The __kthread_queue_delayed_work is not exported so
make it static, to avoid the following sparse warning:

  kernel/kthread.c:869:6: warning: symbol '__kthread_queue_delayed_work' was not declared. Should it be static?
Signed-off-by: NBen Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull virtio fixes from Michael Tsirkin:
 "Some minor bugfixes"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  vhost/test: stop device before reset
  tools/virtio: xen stub
  tools/virtio: more stubs

Pull SCSI fixes from James Bottomley:
 "Five changes, two in drivers (qla2xxx, zfcp), one to MAINTAINERS
  (qla2xxx) and two in the core.

  The last two are mostly about removing incorrect messages from the
  kernel log: the resid message is definitely wrong and the sync cache
  on protected drive problem is arguably wrong"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: MAINTAINERS: Update qla2xxx driver
  scsi: zfcp: fix reaction on bit error threshold notification
  scsi: core: save/restore command resid for error handling
  scsi: qla2xxx: Remove WARN_ON_ONCE in qla2x00_status_cont_entry()
  scsi: sd: Ignore a failure to sync cache due to lack of authorization

HAVE_FAST_GUP enables the lockless quick page table walker for simple
cases, and is a nice optimization for some random loads that can then
use get_user_pages_fast() rather than the more careful page walker.

However, for some unexplained reason, it seems to be subtly broken on
sparc64.  The breakage is only with some compiler versions and some
hardware, and nobody seems to have figured out what triggers it,
although there's a simple reprodicer for the problem when it does
trigger.

The problem was introduced with the conversion to the generic GUP code
in commit 7b9afb86 ("sparc64: use the generic get_user_pages_fast
code"), but nothing looks obviously wrong in that conversion.  It may be
a compiler bug that just hits us with the code reorganization.  Or it
may be something very specific to sparc64.

This disables HAVE_FAST_GUP entirely.  That makes things like futexes a
bit slower, but at least they work.  If we can figure out the trigger,
that would be lovely, but it's been three months already..

Link: https://lore.kernel.org/lkml/20190717215956.GA30369@altlinux.org/
Fixes: 7b9afb86 ("sparc64: use the generic get_user_pages_fast code")
Reported-by: NDmitry V Levin <ldv@altlinux.org>
Reported-by: NAnatoly Pugachev <matorola@gmail.com>
Requested-by: NMeelis Roos <mroos@linux.ee>
Suggested-by: NChristoph Hellwig <hch@infradead.org>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull parisc fixes from Helge Deller:

 - Fix a parisc-specific fallout of Christoph's
   dma_set_mask_and_coherent() patches (Sven)

 - Fix a vmap memory leak in ioremap()/ioremap() (Helge)

 - Some minor cleanups and documentation updates (Nick, Helge)

* 'parisc-5.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Remove 32-bit DMA enforcement from sba_iommu
  parisc: Fix vmap memory leak in ioremap()/iounmap()
  parisc: prefer __section from compiler_attributes.h
  parisc: sysctl.c: Use CONFIG_PARISC instead of __hppa_ define
  MAINTAINERS: Add hp_sdc drivers to parisc arch

Pull dmi fix from Jean Delvare.

* 'dmi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jdelvare/staging:
  firmware: dmi: Fix unlikely out-of-bounds read in save_mem_devices

Merge more fixes from Andrew Morton:
 "The usual shower of hotfixes and some followups to the recently merged
  page_owner enhancements"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/memory-failure: poison read receives SIGKILL instead of SIGBUS if mmaped more than once
  mm/slab.c: fix kernel-doc warning for __ksize()
  xarray.h: fix kernel-doc warning
  bitmap.h: fix kernel-doc warning and typo
  fs/fs-writeback.c: fix kernel-doc warning
  fs/libfs.c: fix kernel-doc warning
  fs/direct-io.c: fix kernel-doc warning
  mm, compaction: fix wrong pfn handling in __reset_isolation_pfn()
  mm, hugetlb: allow hugepage allocations to reclaim as needed
  lib/test_meminit: add a kmem_cache_alloc_bulk() test
  mm/slub.c: init_on_free=1 should wipe freelist ptr for bulk allocations
  lib/generic-radix-tree.c: add kmemleak annotations
  mm/slub: fix a deadlock in show_slab_objects()
  mm, page_owner: rename flag indicating that page is allocated
  mm, page_owner: decouple freeing stack trace from debug_pagealloc
  mm, page_owner: fix off-by-one error in __set_page_owner_handle()

Mmap /dev/dax more than once, then read the poison location using
address from one of the mappings.  The other mappings due to not having
the page mapped in will cause SIGKILLs delivered to the process.
SIGKILL succeeds over SIGBUS, so user process loses the opportunity to
handle the UE.

