<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/tools/testing/nvdimm/test, branch v5.3.2</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>memremap: provide an optional internal refcount in struct dev_pagemap</title>
<updated>2019-07-02T17:32:44+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2019-06-26T12:27:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=24917f6b1041a73993178920656e13364f847995'/>
<id>24917f6b1041a73993178920656e13364f847995</id>
<content type='text'>
Provide an internal refcounting logic if no -&gt;ref field is provided
in the pagemap passed into devm_memremap_pages so that callers don't
have to reinvent it poorly.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Reviewed-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Tested-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Provide an internal refcounting logic if no -&gt;ref field is provided
in the pagemap passed into devm_memremap_pages so that callers don't
have to reinvent it poorly.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Reviewed-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Tested-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>memremap: pass a struct dev_pagemap to -&gt;kill and -&gt;cleanup</title>
<updated>2019-07-02T17:32:44+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2019-06-26T12:27:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=d8668bb0451c3c45b59dbcde2654e0539aad1d2a'/>
<id>d8668bb0451c3c45b59dbcde2654e0539aad1d2a</id>
<content type='text'>
Passing the actual typed structure leads to more understandable code
vs just passing the ref member.

Reported-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
Reviewed-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Tested-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Passing the actual typed structure leads to more understandable code
vs just passing the ref member.

Reported-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
Reviewed-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Tested-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>memremap: move dev_pagemap callbacks into a separate structure</title>
<updated>2019-07-02T17:32:44+00:00</updated>
<author>
<name>Christoph Hellwig</name>
<email>hch@lst.de</email>
</author>
<published>2019-06-26T12:27:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1e240e8d4a7d92232b6214e02a0a4197a53afd6c'/>
<id>1e240e8d4a7d92232b6214e02a0a4197a53afd6c</id>
<content type='text'>
The dev_pagemap is a growing too many callbacks.  Move them into a
separate ops structure so that they are not duplicated for multiple
instances, and an attacker can't easily overwrite them.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
Reviewed-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Tested-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The dev_pagemap is a growing too many callbacks.  Move them into a
separate ops structure so that they are not duplicated for multiple
instances, and an attacker can't easily overwrite them.

Signed-off-by: Christoph Hellwig &lt;hch@lst.de&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Reviewed-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
Reviewed-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Tested-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>mm/devm_memremap_pages: fix final page put race</title>
<updated>2019-06-14T03:34:56+00:00</updated>
<author>
<name>Dan Williams</name>
<email>dan.j.williams@intel.com</email>
</author>
<published>2019-06-13T22:56:33+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=50f44ee7248ad2f7984ef081974a6ecd09724b3e'/>
<id>50f44ee7248ad2f7984ef081974a6ecd09724b3e</id>
<content type='text'>
Logan noticed that devm_memremap_pages_release() kills the percpu_ref
drops all the page references that were acquired at init and then
immediately proceeds to unplug, arch_remove_memory(), the backing pages
for the pagemap.  If for some reason device shutdown actually collides
with a busy / elevated-ref-count page then arch_remove_memory() should
be deferred until after that reference is dropped.

As it stands the "wait for last page ref drop" happens *after*
devm_memremap_pages_release() returns, which is obviously too late and
can lead to crashes.

Fix this situation by assigning the responsibility to wait for the
percpu_ref to go idle to devm_memremap_pages() with a new -&gt;cleanup()
callback.  Implement the new cleanup callback for all
devm_memremap_pages() users: pmem, devdax, hmm, and p2pdma.

Link: http://lkml.kernel.org/r/155727339156.292046.5432007428235387859.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 41e94a851304 ("add devm_memremap_pages")
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Reported-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Cc: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Cc: "Jérôme Glisse" &lt;jglisse@redhat.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Logan noticed that devm_memremap_pages_release() kills the percpu_ref
drops all the page references that were acquired at init and then
immediately proceeds to unplug, arch_remove_memory(), the backing pages
for the pagemap.  If for some reason device shutdown actually collides
with a busy / elevated-ref-count page then arch_remove_memory() should
be deferred until after that reference is dropped.

As it stands the "wait for last page ref drop" happens *after*
devm_memremap_pages_release() returns, which is obviously too late and
can lead to crashes.

