Commit 612e4493 ("mm: workingset: eviction buckets for bigmem/lowbit
machines") added a printk without a log level.  Quieten it by using
pr_info().

Link: http://lkml.kernel.org/r/1466982072-29836-2-git-send-email-anton@ozlabs.orgSigned-off-by: NAnton Blanchard <anton@samba.org>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The VM_BUG_ON_PAGE in page_move_anon_rmap() is more trouble than it's
worth: the syzkaller fuzzer hit it again.  It's still wrong for some THP
cases, because linear_page_index() was never intended to apply to
addresses before the start of a vma.

That's easily fixed with a signed long cast inside linear_page_index();
and Dmitry has tested such a patch, to verify the false positive.  But
why extend linear_page_index() just for this case? when the avoidance in
page_move_anon_rmap() has already grown ugly, and there's no reason for
the check at all (nothing else there is using address or index).

Remove address arg from page_move_anon_rmap(), remove VM_BUG_ON_PAGE,
remove CONFIG_DEBUG_VM PageTransHuge adjustment.

And one more thing: should the compound_head(page) be done inside or
outside page_move_anon_rmap()? It's usually pushed down to the lowest
level nowadays (and mm/memory.c shows no other explicit use of it), so I
think it's better done in page_move_anon_rmap() than by caller.

Fixes: 0798d3c0 ("mm: thp: avoid false positive VM_BUG_ON_PAGE in page_move_anon_rmap()")
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1607120444540.12528@eggly.anvilsSigned-off-by: NHugh Dickins <hughd@google.com>
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: <stable@vger.kernel.org>	[4.5+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The previous patch addresses the race between split_huge_pmd_address()
and someone changing the pmd.  The fix is only for splitting of normal
thp (i.e.  pmd-mapped thp,) and for splitting of pte-mapped thp there
still is the similar race.

For splitting pte-mapped thp, the pte's conversion is done by
try_to_unmap_one(TTU_MIGRATION).  This function checks
page_check_address() to get the target pte, but it can return NULL under
some race, leading to VM_BUG_ON() in freeze_page().  Fortunately,
page_check_address() already has an argument to decide whether we do a
quick/racy check or not, so let's flip it when called from
freeze_page().

Link: http://lkml.kernel.org/r/1466990929-7452-2-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I found a race condition triggering VM_BUG_ON() in freeze_page(), when
running a testcase with 3 processes:
  - process 1: keep writing thp,
  - process 2: keep clearing soft-dirty bits from virtual address of process 1
  - process 3: call migratepages for process 1,

The kernel message is like this:

  kernel BUG at /src/linux-dev/mm/huge_memory.c:3096!
  invalid opcode: 0000 [#1] SMP
  Modules linked in: cfg80211 rfkill crc32c_intel ppdev serio_raw pcspkr virtio_balloon virtio_console parport_pc parport pvpanic acpi_cpufreq tpm_tis tpm i2c_piix4 virtio_blk virtio_net ata_generic pata_acpi floppy virtio_pci virtio_ring virtio
  CPU: 0 PID: 28863 Comm: migratepages Not tainted 4.6.0-v4.6-160602-0827-+ #2
  Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
  task: ffff880037320000 ti: ffff88007cdd0000 task.ti: ffff88007cdd0000
  RIP: 0010:[<ffffffff811f8e06>]  [<ffffffff811f8e06>] split_huge_page_to_list+0x496/0x590
  RSP: 0018:ffff88007cdd3b70  EFLAGS: 00010202
  RAX: 0000000000000001 RBX: ffff88007c7b88c0 RCX: 0000000000000000
  RDX: 0000000000000000 RSI: 0000000700000200 RDI: ffffea0003188000
  RBP: ffff88007cdd3bb8 R08: 0000000000000001 R09: 00003ffffffff000
  R10: ffff880000000000 R11: ffffc000001fffff R12: ffffea0003188000
  R13: ffffea0003188000 R14: 0000000000000000 R15: 0400000000000080
  FS:  00007f8ec241d740(0000) GS:ffff88007dc00000(0000) knlGS:0000000000000000             CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f8ec1f3ed20 CR3: 000000003707b000 CR4: 00000000000006f0
  Call Trace:
    ? list_del+0xd/0x30
    queue_pages_pte_range+0x4d1/0x590
    __walk_page_range+0x204/0x4e0
    walk_page_range+0x71/0xf0
    queue_pages_range+0x75/0x90
    ? queue_pages_hugetlb+0x190/0x190
    ? new_node_page+0xc0/0xc0
    ? change_prot_numa+0x40/0x40
    migrate_to_node+0x71/0xd0
    do_migrate_pages+0x1c3/0x210
    SyS_migrate_pages+0x261/0x290
    entry_SYSCALL_64_fastpath+0x1a/0xa4
  Code: e8 b0 87 fb ff 0f 0b 48 c7 c6 30 32 9f 81 e8 a2 87 fb ff 0f 0b 48 c7 c6 b8 46 9f 81 e8 94 87 fb ff 0f 0b 85 c0 0f 84 3e fd ff ff <0f> 0b 85 c0 0f 85 a6 00 00 00 48 8b 75 c0 4c 89 f7 41 be f0 ff
  RIP   split_huge_page_to_list+0x496/0x590

I'm not sure of the full scenario of the reproduction, but my debug
showed that split_huge_pmd_address(freeze=true) returned without running
main code of pmd splitting because pmd_present(*pmd) in precheck somehow
returned 0.  If this happens, the subsequent try_to_unmap() fails and
returns non-zero (because page_mapcount() still > 0), and finally
VM_BUG_ON() fires.  This patch tries to fix it by prechecking pmd state
inside ptl.