Although one may add MAP_POPULATE to mmap(2) to work around the issue,
MAP_POPULATE makes mapping 128GB of pmem several magnitudes slower, so
isn't always an option.

Details -

  ndctl inject-error --block=10 --count=1 namespace6.0

  ./read_poison -x dax6.0 -o 5120 -m 2
  mmaped address 0x7f5bb6600000
  mmaped address 0x7f3cf3600000
  doing local read at address 0x7f3cf3601400
  Killed

Console messages in instrumented kernel -

  mce: Uncorrected hardware memory error in user-access at edbe201400
  Memory failure: tk->addr = 7f5bb6601000
  Memory failure: address edbe201: call dev_pagemap_mapping_shift
  dev_pagemap_mapping_shift: page edbe201: no PUD
  Memory failure: tk->size_shift == 0
  Memory failure: Unable to find user space address edbe201 in read_poison
  Memory failure: tk->addr = 7f3cf3601000
  Memory failure: address edbe201: call dev_pagemap_mapping_shift
  Memory failure: tk->size_shift = 21
  Memory failure: 0xedbe201: forcibly killing read_poison:22434 because of failure to unmap corrupted page
    => to deliver SIGKILL
  Memory failure: 0xedbe201: Killing read_poison:22434 due to hardware memory corruption
    => to deliver SIGBUS

Link: http://lkml.kernel.org/r/1565112345-28754-3-git-send-email-jane.chu@oracle.comSigned-off-by: NJane Chu <jane.chu@oracle.com>
Suggested-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reviewed-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix kernel-doc warning in mm/slab.c:

  mm/slab.c:4215: warning: Function parameter or member 'objp' not described in '__ksize'

Also add Return: documentation section for this function.

Link: http://lkml.kernel.org/r/68c9fd7d-f09e-d376-e292-c7b2bdf1774d@infradead.org
Fixes: 10d1f8cb ("mm/slab: refactor common ksize KASAN logic into slab_common.c")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Acked-by: NMarco Elver <elver@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix (Sphinx) kernel-doc warning in <linux/xarray.h>:

  include/linux/xarray.h:232: WARNING: Unexpected indentation.

Link: http://lkml.kernel.org/r/89ba2134-ce23-7c10-5ee1-ef83b35aa984@infradead.org
Fixes: a3e4d3f9 ("XArray: Redesign xa_alloc API")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix kernel-doc warning in <linux/bitmap.h>:

  include/linux/bitmap.h:341: warning: Function parameter or member 'nbits' not described in 'bitmap_or_equal'

Also fix small typo (bitnaps).

Link: http://lkml.kernel.org/r/0729ea7a-2c0d-b2c5-7dd3-3629ee0803e2@infradead.org
Fixes: b9fa6442 ("cpumask: Implement cpumask_or_equal()")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix kernel-doc warning in fs/fs-writeback.c:

  fs/fs-writeback.c:913: warning: Excess function parameter 'nr_pages' description in 'cgroup_writeback_by_id'

Link: http://lkml.kernel.org/r/756645ac-0ce8-d47e-d30a-04d9e4923a4f@infradead.org
Fixes: d62241c7 ("writeback, memcg: Implement cgroup_writeback_by_id()")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix kernel-doc warning in fs/libfs.c:

  fs/libfs.c:496: warning: Excess function parameter 'available' description in 'simple_write_end'

Link: http://lkml.kernel.org/r/5fc9d70b-e377-0ec9-066a-970d49579041@infradead.org
Fixes: ad2a722f ("libfs: Open code simple_commit_write into only user")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Boaz Harrosh <boazh@netapp.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix kernel-doc warning in fs/direct-io.c:

  fs/direct-io.c:258: warning: Excess function parameter 'offset' description in 'dio_complete'

Also, don't mark this function as having kernel-doc notation since it is
not exported.

Link: http://lkml.kernel.org/r/97908511-4328-4a56-17fe-f43a1d7aa470@infradead.org
Fixes: 6d544bb4 ("dio: centralize completion in dio_complete()")
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Cc: Zach Brown <zab@zabbo.net>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Florian and Dave reported [1] a NULL pointer dereference in
__reset_isolation_pfn().  While the exact cause is unclear, staring at
the code revealed two bugs, which might be related.

One bug is that if zone starts in the middle of pageblock, block_page
might correspond to different pfn than block_pfn, and then the
pfn_valid_within() checks will check different pfn's than those accessed
via struct page.  This might result in acessing an unitialized page in
CONFIG_HOLES_IN_ZONE configs.

