not
until the change titled "libnvdimm/pfn: Stop padding pmem namespaces to
section alignment" where this improper initialization becomes a problem.
So if someone decides to backport "libnvdimm/pfn: Stop padding pmem
namespaces to section alignment" (which is not tagged for stable), make
sure this pre-requisite is flagged.

Link: http://lkml.kernel.org/r/156092356065.979959.6681003754765958296.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 32ab0a3f51 ("libnvdimm, pmem: 'struct page' for pmem")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>	[ppc64]
Cc: <stable@vger.kernel.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18 17:08:07 -07:00
arch mm/sparsemem: convert kmalloc_section_memmap() to populate_section_memmap() 2019-07-18 17:08:07 -07:00
block docs conversion for v5.3-rc1 2019-07-16 12:21:41 -07:00
certs Revert "Merge tag 'keys-acl-20190703' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs" 2019-07-10 18:43:43 -07:00
crypto USB / PHY patches for 5.3-rc1 2019-07-11 15:40:06 -07:00
Documentation mm: document ZONE_DEVICE memory-model implications 2019-07-18 17:08:07 -07:00
drivers libnvdimm/pfn: fix fsdax-mode namespace info-block zero-fields 2019-07-18 17:08:07 -07:00
fs mm: thp: fix false negative of shmem vma's THP eligibility 2019-07-18 17:08:06 -07:00
include mm/sparsemem: support sub-section hotplug 2019-07-18 17:08:07 -07:00
init Merge branch 'akpm' (patches from Andrew) 2019-07-17 08:58:04 -07:00
ipc ipc/mqueue.c: only perform resource calculation if user valid 2019-07-16 19:23:24 -07:00
kernel mm/devm_memremap_pages: enable sub-section remap 2019-07-18 17:08:07 -07:00
lib Merge branch 'akpm' (patches from Andrew) 2019-07-17 08:58:04 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
mm mm/sparsemem: support sub-section hotplug 2019-07-18 17:08:07 -07:00
net pci-v5.3-changes 2019-07-15 20:44:49 -07:00
samples VFIO updates for v5.3-rc1 2019-07-17 11:23:13 -07:00
scripts Merge branch 'akpm' (patches from Andrew) 2019-07-17 08:58:04 -07:00
security docs conversion for v5.3-rc1 2019-07-16 12:21:41 -07:00
sound sound fixes for 5.3-rc1 2019-07-18 09:36:51 -07:00
tools Merge branch 'akpm' (patches from Andrew) 2019-07-17 08:58:04 -07:00
usr docs: early-userspace: move to driver-api guide 2019-07-15 11:03:01 -03:00
virt ARM: 2019-07-12 15:35:14 -07:00
.clang-format Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-04-17 11:26:25 -07:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: set git diff driver for C source code files 2016-10-07 18:46:30 -07:00
.gitignore .gitignore: exclude .get_maintainer.ignore and .gitattributes 2019-05-18 11:49:54 +09:00
.mailmap MAINTAINERS: Update my email address 2019-06-18 14:37:27 +01:00
COPYING COPYING: use the new text with points to the license files 2018-03-23 12:41:45 -06:00
CREDITS docs: admin-guide: move sysctl directory to it 2019-07-15 11:03:01 -03:00
Kbuild Kbuild updates for v5.1 2019-03-10 17:48:21 -07:00
Kconfig docs: kbuild: convert docs to ReST and rename to *.rst 2019-06-14 14:21:21 -06:00
MAINTAINERS More power management updates for 5.3-rc1 2019-07-18 09:32:28 -07:00
Makefile Kbuild updates for v5.3 2019-07-12 16:03:16 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.