Link: http://lkml.kernel.org/r/1466990929-7452-1-git-send-email-n-horiguchi@ah.jp.nec.comSigned-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

early_page_uninitialised looks up an arbitrary PFN.  While a machine
without node 0 will boot with "mm, page_alloc: Always return a valid
node from early_pfn_to_nid", it works because it assumes that nodes are
always in PFN order.  This is not guaranteed so this patch adds
robustness by always checking if the node being checked is online.

Link: http://lkml.kernel.org/r/1468008031-3848-4-git-send-email-mgorman@techsingularity.netSigned-off-by: NMel Gorman <mgorman@techsingularity.net>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[4.2+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

early_pfn_to_nid can return node 0 if a PFN is invalid on machines that
has no node 0.  A machine with only node 1 was observed to crash with
the following message:

   BUG: unable to handle kernel paging request at 000000000002a3c8
   PGD 0
   Modules linked in:
   Hardware name: Supermicro H8DSP-8/H8DSP-8, BIOS 080011  06/30/2006
   task: ffffffff81c0d500 ti: ffffffff81c00000 task.ti: ffffffff81c00000
   RIP: reserve_bootmem_region+0x6a/0xef
   CR2: 000000000002a3c8 CR3: 0000000001c06000 CR4: 00000000000006b0
   Call Trace:
      free_all_bootmem+0x4b/0x12a
      mem_init+0x70/0xa3
      start_kernel+0x25b/0x49b

The problem is that early_page_uninitialised uses the early_pfn_to_nid
helper which returns node 0 for invalid PFNs.  No caller of
early_pfn_to_nid cares except early_page_uninitialised.  This patch has
early_pfn_to_nid always return a valid node.

Link: http://lkml.kernel.org/r/1468008031-3848-3-git-send-email-mgorman@techsingularity.netSigned-off-by: NMel Gorman <mgorman@techsingularity.net>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[4.2+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are two bugs on qlist_move_cache().  One is that qlist's tail
isn't set properly.  curr->next can be NULL since it is singly linked
list and NULL value on tail is invalid if there is one item on qlist.
Another one is that if cache is matched, qlist_put() is called and it
will set curr->next to NULL.  It would cause to stop the loop
prematurely.

These problems come from complicated implementation so I'd like to
re-implement it completely.  Implementation in this patch is really
simple.  Iterate all qlist_nodes and put them to appropriate list.

Unfortunately, I got this bug sometime ago and lose oops message.  But,
the bug looks trivial and no need to attach oops.

Fixes: 55834c59 ("mm: kasan: initial memory quarantine implementation")
Link: http://lkml.kernel.org/r/1467766348-22419-1-git-send-email-iamjoonsoo.kim@lge.comSigned-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Reviewed-by: NDmitry Vyukov <dvyukov@google.com>
Acked-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: NAlexander Potapenko <glider@google.com>
Cc: Kuthonuzo Luruo <poll.stdin@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

madvise_free_huge_pmd should return 0 if the fallback PTE operations are
required.  In madvise_free_huge_pmd, if part pages of THP are discarded,
the THP will be split and fallback PTE operations should be used if
splitting succeeds.  But the original code will make fallback PTE
operations skipped, after splitting succeeds.  Fix that via make
madvise_free_huge_pmd return 0 after splitting successfully, so that the
fallback PTE operations will be done.

Link: http://lkml.kernel.org/r/1467135452-16688-1-git-send-email-ying.huang@intel.comSigned-off-by: N"Huang, Ying" <ying.huang@intel.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Jerome Marchand <jmarchan@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Ebru Akagunduz <ebru.akagunduz@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It's possible to isolate some freepages in a pageblock and then fail
split_free_page() due to the low watermark check.  In this case, we hit
VM_BUG_ON() because the freeing scanner terminated early without a
contended lock or enough freepages.

This should never have been a VM_BUG_ON() since it's not a fatal
condition.  It should have been a VM_WARN_ON() at best, or even handled
gracefully.

Regardless, we need to terminate anytime the full pageblock scan was not
done.  The logic belongs in isolate_freepages_block(), so handle its
state gracefully by terminating the pageblock loop and making a note to
restart at the same pageblock next time since it was not possible to
complete the scan this time.

[rientjes@google.com: don't rescan pages in a pageblock]
  Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1607111244150.83138@chino.kir.corp.google.com
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1606291436300.145590@chino.kir.corp.google.comSigned-off-by: NDavid Rientjes <rientjes@google.com>
Reported-by: NMinchan Kim <minchan@kernel.org>
Tested-by: NMinchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The well-spotted fallocate undo fix is good in most cases, but not when
fallocate failed on the very first page.  index 0 then passes lend -1
to shmem_undo_range(), and that has two bad effects: (a) that it will
undo every fallocation throughout the file, unrestricted by the current
range; but more importantly (b) it can cause the undo to hang, because
lend -1 is treated as truncation, which makes it keep on retrying until
every page has gone, but those already fully instantiated will never go
away.  Big thank you to xfstests generic/269 which demonstrates this.

Fixes: b9b4bb26 ("tmpfs: don't undo fallocate past its last page")
Cc: stable@vger.kernel.org
Signed-off-by: NHugh Dickins <hughd@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We have dereferenced page_ext before checking it.  Lets check it first
and then used it.