The other bug is that end_page refers to the first page of next
pageblock and not last page of current pageblock.  The online and valid
check is then wrong and with sections, the while (page < end_page) loop
might wander off actual struct page arrays.

[1] https://lore.kernel.org/linux-xfs/87o8z1fvqu.fsf@mid.deneb.enyo.de/

Link: http://lkml.kernel.org/r/20191008152915.24704-1-vbabka@suse.cz
Fixes: 6b0868c8 ("mm/compaction.c: correct zone boundary handling when resetting pageblock skip hints")
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Reported-by: NFlorian Weimer <fw@deneb.enyo.de>
Reported-by: NDave Chinner <david@fromorbit.com>
Acked-by: NMel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit b39d0ee2 ("mm, page_alloc: avoid expensive reclaim when
compaction may not succeed") has chnaged the allocator to bail out from
the allocator early to prevent from a potentially excessive memory
reclaim.  __GFP_RETRY_MAYFAIL is designed to retry the allocation,
reclaim and compaction loop as long as there is a reasonable chance to
make forward progress.  Neither COMPACT_SKIPPED nor COMPACT_DEFERRED at
the INIT_COMPACT_PRIORITY compaction attempt gives this feedback.

The most obvious affected subsystem is hugetlbfs which allocates huge
pages based on an admin request (or via admin configured overcommit).  I
have done a simple test which tries to allocate half of the memory for
hugetlb pages while the memory is full of a clean page cache.  This is
not an unusual situation because we try to cache as much of the memory
as possible and sysctl/sysfs interface to allocate huge pages is there
for flexibility to allocate hugetlb pages at any time.

System has 1GB of RAM and we are requesting 515MB worth of hugetlb pages
after the memory is prefilled by a clean page cache:

  root@test1:~# cat hugetlb_test.sh

  set -x
  echo 0 > /proc/sys/vm/nr_hugepages
  echo 3 > /proc/sys/vm/drop_caches
  echo 1 > /proc/sys/vm/compact_memory
  dd if=/mnt/data/file-1G of=/dev/null bs=$((4<<10))
  TS=$(date +%s)
  echo 256 > /proc/sys/vm/nr_hugepages
  cat /proc/sys/vm/nr_hugepages

The results for 2 consecutive runs on clean 5.3

  root@test1:~# sh hugetlb_test.sh
  + echo 0
  + echo 3
  + echo 1
  + dd if=/mnt/data/file-1G of=/dev/null bs=4096
  262144+0 records in
  262144+0 records out
  1073741824 bytes (1.1 GB) copied, 21.0694 s, 51.0 MB/s
  + date +%s
  + TS=1569905284
  + echo 256
  + cat /proc/sys/vm/nr_hugepages
  256
  root@test1:~# sh hugetlb_test.sh
  + echo 0
  + echo 3
  + echo 1
  + dd if=/mnt/data/file-1G of=/dev/null bs=4096
  262144+0 records in
  262144+0 records out
  1073741824 bytes (1.1 GB) copied, 21.7548 s, 49.4 MB/s
  + date +%s
  + TS=1569905311
  + echo 256
  + cat /proc/sys/vm/nr_hugepages
  256

Now with b39d0ee2 applied

  root@test1:~# sh hugetlb_test.sh
  + echo 0
  + echo 3
  + echo 1
  + dd if=/mnt/data/file-1G of=/dev/null bs=4096
  262144+0 records in
  262144+0 records out
  1073741824 bytes (1.1 GB) copied, 20.1815 s, 53.2 MB/s
  + date +%s
  + TS=1569905516
  + echo 256
  + cat /proc/sys/vm/nr_hugepages
  11
  root@test1:~# sh hugetlb_test.sh
  + echo 0
  + echo 3
  + echo 1
  + dd if=/mnt/data/file-1G of=/dev/null bs=4096
  262144+0 records in
  262144+0 records out
  1073741824 bytes (1.1 GB) copied, 21.9485 s, 48.9 MB/s
  + date +%s
  + TS=1569905541
  + echo 256
  + cat /proc/sys/vm/nr_hugepages
  12

The success rate went down by factor of 20!

Although hugetlb allocation requests might fail and it is reasonable to
expect them to under extremely fragmented memory or when the memory is
under a heavy pressure but the above situation is not that case.

Fix the regression by reverting back to the previous behavior for
__GFP_RETRY_MAYFAIL requests and disable the beail out heuristic for
those requests.