Fix this situation by assigning the responsibility to wait for the
percpu_ref to go idle to devm_memremap_pages() with a new -&gt;cleanup()
callback.  Implement the new cleanup callback for all
devm_memremap_pages() users: pmem, devdax, hmm, and p2pdma.

Link: http://lkml.kernel.org/r/155727339156.292046.5432007428235387859.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 41e94a851304 ("add devm_memremap_pages")
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Reported-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Reviewed-by: Ira Weiny &lt;ira.weiny@intel.com&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Cc: Bjorn Helgaas &lt;bhelgaas@google.com&gt;
Cc: "Jérôme Glisse" &lt;jglisse@redhat.com&gt;
Cc: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
Cc: "Rafael J. Wysocki" &lt;rafael@kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 295</title>
<updated>2019-06-05T15:36:38+00:00</updated>
<author>
<name>Thomas Gleixner</name>
<email>tglx@linutronix.de</email>
</author>
<published>2019-05-29T14:18:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=5b497af42fab12cadc0e29bcb7052cf9963603f5'/>
<id>5b497af42fab12cadc0e29bcb7052cf9963603f5</id>
<content type='text'>
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of version 2 of the gnu general public license as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 64 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.894819585@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of version 2 of the gnu general public license as
  published by the free software foundation this program is
  distributed in the hope that it will be useful but without any
  warranty without even the implied warranty of merchantability or
  fitness for a particular purpose see the gnu general public license
  for more details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 64 file(s).

Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Reviewed-by: Alexios Zavras &lt;alexios.zavras@intel.com&gt;
Reviewed-by: Allison Randal &lt;allison@lohutok.net&gt;
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.894819585@linutronix.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tools/testing/nvdimm: add watermarks for dax_pmem* modules</title>
<updated>2019-04-22T22:56:28+00:00</updated>
<author>
<name>Vishal Verma</name>
<email>vishal.l.verma@intel.com</email>
</author>
<published>2019-03-19T01:06:29+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=92f6f2d7f5c844faebf5b47d4a8f15de519b48c2'/>
<id>92f6f2d7f5c844faebf5b47d4a8f15de519b48c2</id>
<content type='text'>
Add nfit_test 'watermarks' for the dax_pmem, dax_pmem_core, and
dax_pmem_compat modules. This causes the nfit_test module to fail
loading in case any of these modules are also not overridden with the
ldconfig wrapped modules. Without this, nfit_test would sometimes fail
creation of device-dax namespaces on the nfit_test_bus with an unhelpful
error log such as:

    dax_pmem dax5.0: could not reserve metadata
    dax_pmem: probe of dax5.0 failed with error -16

Which was caused due to the unwrapped version of
devm_request_mem_region() being called.

Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Signed-off-by: Vishal Verma &lt;vishal.l.verma@intel.com&gt;
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add nfit_test 'watermarks' for the dax_pmem, dax_pmem_core, and
dax_pmem_compat modules. This causes the nfit_test module to fail
loading in case any of these modules are also not overridden with the
ldconfig wrapped modules. Without this, nfit_test would sometimes fail
creation of device-dax namespaces on the nfit_test_bus with an unhelpful
error log such as:

    dax_pmem dax5.0: could not reserve metadata
    dax_pmem: probe of dax5.0 failed with error -16

Which was caused due to the unwrapped version of
devm_request_mem_region() being called.

Cc: Dan Williams &lt;dan.j.williams@intel.com&gt;
Signed-off-by: Vishal Verma &lt;vishal.l.verma@intel.com&gt;
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tools/testing/nvdimm: Retain security state after overwrite</title>
<updated>2019-04-08T16:39:32+00:00</updated>
<author>
<name>Dave Jiang</name>
<email>dave.jiang@intel.com</email>
</author>
<published>2019-03-11T19:47:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2170a0d53bee1a6c1a4ebd042f99d85aafc6c0ea'/>
<id>2170a0d53bee1a6c1a4ebd042f99d85aafc6c0ea</id>
<content type='text'>
Overwrite retains the security state after completion of operation.  Fix
nfit_test to reflect this so that the kernel can test the behavior it is
more likely to see in practice.