Fixes: f86e4271 ("mm: check the return value of lookup_page_ext for all call sites")
Link: http://lkml.kernel.org/r/1465249059-7883-1-git-send-email-sudipm.mukherjee@gmail.comSigned-off-by: NSudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

If the memory compaction free scanner cannot successfully split a free
page (only possible due to per-zone low watermark), terminate the free
scanner rather than continuing to scan memory needlessly.  If the
watermark is insufficient for a free page of order <= cc->order, then
terminate the scanner since all future splits will also likely fail.

This prevents the compaction freeing scanner from scanning all memory on
very large zones (very noticeable for zones > 128GB, for instance) when
all splits will likely fail while holding zone->lock.

compaction_alloc() iterating a 128GB zone has been benchmarked to take
over 400ms on some systems whereas any free page isolated and ready to
be split ends up failing in split_free_page() because of the low
watermark check and thus the iteration continues.

The next time compaction occurs, the freeing scanner will likely start
at the end of the zone again since no success was made previously and we
get the same lengthy iteration until the zone is brought above the low
watermark.  All thp page faults can take >400ms in such a state without
this fix.

Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1606211820350.97086@chino.kir.corp.google.comSigned-off-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When kmemleak dumps contents of leaked objects it reads whole objects
regardless of user-requested size.  This upsets KASAN.  Disable KASAN
checks around object dump.

Link: http://lkml.kernel.org/r/1466617631-68387-1-git-send-email-dvyukov@google.comSigned-off-by: NDmitry Vyukov <dvyukov@google.com>
Acked-by: NCatalin Marinas <catalin.marinas@arm.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

While working on s390 support for gigantic hugepages I ran into the
following "Bad page state" warning when freeing gigantic pages:

  BUG: Bad page state in process bash  pfn:580001
  page:000003d116000040 count:0 mapcount:0 mapping:ffffffff00000000 index:0x0
  flags: 0x7fffc0000000000()
  page dumped because: non-NULL mapping

This is because page->compound_mapcount, which is part of a union with
page->mapping, is initialized with -1 in prep_compound_gigantic_page(),
and not cleared again during destroy_compound_gigantic_page().  Fix this
by clearing the compound_mapcount in destroy_compound_gigantic_page()
before clearing compound_head.

Interestingly enough, the warning will not show up on x86_64, although
this should not be architecture specific.  Apparently there is an
endianness issue, combined with the fact that the union contains both a
64 bit ->mapping pointer and a 32 bit atomic_t ->compound_mapcount as
members.  The resulting bogus page->mapping on x86_64 therefore contains
00000000ffffffff instead of ffffffff00000000 on s390, which will falsely
trigger the PageAnon() check in free_pages_prepare() because
page->mapping & PAGE_MAPPING_ANON is true on little-endian architectures
like x86_64 in this case (the page is not compound anymore,
->compound_head was already cleared before).  As a result, page->mapping
will be cleared before doing the checks in free_pages_check().

Not sure if the bogus "PageAnon() returning true" on x86_64 for the
first tail page of a gigantic page (at this stage) has other theoretical
implications, but they would also be fixed with this patch.

Link: http://lkml.kernel.org/r/1466612719-5642-1-git-send-email-gerald.schaefer@de.ibm.comSigned-off-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently we can have compound pages held on per cpu pagevecs, which
leads to a lot of memory unavailable for reclaim when needed.  In the
systems with hundreads of processors it can be GBs of memory.

On of the way of reproducing the problem is to not call munmap
explicitly on all mapped regions (i.e.  after receiving SIGTERM).  After
that some pages (with THP enabled also huge pages) may end up on
lru_add_pvec, example below.

  void main() {
  #pragma omp parallel
  {
	size_t size = 55 * 1000 * 1000; // smaller than  MEM/CPUS
	void *p = mmap(NULL, size, PROT_READ | PROT_WRITE,
		MAP_PRIVATE | MAP_ANONYMOUS , -1, 0);
	if (p != MAP_FAILED)
		memset(p, 0, size);
	//munmap(p, size); // uncomment to make the problem go away
  }
  }

When we run it with THP enabled it will leave significant amount of
memory on lru_add_pvec.  This memory will be not reclaimed if we hit
OOM, so when we run above program in a loop:

	for i in `seq 100`; do ./a.out; done

many processes (95% in my case) will be killed by OOM.

The primary point of the LRU add cache is to save the zone lru_lock
contention with a hope that more pages will belong to the same zone and
so their addition can be batched.  The huge page is already a form of
batched addition (it will add 512 worth of memory in one go) so skipping
the batching seems like a safer option when compared to a potential
excess in the caching which can be quite large and much harder to fix
because lru_add_drain_all is way to expensive and it is not really clear
what would be a good moment to call it.

Similarly we can reproduce the problem on lru_deactivate_pvec by adding:
madvise(p, size, MADV_FREE); after memset.