Mike said:

: hugetlbfs allocations are commonly done via sysctl/sysfs shortly after
: boot where this may not be as much of an issue.  However, I am aware of at
: least three use cases where allocations are made after the system has been
: up and running for quite some time:
:
: - DB reconfiguration.  If sysctl/sysfs fails to get required number of
:   huge pages, system is rebooted to perform allocation after boot.
:
: - VM provisioning.  If unable get required number of huge pages, fall
:   back to base pages.
:
: - An application that does not preallocate pool, but rather allocates
:   pages at fault time for optimal NUMA locality.
:
: In all cases, I would expect b39d0ee2 to cause regressions and
: noticable behavior changes.
:
: My quick/limited testing in
: https://lkml.kernel.org/r/3468b605-a3a9-6978-9699-57c52a90bd7e@oracle.com
: was insufficient.  It was also mentioned that if something like
: b39d0ee2 went forward, I would like exemptions for __GFP_RETRY_MAYFAIL
: requests as in this patch.

[mhocko@suse.com: reworded changelog]
Link: http://lkml.kernel.org/r/20191007075548.12456-1-mhocko@kernel.org
Fixes: b39d0ee2 ("mm, page_alloc: avoid expensive reclaim when compaction may not succeed")
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NMichal Hocko <mhocko@suse.com>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Make sure allocations from kmem_cache_alloc_bulk() and
kmem_cache_free_bulk() are properly initialized.

Link: http://lkml.kernel.org/r/20191007091605.30530-2-glider@google.comSigned-off-by: NAlexander Potapenko <glider@google.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Thibaut Sautereau <thibaut@sautereau.fr>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

slab_alloc_node() already zeroed out the freelist pointer if
init_on_free was on.  Thibaut Sautereau noticed that the same needs to
be done for kmem_cache_alloc_bulk(), which performs the allocations
separately.

kmem_cache_alloc_bulk() is currently used in two places in the kernel,
so this change is unlikely to have a major performance impact.

SLAB doesn't require a similar change, as auto-initialization makes the
allocator store the freelist pointers off-slab.

Link: http://lkml.kernel.org/r/20191007091605.30530-1-glider@google.com
Fixes: 6471384a ("mm: security: introduce init_on_alloc=1 and init_on_free=1 boot options")
Signed-off-by: NAlexander Potapenko <glider@google.com>
Reported-by: NThibaut Sautereau <thibaut@sautereau.fr>
Reported-by: NKees Cook <keescook@chromium.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Laura Abbott <labbott@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Kmemleak is falsely reporting a leak of the slab allocation in
sctp_stream_init_ext():

  BUG: memory leak
  unreferenced object 0xffff8881114f5d80 (size 96):
   comm "syz-executor934", pid 7160, jiffies 4294993058 (age 31.950s)
   hex dump (first 32 bytes):
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
     00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
   backtrace:
     [<00000000ce7a1326>] kmemleak_alloc_recursive  include/linux/kmemleak.h:55 [inline]
     [<00000000ce7a1326>] slab_post_alloc_hook mm/slab.h:439 [inline]
     [<00000000ce7a1326>] slab_alloc mm/slab.c:3326 [inline]
     [<00000000ce7a1326>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
     [<000000007abb7ac9>] kmalloc include/linux/slab.h:547 [inline]
     [<000000007abb7ac9>] kzalloc include/linux/slab.h:742 [inline]
     [<000000007abb7ac9>] sctp_stream_init_ext+0x2b/0xa0  net/sctp/stream.c:157
     [<0000000048ecb9c1>] sctp_sendmsg_to_asoc+0x946/0xa00  net/sctp/socket.c:1882
     [<000000004483ca2b>] sctp_sendmsg+0x2a8/0x990 net/sctp/socket.c:2102
     [...]

But it's freed later.  Kmemleak misses the allocation because its
pointer is stored in the generic radix tree sctp_stream::out, and the
generic radix tree uses raw pages which aren't tracked by kmemleak.

Fix this by adding the kmemleak hooks to the generic radix tree code.

Link: http://lkml.kernel.org/r/20191004065039.727564-1-ebiggers@kernel.orgSigned-off-by: NEric Biggers <ebiggers@google.com>
Reported-by: <syzbot+7f3b6b106be8dcdcdeec@syzkaller.appspotmail.com>
Reviewed-by: NMarcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Xin Long <lucien.xin@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A long time ago we fixed a similar deadlock in show_slab_objects() [1].
However, it is apparently due to the commits like 01fb58bc ("slab:
remove synchronous synchronize_sched() from memcg cache deactivation
path") and 03afc0e2 ("slab: get_online_mems for
kmem_cache_{create,destroy,shrink}"), this kind of deadlock is back by
just reading files in /sys/kernel/slab which will generate a lockdep
splat below.