Fixes: 926f74802cb1 ("tools/testing/nvdimm: Add overwrite support for nfit_test")
Signed-off-by: Dave Jiang &lt;dave.jiang@intel.com&gt;
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Overwrite retains the security state after completion of operation.  Fix
nfit_test to reflect this so that the kernel can test the behavior it is
more likely to see in practice.

Fixes: 926f74802cb1 ("tools/testing/nvdimm: Add overwrite support for nfit_test")
Signed-off-by: Dave Jiang &lt;dave.jiang@intel.com&gt;
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>libnvdimm/security: provide fix for secure-erase to use zero-key</title>
<updated>2019-03-30T15:26:37+00:00</updated>
<author>
<name>Dave Jiang</name>
<email>dave.jiang@intel.com</email>
</author>
<published>2019-03-27T18:10:44+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=037c8489ade669e0f09ad40d5b91e5e1159a14b1'/>
<id>037c8489ade669e0f09ad40d5b91e5e1159a14b1</id>
<content type='text'>
Add a zero key in order to standardize hardware that want a key of 0's to
be passed. Some platforms defaults to a zero-key with security enabled
rather than allow the OS to enable the security. The zero key would allow
us to manage those platform as well. This also adds a fix to secure erase
so it can use the zero key to do crypto erase. Some other security commands
already use zero keys. This introduces a standard zero-key to allow
unification of semantics cross nvdimm security commands.

Signed-off-by: Dave Jiang &lt;dave.jiang@intel.com&gt;
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add a zero key in order to standardize hardware that want a key of 0's to
be passed. Some platforms defaults to a zero-key with security enabled
rather than allow the OS to enable the security. The zero key would allow
us to manage those platform as well. This also adds a fix to secure erase
so it can use the zero key to do crypto erase. Some other security commands
already use zero keys. This introduces a standard zero-key to allow
unification of semantics cross nvdimm security commands.

Signed-off-by: Dave Jiang &lt;dave.jiang@intel.com&gt;
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge branch 'akpm' (patches from Andrew)</title>
<updated>2018-12-29T00:55:46+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2018-12-29T00:55:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f346b0becb1bc62e45495f9cdbae3eef35d0b635'/>
<id>f346b0becb1bc62e45495f9cdbae3eef35d0b635</id>
<content type='text'>
Merge misc updates from Andrew Morton:

 - large KASAN update to use arm's "software tag-based mode"

 - a few misc things

 - sh updates

 - ocfs2 updates

 - just about all of MM

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (167 commits)
  kernel/fork.c: mark 'stack_vm_area' with __maybe_unused
  memcg, oom: notify on oom killer invocation from the charge path
  mm, swap: fix swapoff with KSM pages
  include/linux/gfp.h: fix typo
  mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm
  hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race
  hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization
  memory_hotplug: add missing newlines to debugging output
  mm: remove __hugepage_set_anon_rmap()
  include/linux/vmstat.h: remove unused page state adjustment macro
  mm/page_alloc.c: allow error injection
  mm: migrate: drop unused argument of migrate_page_move_mapping()
  blkdev: avoid migration stalls for blkdev pages
  mm: migrate: provide buffer_migrate_page_norefs()
  mm: migrate: move migrate_page_lock_buffers()
  mm: migrate: lock buffers before migrate_page_move_mapping()
  mm: migration: factor out code to compute expected number of page references
  mm, page_alloc: enable pcpu_drain with zone capability
  kmemleak: add config to select auto scan
  mm/page_alloc.c: don't call kasan_free_pages() at deferred mem init
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Merge misc updates from Andrew Morton:

 - large KASAN update to use arm's "software tag-based mode"