This patch flushes lru pvecs on compound page arrival making the problem
less severe - after applying it kill rate of above example drops to 0%,
due to reducing maximum amount of memory held on pvec from 28MB (with
THP) to 56kB per CPU.
Suggested-by: NMichal Hocko <mhocko@suse.com>
Link: http://lkml.kernel.org/r/1466180198-18854-1-git-send-email-lukasz.odzioba@intel.comSigned-off-by: NLukasz Odzioba <lukasz.odzioba@intel.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Vladimir Davydov <vdavydov@parallels.com>
Cc: Ming Li <mingli199x@qq.com>
Cc: Minchan Kim <minchan@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>

mem_cgroup_css_alloc() was returning NULL on failure while cgroup core
expected it to return an ERR_PTR value leading to the following NULL
deref after a css allocation failure.  Fix it by return
ERR_PTR(-ENOMEM) instead.  I'll also update cgroup core so that it
can handle NULL returns.

  mkdir: page allocation failure: order:6, mode:0x240c0c0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO)
  CPU: 0 PID: 8738 Comm: mkdir Not tainted 4.7.0-rc3+ #123
  ...
  Call Trace:
    dump_stack+0x68/0xa1
    warn_alloc_failed+0xd6/0x130
    __alloc_pages_nodemask+0x4c6/0xf20
    alloc_pages_current+0x66/0xe0
    alloc_kmem_pages+0x14/0x80
    kmalloc_order_trace+0x2a/0x1a0
    __kmalloc+0x291/0x310
    memcg_update_all_caches+0x6c/0x130
    mem_cgroup_css_alloc+0x590/0x610
    cgroup_apply_control_enable+0x18b/0x370
    cgroup_mkdir+0x1de/0x2e0
    kernfs_iop_mkdir+0x55/0x80
    vfs_mkdir+0xb9/0x150
    SyS_mkdir+0x66/0xd0
    do_syscall_64+0x53/0x120
    entry_SYSCALL64_slow_path+0x25/0x25
  ...
  BUG: unable to handle kernel NULL pointer dereference at 00000000000000d0
  IP:  init_and_link_css+0x37/0x220
  PGD 34b1e067 PUD 3a109067 PMD 0
  Oops: 0002 [#1] SMP
  Modules linked in:
  CPU: 0 PID: 8738 Comm: mkdir Not tainted 4.7.0-rc3+ #123
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.2-20160422_131301-anatol 04/01/2014
  task: ffff88007cbc5200 ti: ffff8800666d4000 task.ti: ffff8800666d4000
  RIP: 0010:[<ffffffff810f2ca7>]  [<ffffffff810f2ca7>] init_and_link_css+0x37/0x220
  RSP: 0018:ffff8800666d7d90  EFLAGS: 00010246
  RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
  RDX: ffffffff810f2499 RSI: 0000000000000000 RDI: 0000000000000008
  RBP: ffff8800666d7db8 R08: 0000000000000003 R09: 0000000000000000
  R10: 0000000000000001 R11: 0000000000000000 R12: ffff88005a5fb400
  R13: ffffffff81f0f8a0 R14: ffff88005a5fb400 R15: 0000000000000010
  FS:  00007fc944689700(0000) GS:ffff88007fc00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f3aed0d2b80 CR3: 000000003a1e8000 CR4: 00000000000006f0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
    cgroup_apply_control_enable+0x1ac/0x370
    cgroup_mkdir+0x1de/0x2e0
    kernfs_iop_mkdir+0x55/0x80
    vfs_mkdir+0xb9/0x150
    SyS_mkdir+0x66/0xd0
    do_syscall_64+0x53/0x120
    entry_SYSCALL64_slow_path+0x25/0x25
  Code: 89 f5 48 89 fb 49 89 d4 48 83 ec 08 8b 05 72 3b d8 00 85 c0 0f 85 60 01 00 00 4c 89 e7 e8 72 f7 ff ff 48 8d 7b 08 48 89 d9 31 c0 <48> c7 83 d0 00 00 00 00 00 00 00 48 83 e7 f8 48 29 f9 81 c1 d8
  RIP   init_and_link_css+0x37/0x220
   RSP <ffff8800666d7d90>
  CR2: 00000000000000d0
  ---[ end trace a2d8836ae1e852d1 ]---

Link: http://lkml.kernel.org/r/20160621165740.GJ3262@mtj.duckdns.orgSigned-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NJohannes Weiner <hannes@cmpxchg.org>
Reviewed-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mem_cgroup_migrate() uses local_irq_disable/enable() but can be called
with irq disabled from migrate_page_copy().  This ends up enabling irq
while holding a irq context lock triggering the following lockdep
warning.  Fix it by using irq_save/restore instead.

  =================================
  [ INFO: inconsistent lock state ]
  4.7.0-rc1+ #52 Tainted: G        W
  ---------------------------------
  inconsistent {IN-SOFTIRQ-W} -> {SOFTIRQ-ON-W} usage.
  kcompactd0/151 [HC0[0]:SC0[0]:HE1:SE1] takes:
   (&(&ctx->completion_lock)->rlock){+.?.-.}, at: [<000000000038fd96>] aio_migratepage+0x156/0x1e8
  {IN-SOFTIRQ-W} state was registered at:
     __lock_acquire+0x5b6/0x1930
     lock_acquire+0xee/0x270
     _raw_spin_lock_irqsave+0x66/0xb0
     aio_complete+0x98/0x328
     dio_complete+0xe4/0x1e0
     blk_update_request+0xd4/0x450
     scsi_end_request+0x48/0x1c8
     scsi_io_completion+0x272/0x698
     blk_done_softirq+0xca/0xe8
     __do_softirq+0xc8/0x518
     irq_exit+0xee/0x110
     do_IRQ+0x6a/0x88
     io_int_handler+0x11a/0x25c
     __mutex_unlock_slowpath+0x144/0x1d8
     __mutex_unlock_slowpath+0x140/0x1d8
     kernfs_iop_permission+0x64/0x80
     __inode_permission+0x9e/0xf0
     link_path_walk+0x6e/0x510
     path_lookupat+0xc4/0x1a8
     filename_lookup+0x9c/0x160
     user_path_at_empty+0x5c/0x70
     SyS_readlinkat+0x68/0x140
     system_call+0xd6/0x270
  irq event stamp: 971410
  hardirqs last  enabled at (971409):  migrate_page_move_mapping+0x3ea/0x588
  hardirqs last disabled at (971410):  _raw_spin_lock_irqsave+0x3c/0xb0
  softirqs last  enabled at (970526):  __do_softirq+0x460/0x518
  softirqs last disabled at (970519):  irq_exit+0xee/0x110

  other info that might help us debug this:
   Possible unsafe locking scenario:

	 CPU0
	 ----
    lock(&(&ctx->completion_lock)->rlock);
    <Interrupt>
      lock(&(&ctx->completion_lock)->rlock);

    *** DEADLOCK ***

  3 locks held by kcompactd0/151:
   #0:  (&(&mapping->private_lock)->rlock){+.+.-.}, at:  aio_migratepage+0x42/0x1e8
   #1:  (&ctx->ring_lock){+.+.+.}, at:  aio_migratepage+0x5a/0x1e8
   #2:  (&(&ctx->completion_lock)->rlock){+.?.-.}, at:  aio_migratepage+0x156/0x1e8

  stack backtrace:
  CPU: 20 PID: 151 Comm: kcompactd0 Tainted: G        W       4.7.0-rc1+ #52
  Call Trace:
    show_trace+0xea/0xf0
    show_stack+0x72/0xf0
    dump_stack+0x9a/0xd8
    print_usage_bug.part.27+0x2d4/0x2e8
    mark_lock+0x17e/0x758
    mark_held_locks+0xa2/0xd0
    trace_hardirqs_on_caller+0x140/0x1c0
    mem_cgroup_migrate+0x266/0x370
    aio_migratepage+0x16a/0x1e8
    move_to_new_page+0xb0/0x260
    migrate_pages+0x8f4/0x9f0
    compact_zone+0x4dc/0xdc8
    kcompactd_do_work+0x1aa/0x358
    kcompactd+0xba/0x2c8
    kthread+0x10a/0x110
    kernel_thread_starter+0x6/0xc
    kernel_thread_starter+0x0/0xc
  INFO: lockdep is turned off.

Link: http://lkml.kernel.org/r/20160620184158.GO3262@mtj.duckdns.org
Link: http://lkml.kernel.org/g/5767CFE5.7080904@de.ibm.com
Fixes: 74485cf2 ("mm: migrate: consolidate mem_cgroup_migrate() calls")
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NMichal Hocko <mhocko@suse.com>
Reviewed-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Cc: <stable@vger.kernel.org>	[4.5+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We account HugeTLB's shared page table to all processes who share it.
The accounting happens during huge_pmd_share().

If somebody populates pud entry under us, we should decrease pagetable's
refcount and decrease nr_pmds of the process.

By mistake, I increase nr_pmds again in this case.  :-/ It will lead to
"BUG: non-zero nr_pmds on freeing mm: 2" on process' exit.

Let's fix this by increasing nr_pmds only when we're sure that the page
table will be used.

Link: http://lkml.kernel.org/r/20160617122506.GC6534@node.shutemov.name
Fixes: dc6c9a35 ("mm: account pmd page tables to the process")
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: Nzhongjiang <zhongjiang@huawei.com>
Reviewed-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This reverts commit d0834a6c.

After revert of 5c0a85fa ("mm: make faultaround produce old ptes")
faultaround doesn't have dependencies on hardware accessed bit, so let's
revert this one too.

Link: http://lkml.kernel.org/r/1465893750-44080-3-git-send-email-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: N"Huang, Ying" <ying.huang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This reverts commit 5c0a85fa.

The commit causes ~6% regression in unixbench.

Let's revert it for now and consider other solution for reclaim problem
later.

Link: http://lkml.kernel.org/r/1465893750-44080-2-git-send-email-kirill.shutemov@linux.intel.comSigned-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: N"Huang, Ying" <ying.huang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit d0164adc ("mm, page_alloc: distinguish between being unable
to sleep, unwilling to sleep and avoiding waking kswapd") modified
__GFP_WAIT to explicitly identify the difference between atomic callers
and those that were unwilling to sleep.  Later the definition was
removed entirely.

The GFP_RECLAIM_MASK is the set of flags that affect watermark checking
and reclaim behaviour but __GFP_ATOMIC was never added.  Without it,
atomic users of the slab allocator strip the __GFP_ATOMIC flag and
cannot access the page allocator atomic reserves.  This patch addresses
the problem.

The user-visible impact depends on the workload but potentially atomic
allocations unnecessarily fail without this path.

Link: http://lkml.kernel.org/r/20160610093832.GK2527@techsingularity.netSigned-off-by: NMel Gorman <mgorman@techsingularity.net>
Reported-by: NMarcin Wojtas <mw@semihalf.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>	[4.4+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently we may put reserved by mempool elements into quarantine via
kasan_kfree().  This is totally wrong since quarantine may really free
these objects.  So when mempool will try to use such element,
use-after-free will happen.  Or mempool may decide that it no longer
need that element and double-free it.

So don't put object into quarantine in kasan_kfree(), just poison it.
Rename kasan_kfree() to kasan_poison_kfree() to respect that.

Also, we shouldn't use kasan_slab_alloc()/kasan_krealloc() in
kasan_unpoison_element() because those functions may update allocation
stacktrace.  This would be wrong for the most of the remove_element call
sites.

(The only call site where we may want to update alloc stacktrace is
 in mempool_alloc(). Kmemleak solves this by calling
 kmemleak_update_trace(), so we could make something like that too.
 But this is out of scope of this patch).