Since the "mem_hotplug_lock" here is only to obtain a stable online node
mask while racing with NUMA node hotplug, in the worst case, the results
may me miscalculated while doing NUMA node hotplug, but they shall be
corrected by later reads of the same files.

  WARNING: possible circular locking dependency detected
  ------------------------------------------------------
  cat/5224 is trying to acquire lock:
  ffff900012ac3120 (mem_hotplug_lock.rw_sem){++++}, at:
  show_slab_objects+0x94/0x3a8

  but task is already holding lock:
  b8ff009693eee398 (kn->count#45){++++}, at: kernfs_seq_start+0x44/0xf0

  which lock already depends on the new lock.

  the existing dependency chain (in reverse order) is:

  -> #2 (kn->count#45){++++}:
         lock_acquire+0x31c/0x360
         __kernfs_remove+0x290/0x490
         kernfs_remove+0x30/0x44
         sysfs_remove_dir+0x70/0x88
         kobject_del+0x50/0xb0
         sysfs_slab_unlink+0x2c/0x38
         shutdown_cache+0xa0/0xf0
         kmemcg_cache_shutdown_fn+0x1c/0x34
         kmemcg_workfn+0x44/0x64
         process_one_work+0x4f4/0x950
         worker_thread+0x390/0x4bc
         kthread+0x1cc/0x1e8
         ret_from_fork+0x10/0x18

  -> #1 (slab_mutex){+.+.}:
         lock_acquire+0x31c/0x360
         __mutex_lock_common+0x16c/0xf78
         mutex_lock_nested+0x40/0x50
         memcg_create_kmem_cache+0x38/0x16c
         memcg_kmem_cache_create_func+0x3c/0x70
         process_one_work+0x4f4/0x950
         worker_thread+0x390/0x4bc
         kthread+0x1cc/0x1e8
         ret_from_fork+0x10/0x18

  -> #0 (mem_hotplug_lock.rw_sem){++++}:
         validate_chain+0xd10/0x2bcc
         __lock_acquire+0x7f4/0xb8c
         lock_acquire+0x31c/0x360
         get_online_mems+0x54/0x150
         show_slab_objects+0x94/0x3a8
         total_objects_show+0x28/0x34
         slab_attr_show+0x38/0x54
         sysfs_kf_seq_show+0x198/0x2d4
         kernfs_seq_show+0xa4/0xcc
         seq_read+0x30c/0x8a8
         kernfs_fop_read+0xa8/0x314
         __vfs_read+0x88/0x20c
         vfs_read+0xd8/0x10c
         ksys_read+0xb0/0x120
         __arm64_sys_read+0x54/0x88
         el0_svc_handler+0x170/0x240
         el0_svc+0x8/0xc

  other info that might help us debug this:

  Chain exists of:
    mem_hotplug_lock.rw_sem --> slab_mutex --> kn->count#45

   Possible unsafe locking scenario:

         CPU0                    CPU1
         ----                    ----
    lock(kn->count#45);
                                 lock(slab_mutex);
                                 lock(kn->count#45);
    lock(mem_hotplug_lock.rw_sem);

   *** DEADLOCK ***

  3 locks held by cat/5224:
   #0: 9eff00095b14b2a0 (&p->lock){+.+.}, at: seq_read+0x4c/0x8a8
   #1: 0eff008997041480 (&of->mutex){+.+.}, at: kernfs_seq_start+0x34/0xf0
   #2: b8ff009693eee398 (kn->count#45){++++}, at:
  kernfs_seq_start+0x44/0xf0

  stack backtrace:
  Call trace:
   dump_backtrace+0x0/0x248
   show_stack+0x20/0x2c
   dump_stack+0xd0/0x140
   print_circular_bug+0x368/0x380
   check_noncircular+0x248/0x250
   validate_chain+0xd10/0x2bcc
   __lock_acquire+0x7f4/0xb8c
   lock_acquire+0x31c/0x360
   get_online_mems+0x54/0x150
   show_slab_objects+0x94/0x3a8
   total_objects_show+0x28/0x34
   slab_attr_show+0x38/0x54
   sysfs_kf_seq_show+0x198/0x2d4
   kernfs_seq_show+0xa4/0xcc
   seq_read+0x30c/0x8a8
   kernfs_fop_read+0xa8/0x314
   __vfs_read+0x88/0x20c
   vfs_read+0xd8/0x10c
   ksys_read+0xb0/0x120
   __arm64_sys_read+0x54/0x88
   el0_svc_handler+0x170/0x240
   el0_svc+0x8/0xc

I think it is important to mention that this doesn't expose the
show_slab_objects to use-after-free.  There is only a single path that
might really race here and that is the slab hotplug notifier callback
__kmem_cache_shrink (via slab_mem_going_offline_callback) but that path
doesn't really destroy kmem_cache_node data structures.