 - a few misc things

 - sh updates

 - ocfs2 updates

 - just about all of MM

* emailed patches from Andrew Morton &lt;akpm@linux-foundation.org&gt;: (167 commits)
  kernel/fork.c: mark 'stack_vm_area' with __maybe_unused
  memcg, oom: notify on oom killer invocation from the charge path
  mm, swap: fix swapoff with KSM pages
  include/linux/gfp.h: fix typo
  mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm
  hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race
  hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization
  memory_hotplug: add missing newlines to debugging output
  mm: remove __hugepage_set_anon_rmap()
  include/linux/vmstat.h: remove unused page state adjustment macro
  mm/page_alloc.c: allow error injection
  mm: migrate: drop unused argument of migrate_page_move_mapping()
  blkdev: avoid migration stalls for blkdev pages
  mm: migrate: provide buffer_migrate_page_norefs()
  mm: migrate: move migrate_page_lock_buffers()
  mm: migrate: lock buffers before migrate_page_move_mapping()
  mm: migration: factor out code to compute expected number of page references
  mm, page_alloc: enable pcpu_drain with zone capability
  kmemleak: add config to select auto scan
  mm/page_alloc.c: don't call kasan_free_pages() at deferred mem init
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>mm, devm_memremap_pages: fix shutdown handling</title>
<updated>2018-12-28T20:11:47+00:00</updated>
<author>
<name>Dan Williams</name>
<email>dan.j.williams@intel.com</email>
</author>
<published>2018-12-28T08:34:57+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=a95c90f1e2c253b280385ecf3d4ebfe476926b28'/>
<id>a95c90f1e2c253b280385ecf3d4ebfe476926b28</id>
<content type='text'>
The last step before devm_memremap_pages() returns success is to allocate
a release action, devm_memremap_pages_release(), to tear the entire setup
down.  However, the result from devm_add_action() is not checked.

Checking the error from devm_add_action() is not enough.  The api
currently relies on the fact that the percpu_ref it is using is killed by
the time the devm_memremap_pages_release() is run.  Rather than continue
this awkward situation, offload the responsibility of killing the
percpu_ref to devm_memremap_pages_release() directly.  This allows
devm_memremap_pages() to do the right thing relative to init failures and
shutdown.

Without this change we could fail to register the teardown of
devm_memremap_pages().  The likelihood of hitting this failure is tiny as
small memory allocations almost always succeed.  However, the impact of
the failure is large given any future reconfiguration, or disable/enable,
of an nvdimm namespace will fail forever as subsequent calls to
devm_memremap_pages() will fail to setup the pgmap_radix since there will
be stale entries for the physical address range.

An argument could be made to require that the -&gt;kill() operation be set in
the @pgmap arg rather than passed in separately.  However, it helps code
readability, tracking the lifetime of a given instance, to be able to grep
the kill routine directly at the devm_memremap_pages() call site.

Link: http://lkml.kernel.org/r/154275558526.76910.7535251937849268605.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...")
Reviewed-by: "Jérôme Glisse" &lt;jglisse@redhat.com&gt;
Reported-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Balbir Singh &lt;bsingharora@gmail.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The last step before devm_memremap_pages() returns success is to allocate
a release action, devm_memremap_pages_release(), to tear the entire setup
down.  However, the result from devm_add_action() is not checked.

Checking the error from devm_add_action() is not enough.  The api
currently relies on the fact that the percpu_ref it is using is killed by
the time the devm_memremap_pages_release() is run.  Rather than continue
this awkward situation, offload the responsibility of killing the
percpu_ref to devm_memremap_pages_release() directly.  This allows
devm_memremap_pages() to do the right thing relative to init failures and
shutdown.

Without this change we could fail to register the teardown of
devm_memremap_pages().  The likelihood of hitting this failure is tiny as
small memory allocations almost always succeed.  However, the impact of
the failure is large given any future reconfiguration, or disable/enable,
of an nvdimm namespace will fail forever as subsequent calls to
devm_memremap_pages() will fail to setup the pgmap_radix since there will
be stale entries for the physical address range.

An argument could be made to require that the -&gt;kill() operation be set in
the @pgmap arg rather than passed in separately.  However, it helps code
readability, tracking the lifetime of a given instance, to be able to grep
the kill routine directly at the devm_memremap_pages() call site.

Link: http://lkml.kernel.org/r/154275558526.76910.7535251937849268605.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams &lt;dan.j.williams@intel.com&gt;
Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...")
Reviewed-by: "Jérôme Glisse" &lt;jglisse@redhat.com&gt;
Reported-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Reviewed-by: Logan Gunthorpe &lt;logang@deltatee.com&gt;
Reviewed-by: Christoph Hellwig &lt;hch@lst.de&gt;
Cc: Balbir Singh &lt;bsingharora@gmail.com&gt;
Cc: Michal Hocko &lt;mhocko@suse.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