Fixes: 55834c59 ("mm: kasan: initial memory quarantine implementation")
Link: http://lkml.kernel.org/r/575977C3.1010905@virtuozzo.comSigned-off-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: NKuthonuzo Luruo <kuthonuzo.luruo@hpe.com>
Acked-by: NAlexander Potapenko <glider@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Kostya Serebryany <kcc@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When fallocate is interrupted it will undo a range that extends one byte
past its range of allocated pages.  This can corrupt an in-use page by
zeroing out its first byte.  Instead, undo using the inclusive byte
range.

Fixes: 1635f6a7 ("tmpfs: undo fallocation on failure")
Link: http://lkml.kernel.org/r/1462713387-16724-1-git-send-email-anthony.romano@coreos.comSigned-off-by: NAnthony Romano <anthony.romano@coreos.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Brandon Philips <brandon@ifup.co>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Since commit 36324a99 ("oom: clear TIF_MEMDIE after oom_reaper
managed to unmap the address space") changed to use find_lock_task_mm()
for finding a mm_struct to reap, it is guaranteed that mm->mm_users > 0
because find_lock_task_mm() returns a task_struct with ->mm != NULL.
Therefore, we can safely use atomic_inc().

Link: http://lkml.kernel.org/r/1465024759-8074-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jpSigned-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit e2fe1456 ("oom_reaper: close race with exiting task") reduced
frequency of needlessly selecting next OOM victim, but was calling
mmput_async() when atomic_inc_not_zero() failed.

Link: http://lkml.kernel.org/r/1464423365-5555-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jpSigned-off-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Export these symbols such that UBIFS can implement
->migratepage.

Cc: stable@vger.kernel.org
Signed-off-by: NRichard Weinberger <richard@nod.at>
Acked-by: NChristoph Hellwig <hch@lst.de>

I noticed that the logic in the fadvise64_64 syscall is incorrect for
partial pages.  While first page of the region is correctly skipped if
it is partial, the last page of the region is mistakenly discarded.
This leads to problems for applications that read data in
non-page-aligned chunks discarding already processed data between the
reads.

A somewhat misguided application that does something like write(XX bytes
(non-page-alligned)); drop the data it just wrote; repeat gets a
significant penalty in performance as a result.

Link: http://lkml.kernel.org/r/1464917140-1506698-1-git-send-email-green@linuxhacker.ruSigned-off-by: NOleg Drokin <green@linuxhacker.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch is based on https://patchwork.ozlabs.org/patch/574623/.

Tejun submitted commit 23d11a58 ("workqueue: skip flush dependency
checks for legacy workqueues") for the legacy create*_workqueue()
interface.

But some workq created by alloc_workqueue still reports warning on
memory reclaim, e.g nvme_workq with flag WQ_MEM_RECLAIM set:

    workqueue: WQ_MEM_RECLAIM nvme:nvme_reset_work is flushing !WQ_MEM_RECLAIM events:lru_add_drain_per_cpu
    ------------[ cut here ]------------
    WARNING: CPU: 0 PID: 6 at SoC/linux/kernel/workqueue.c:2448 check_flush_dependency+0xb4/0x10c
    ...
    check_flush_dependency+0xb4/0x10c
    flush_work+0x54/0x140
    lru_add_drain_all+0x138/0x188
    migrate_prep+0xc/0x18
    alloc_contig_range+0xf4/0x350
    cma_alloc+0xec/0x1e4
    dma_alloc_from_contiguous+0x38/0x40
    __dma_alloc+0x74/0x25c
    nvme_alloc_queue+0xcc/0x36c
    nvme_reset_work+0x5c4/0xda8
    process_one_work+0x128/0x2ec
    worker_thread+0x58/0x434
    kthread+0xd4/0xe8
    ret_from_fork+0x10/0x50

That's because lru_add_drain_all() will schedule the drain work on
system_wq, whose flag is set to 0, !WQ_MEM_RECLAIM.

Introduce a dedicated WQ_MEM_RECLAIM workqueue to do
lru_add_drain_all(), aiding in getting memory freed.

Link: http://lkml.kernel.org/r/1464917521-9775-1-git-send-email-shhuiw@foxmail.comSigned-off-by: NWang Sheng-Hui <shhuiw@foxmail.com>
Acked-by: NTejun Heo <tj@kernel.org>
Cc: Keith Busch <keith.busch@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thierry Reding <treding@nvidia.com>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Christian Borntraeger reported a kernel panic after corrupt page counts,
and it turned out to be a regression introduced with commit aa88b68c
("thp: keep huge zero page pinned until tlb flush"), at least on s390.

put_huge_zero_page() was moved over from zap_huge_pmd() to
release_pages(), and it was replaced by tlb_remove_page().  However,
release_pages() might not always be triggered by (the arch-specific)
tlb_remove_page().

On s390 we call free_page_and_swap_cache() from tlb_remove_page(), and
not tlb_flush_mmu() -> free_pages_and_swap_cache() like the generic
version, because we don't use the MMU-gather logic.  Although both
functions have very similar names, they are doing very unsimilar things,
in particular free_page_xxx is just doing a put_page(), while
free_pages_xxx calls release_pages().

This of course results in very harmful put_page()s on the huge zero
page, on architectures where tlb_remove_page() is implemented in this
way.  It seems to affect only s390 and sh, but sh doesn't have THP
support, so the problem (currently) probably only exists on s390.