[1] http://lkml.iu.edu/hypermail/linux/kernel/1101.0/02850.html

[akpm@linux-foundation.org: add comment explaining why we don't need mem_hotplug_lock]
Link: http://lkml.kernel.org/r/1570192309-10132-1-git-send-email-cai@lca.pw
Fixes: 01fb58bc ("slab: remove synchronous synchronize_sched() from memcg cache deactivation path")
Fixes: 03afc0e2 ("slab: get_online_mems for kmem_cache_{create,destroy,shrink}")
Signed-off-by: NQian Cai <cai@lca.pw>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 37389167 ("mm, page_owner: keep owner info when freeing the
page") has introduced a flag PAGE_EXT_OWNER_ACTIVE to indicate that page
is tracked as being allocated.  Kirril suggested naming it
PAGE_EXT_OWNER_ALLOCATED to make it more clear, as "active is somewhat
loaded term for a page".

Link: http://lkml.kernel.org/r/20190930122916.14969-4-vbabka@suse.czSigned-off-by: NVlastimil Babka <vbabka@suse.cz>
Suggested-by: NKirill A. Shutemov <kirill@shutemov.name>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Walter Wu <walter-zh.wu@mediatek.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 8974558f ("mm, page_owner, debug_pagealloc: save and dump
freeing stack trace") enhanced page_owner to also store freeing stack
trace, when debug_pagealloc is also enabled.  KASAN would also like to
do this [1] to improve error reports to debug e.g. UAF issues.

Kirill has suggested that the freeing stack trace saving should be also
possible to be enabled separately from KASAN or debug_pagealloc, i.e.
with an extra boot option.  Qian argued that we have enough options
already, and avoiding the extra overhead is not worth the complications
in the case of a debugging option.  Kirill noted that the extra stack
handle in struct page_owner requires 0.1% of memory.

This patch therefore enables free stack saving whenever page_owner is
enabled, regardless of whether debug_pagealloc or KASAN is also enabled.
KASAN kernels booted with page_owner=on will thus benefit from the
improved error reports.

[1] https://bugzilla.kernel.org/show_bug.cgi?id=203967

[vbabka@suse.cz: v3]
  Link: http://lkml.kernel.org/r/20191007091808.7096-3-vbabka@suse.cz
Link: http://lkml.kernel.org/r/20190930122916.14969-3-vbabka@suse.czSigned-off-by: NVlastimil Babka <vbabka@suse.cz>
Reviewed-by: NQian Cai <cai@lca.pw>
Suggested-by: NDmitry Vyukov <dvyukov@google.com>
Suggested-by: NWalter Wu <walter-zh.wu@mediatek.com>
Suggested-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Suggested-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Suggested-by: NQian Cai <cai@lca.pw>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "followups to debug_pagealloc improvements through
page_owner", v3.

These are followups to [1] which made it to Linus meanwhile.  Patches 1
and 3 are based on Kirill's review, patch 2 on KASAN request [2].  It
would be nice if all of this made it to 5.4 with [1] already there (or
at least Patch 1).

This patch (of 3):

As noted by Kirill, commit 7e2f2a0c ("mm, page_owner: record page
owner for each subpage") has introduced an off-by-one error in
__set_page_owner_handle() when looking up page_ext for subpages.  As a
result, the head page page_owner info is set twice, while for the last
tail page, it's not set at all.

Fix this and also make the code more efficient by advancing the page_ext
pointer we already have, instead of calling lookup_page_ext() for each
subpage.  Since the full size of struct page_ext is not known at compile
time, we can't use a simple page_ext++ statement, so introduce a
page_ext_next() inline function for that.

Link: http://lkml.kernel.org/r/20190930122916.14969-2-vbabka@suse.cz
Fixes: 7e2f2a0c ("mm, page_owner: record page owner for each subpage")
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Reported-by: NKirill A. Shutemov <kirill@shutemov.name>
Reported-by: NMiles Chen <miles.chen@mediatek.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Walter Wu <walter-zh.wu@mediatek.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This breaks booting from sata_sil24 with the recent DMA change.
According to James Bottomley this was in to improve performance by
kicking the device into 32 bit descriptors, which are usually more
efficient, especially with older dual descriptor format cards like we
have on parisc systems.
Remove it for now to make DMA working again.

Fixes: dcc02c19 ("sata_sil24: use dma_set_mask_and_coherent")
Signed-off-by: NSven Schnelle <svens@stackframe.org>
Signed-off-by: NHelge Deller <deller@gmx.de>

Sven noticed that calling ioremap() and iounmap() multiple times leads
to a vmap memory leak:
	vmap allocation for size 4198400 failed:
	use vmalloc=<size> to increase size

It seems we missed calling vunmap() in iounmap().
Signed-off-by: NHelge Deller <deller@gmx.de>
Noticed-by: NSven Schnelle <svens@stackframe.org>
Cc: <stable@vger.kernel.org> # v3.16+

Reported-by: NSedat Dilek <sedat.dilek@gmail.com>
Suggested-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NHelge Deller <deller@gmx.de>

Signed-off-by: NHelge Deller <deller@gmx.de>

Before reading the Extended Size field, we should ensure it fits in
the DMI record. There is already a record length check but it does
not cover that field.

It would take a seriously corrupted DMI table to hit that bug, so no
need to worry, but we should still fix it.
Signed-off-by: NJean Delvare <jdelvare@suse.de>
Fixes: 6deae96b ("firmware, DMI: Add function to look up a handle and return DIMM size")
Cc: Tony Luck <tony.luck@intel.com>
Cc: Borislav Petkov <bp@suse.de>

In case of an error (e.g. memory pool too small), kmemleak disables
itself and cleans up the already allocated metadata objects. However, if
this happens early before the RCU callback mechanism is available,
put_object() skips call_rcu() and frees the object directly. This is not
safe with the RCU list traversal in __kmemleak_do_cleanup().

Change the list traversal in __kmemleak_do_cleanup() to
list_for_each_entry_safe() and remove the rcu_read_{lock,unlock} since
the kmemleak is already disabled at this point. In addition, avoid an
unnecessary metadata object rb-tree look-up since it already has the
struct kmemleak_object pointer.

Fixes: c5665868 ("mm: kmemleak: use the memory pool for early allocations")
Reported-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Reported-by: NMarc Dionne <marc.c.dionne@gmail.com>
Reported-by: NTed Ts'o <tytso@mit.edu>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Pull tracing fixes from Steven Rostedt:
 "A few tracing fixes:

   - Remove lockdown from tracefs itself and moved it to the trace
     directory. Have the open functions there do the lockdown checks.

   - Fix a few races with opening an instance file and the instance
     being deleted (Discovered during the lockdown updates). Kept
     separate from the clean up code such that they can be backported to
     stable easier.

   - Clean up and consolidated the checks done when opening a trace
     file, as there were multiple checks that need to be done, and it
     did not make sense having them done in each open instance.

   - Fix a regression in the record mcount code.

   - Small hw_lat detector tracer fixes.

   - A trace_pipe read fix due to not initializing trace_seq"

* tag 'trace-v5.4-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing: Initialize iter->seq after zeroing in tracing_read_pipe()
  tracing/hwlat: Don't ignore outer-loop duration when calculating max_latency
  tracing/hwlat: Report total time spent in all NMIs during the sample
  recordmcount: Fix nop_mcount() function
  tracing: Do not create tracefs files if tracefs lockdown is in effect
  tracing: Add locked_down checks to the open calls of files created for tracefs
  tracing: Add tracing_check_open_get_tr()
  tracing: Have trace events system open call tracing_open_generic_tr()
  tracing: Get trace_array reference for available_tracers files
  ftrace: Get a reference counter for the trace_array on filter files
  tracefs: Revert ccbd54ff ("tracefs: Restrict tracefs when the kernel is locked down")

Merge tag 'hwmon-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging

Pull hwmon fixes from Guenter Roeck:

 - Update/fix inspur-ipsps1 and k10temp Documentation

 - Fix nct7904 driver

 - Fix HWMON_P_MIN_ALARM mask in hwmon core

* tag 'hwmon-for-v5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
  hwmon: docs: Extend inspur-ipsps1 title underline
  hwmon: (nct7904) Add array fan_alarm and vsen_alarm to store the alarms in nct7904_data struct.
  docs: hwmon: Include 'inspur-ipsps1.rst' into docs
  hwmon: Fix HWMON_P_MIN_ALARM mask
  hwmon: (k10temp) Update documentation and add temp2_input info
  hwmon: (nct7904) Fix the incorrect value of vsen_mask in nct7904_data struct

Pull MTD fixes from Richard Weinberger:
 "Two fixes for MTD:

   - spi-nor: Fix for a regression in write_sr()

   - rawnand: Regression fix for the au1550nd driver"

* tag 'fixes-for-5.4-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux:
  mtd: rawnand: au1550nd: Fix au_read_buf16() prototype
  mtd: spi-nor: Fix direction of the write_sr() transfer

Pull io_uring fix from Jens Axboe:
 "Single small fix for a regression in the sequence logic for linked
  commands"

* tag 'for-linus-20191012' of git://git.kernel.dk/linux-block:
  io_uring: fix sequence logic for timeout requests

When device stop was moved out of reset, test device wasn't updated to
stop before reset, this resulted in a use after free.  Fix by invoking
stop appropriately.