The following quick hack fixed the issue:

Link: http://lkml.kernel.org/r/20160602172141.75c006a9@thinkpadSigned-off-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Reported-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Tested-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: <stable@vger.kernel.org>	[4.6.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Revert commit 1383399d ("mm: memcontrol: fix possible css ref leak
on oom").  Johannes points out "There is a task_in_memcg_oom() check
before calling mem_cgroup_oom()".
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Change the following memory hot-add error messages to info messages.
There is no need for these to be errors.

   kasan: WARNING: KASAN doesn't support memory hot-add
   kasan: Memory hot-add will be disabled

Link: http://lkml.kernel.org/r/1464794430-5486-1-git-send-email-shuahkh@osg.samsung.comSigned-off-by: NShuah Khan <shuahkh@osg.samsung.com>
Acked-by: NAndrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When creating a private mapping of a hugetlbfs file, it is possible to
unmap pages via ftruncate or fallocate hole punch.  If subsequent faults
repopulate these mappings, the reserve counts will go negative.  This is
because the code currently assumes all faults to private mappings will
consume reserves.  The problem can be recreated as follows:

 - mmap(MAP_PRIVATE) a file in hugetlbfs filesystem
 - write fault in pages in the mapping
 - fallocate(FALLOC_FL_PUNCH_HOLE) some pages in the mapping
 - write fault in pages in the hole

This will result in negative huge page reserve counts and negative
subpool usage counts for the hugetlbfs.  Note that this can also be
recreated with ftruncate, but fallocate is more straight forward.

This patch modifies the routines vma_needs_reserves and vma_has_reserves
to examine the reserve map associated with private mappings similar to
that for shared mappings.  However, the reserve map semantics for
private and shared mappings are very different.  This results in subtly
different code that is explained in the comments.

Link: http://lkml.kernel.org/r/1464720957-15698-1-git-send-email-mike.kravetz@oracle.comSigned-off-by: NMike Kravetz <mike.kravetz@oracle.com>
Acked-by: NHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The optimistic fast path may use cpuset_current_mems_allowed instead of
of a NULL nodemask supplied by the caller for cpuset allocations.  The
preferred zone is calculated on this basis for statistic purposes and as
a starting point in the zonelist iterator.

However, if the context can ignore memory policies due to being atomic
or being able to ignore watermarks then the starting point in the
zonelist iterator is no longer correct.  This patch resets the zonelist
iterator in the allocator slowpath if the context can ignore memory
policies.  This will alter the zone used for statistics but only after
it is known that it makes sense for that context.  Resetting it before
entering the slowpath would potentially allow an ALLOC_CPUSET allocation
to be accounted for against the wrong zone.  Note that while nodemask is
not explicitly set to the original nodemask, it would only have been
overwritten if cpuset_enabled() and it was reset before the slowpath was
entered.

Link: http://lkml.kernel.org/r/20160602103936.GU2527@techsingularity.net
Fixes: c33d6c06 ("mm, page_alloc: avoid looking up the first zone in a zonelist twice")
Signed-off-by: NMel Gorman <mgorman@techsingularity.net>
Reported-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Tested-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Geert Uytterhoeven reported the following problem that bisected to
commit c33d6c06 ("mm, page_alloc: avoid looking up the first zone
in a zonelist twice") on m68k/ARAnyM

    BUG: scheduling while atomic: cron/668/0x10c9a0c0
    Modules linked in:
    CPU: 0 PID: 668 Comm: cron Not tainted 4.6.0-atari-05133-gc33d6c06 #364
    Call Trace: [<0003d7d0>] __schedule_bug+0x40/0x54
      __schedule+0x312/0x388
      __schedule+0x0/0x388
      prepare_to_wait+0x0/0x52
      schedule+0x64/0x82
      schedule_timeout+0xda/0x104
      set_next_entity+0x18/0x40
      pick_next_task_fair+0x78/0xda
      io_schedule_timeout+0x36/0x4a
      bit_wait_io+0x0/0x40
      bit_wait_io+0x12/0x40
      __wait_on_bit+0x46/0x76
      wait_on_page_bit_killable+0x64/0x6c
      bit_wait_io+0x0/0x40
      wake_bit_function+0x0/0x4e
      __lock_page_or_retry+0xde/0x124
      do_scan_async+0x114/0x17c
      lookup_swap_cache+0x24/0x4e
      handle_mm_fault+0x626/0x7de
      find_vma+0x0/0x66
      down_read+0x0/0xe
      wait_on_page_bit_killable_timeout+0x77/0x7c
      find_vma+0x16/0x66
      do_page_fault+0xe6/0x23a
      res_func+0xa3c/0x141a
      buserr_c+0x190/0x6d4
      res_func+0xa3c/0x141a
      buserr+0x20/0x28
      res_func+0xa3c/0x141a
      buserr+0x20/0x28

The relationship is not obvious but it's due to a failure to rescan the
full zonelist after the fair zone allocation policy exhausts the batch
count.  While this is a functional problem, it's also a performance
issue.  A page allocator microbenchmark showed the following