Fixes: b211616d ("vhost: move -net specific code out")
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

Fixes test module build.
Reported-by: NJan Kiszka <jan.kiszka@web.de>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

A customer reported the following softlockup:

[899688.160002] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [test.sh:16464]
[899688.160002] CPU: 0 PID: 16464 Comm: test.sh Not tainted 4.12.14-6.23-azure #1 SLE12-SP4
[899688.160002] RIP: 0010:up_write+0x1a/0x30
[899688.160002] Kernel panic - not syncing: softlockup: hung tasks
[899688.160002] RIP: 0010:up_write+0x1a/0x30
[899688.160002] RSP: 0018:ffffa86784d4fde8 EFLAGS: 00000257 ORIG_RAX: ffffffffffffff12
[899688.160002] RAX: ffffffff970fea00 RBX: 0000000000000001 RCX: 0000000000000000
[899688.160002] RDX: ffffffff00000001 RSI: 0000000000000080 RDI: ffffffff970fea00
[899688.160002] RBP: ffffffffffffffff R08: ffffffffffffffff R09: 0000000000000000
[899688.160002] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8b59014720d8
[899688.160002] R13: ffff8b59014720c0 R14: ffff8b5901471090 R15: ffff8b5901470000
[899688.160002]  tracing_read_pipe+0x336/0x3c0
[899688.160002]  __vfs_read+0x26/0x140
[899688.160002]  vfs_read+0x87/0x130
[899688.160002]  SyS_read+0x42/0x90
[899688.160002]  do_syscall_64+0x74/0x160

It caught the process in the middle of trace_access_unlock(). There is
no loop. So, it must be looping in the caller tracing_read_pipe()
via the "waitagain" label.

Crashdump analyze uncovered that iter->seq was completely zeroed
at this point, including iter->seq.seq.size. It means that
print_trace_line() was never able to print anything and
there was no forward progress.

The culprit seems to be in the code:

	/* reset all but tr, trace, and overruns */
	memset(&iter->seq, 0,
	       sizeof(struct trace_iterator) -
	       offsetof(struct trace_iterator, seq));

It was added by the commit 53d0aa77 ("ftrace:
add logic to record overruns"). It was v2.6.27-rc1.
It was the time when iter->seq looked like:

     struct trace_seq {
	unsigned char		buffer[PAGE_SIZE];
	unsigned int		len;
     };

There was no "size" variable and zeroing was perfectly fine.

The solution is to reinitialize the structure after or without
zeroing.

Link: http://lkml.kernel.org/r/20191011142134.11997-1-pmladek@suse.comSigned-off-by: NPetr Mladek <pmladek@suse.com>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

max_latency is intended to record the maximum ever observed hardware
latency, which may occur in either part of the loop (inner/outer). So
we need to also consider the outer-loop sample when updating
max_latency.

Link: http://lkml.kernel.org/r/157073345463.17189.18124025522664682811.stgit@srivatsa-ubuntu

Fixes: e7c15cd8 ("tracing: Added hardware latency tracer")
Cc: stable@vger.kernel.org
Signed-off-by: NSrivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

nmi_total_ts is supposed to record the total time spent in *all* NMIs
that occur on the given CPU during the (active portion of the)
sampling window. However, the code seems to be overwriting this
variable for each NMI, thereby only recording the time spent in the
most recent NMI. Fix it by accumulating the duration instead.

Link: http://lkml.kernel.org/r/157073343544.17189.13911783866738671133.stgit@srivatsa-ubuntu

Fixes: 7b2c8625 ("tracing: Add NMI tracing in hwlat detector")
Cc: stable@vger.kernel.org
Signed-off-by: NSrivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>

The removal of the longjmp code in recordmcount.c mistakenly made the return
of make_nop() being negative an exit of nop_mcount(). It should not exit the
routine, but instead just not process that part of the code. By exiting with
an error code, it would cause the update of recordmcount to fail some files
which would fail the build if ftrace function tracing was enabled.

Link: http://lkml.kernel.org/r/20191009110538.5909fec6@gandalf.local.homeReported-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Tested-by: NUwe Kleine-König <u.kleine-koenig@pengutronix.de>
Fixes: 3f1df120 ("recordmcount: Rewrite error/success handling")
Signed-off-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>