                                   4.7.0-rc1                  4.7.0-rc1
                                     vanilla                 reset-v1r2
  Min      alloc-odr0-1     327.00 (  0.00%)           326.00 (  0.31%)
  Min      alloc-odr0-2     235.00 (  0.00%)           235.00 (  0.00%)
  Min      alloc-odr0-4     198.00 (  0.00%)           198.00 (  0.00%)
  Min      alloc-odr0-8     170.00 (  0.00%)           170.00 (  0.00%)
  Min      alloc-odr0-16    156.00 (  0.00%)           156.00 (  0.00%)
  Min      alloc-odr0-32    150.00 (  0.00%)           150.00 (  0.00%)
  Min      alloc-odr0-64    146.00 (  0.00%)           146.00 (  0.00%)
  Min      alloc-odr0-128   145.00 (  0.00%)           145.00 (  0.00%)
  Min      alloc-odr0-256   155.00 (  0.00%)           155.00 (  0.00%)
  Min      alloc-odr0-512   168.00 (  0.00%)           165.00 (  1.79%)
  Min      alloc-odr0-1024  175.00 (  0.00%)           174.00 (  0.57%)
  Min      alloc-odr0-2048  180.00 (  0.00%)           180.00 (  0.00%)
  Min      alloc-odr0-4096  187.00 (  0.00%)           186.00 (  0.53%)
  Min      alloc-odr0-8192  190.00 (  0.00%)           190.00 (  0.00%)
  Min      alloc-odr0-16384 191.00 (  0.00%)           191.00 (  0.00%)
  Min      alloc-odr1-1     736.00 (  0.00%)           445.00 ( 39.54%)
  Min      alloc-odr1-2     343.00 (  0.00%)           335.00 (  2.33%)
  Min      alloc-odr1-4     277.00 (  0.00%)           270.00 (  2.53%)
  Min      alloc-odr1-8     238.00 (  0.00%)           233.00 (  2.10%)
  Min      alloc-odr1-16    224.00 (  0.00%)           218.00 (  2.68%)
  Min      alloc-odr1-32    210.00 (  0.00%)           208.00 (  0.95%)
  Min      alloc-odr1-64    207.00 (  0.00%)           203.00 (  1.93%)
  Min      alloc-odr1-128   276.00 (  0.00%)           202.00 ( 26.81%)
  Min      alloc-odr1-256   206.00 (  0.00%)           202.00 (  1.94%)
  Min      alloc-odr1-512   207.00 (  0.00%)           202.00 (  2.42%)
  Min      alloc-odr1-1024  208.00 (  0.00%)           205.00 (  1.44%)
  Min      alloc-odr1-2048  213.00 (  0.00%)           212.00 (  0.47%)
  Min      alloc-odr1-4096  218.00 (  0.00%)           216.00 (  0.92%)
  Min      alloc-odr1-8192  341.00 (  0.00%)           219.00 ( 35.78%)

Note that order-0 allocations are unaffected but higher orders get a
small boost from this patch and a large reduction in system CPU usage
overall as can be seen here:

             4.7.0-rc1   4.7.0-rc1
               vanilla  reset-v1r2
  User           85.32       86.31
  System       2221.39     2053.36
  Elapsed      2368.89     2202.47

Fixes: c33d6c06 ("mm, page_alloc: avoid looking up the first zone in a zonelist twice")
Link: http://lkml.kernel.org/r/20160531100848.GR2527@techsingularity.netSigned-off-by: NMel Gorman <mgorman@techsingularity.net>
Reported-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Tested-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Tested-by: NMikulas Patocka <mpatocka@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Oleg has noted that siglock usage in try_oom_reaper is both pointless
and dangerous.  signal_group_exit can be checked lockless.  The problem
is that sighand becomes NULL in __exit_signal so we can crash.

Fixes: 3ef22dff ("oom, oom_reaper: try to reap tasks which skip regular OOM killer path")
Link: http://lkml.kernel.org/r/1464679423-30218-1-git-send-email-mhocko@kernel.orgSigned-off-by: NMichal Hocko <mhocko@suse.com>
Suggested-by: NOleg Nesterov <oleg@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In DEBUG_VM kernel, we can hit infinite loop for order == 0 in
buffered_rmqueue() when check_new_pcp() returns 1, because the bad page
is never removed from the pcp list.  Fix this by removing the page
before retrying.  Also we don't need to check if page is non-NULL,
because we simply grab it from the list which was just tested for being
non-empty.

Fixes: 479f854a ("mm, page_alloc: defer debugging checks of pages allocated from the PCP")
Link: http://lkml.kernel.org/r/20160530090154.GM2527@techsingularity.netSigned-off-by: NVlastimil Babka <vbabka@suse.cz>
Signed-off-by: NMel Gorman <mgorman@techsingularity.net>
Reported-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix erroneous z3fold header access in a HEADLESS page in reclaim
function, and change one remaining direct handle-to-buddy conversion to
use the appropriate helper.

Link: http://lkml.kernel.org/r/5748706F.9020208@gmail.comSigned-off-by: NVitaly Wool <vitalywool@gmail.com>
Reviewed-by: NDan Streetman <ddstreet@ieee.org>
Cc: Seth Jennings <sjenning@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

memcg_offline_kmem() may be called from memcg_free_kmem() after a css
init failure.  memcg_free_kmem() is a ->css_free callback which is
called without cgroup_mutex and memcg_offline_kmem() ends up using
css_for_each_descendant_pre() without any locking.  Fix it by adding rcu
read locking around it.

    mkdir: cannot create directory `65530': No space left on device
    ===============================
    [ INFO: suspicious RCU usage. ]
    4.6.0-work+ #321 Not tainted
    -------------------------------
    kernel/cgroup.c:4008 cgroup_mutex or RCU read lock required!
     [  527.243970] other info that might help us debug this:
     [  527.244715]
    rcu_scheduler_active = 1, debug_locks = 0
    2 locks held by kworker/0:5/1664:
     #0:  ("cgroup_destroy"){.+.+..}, at: [<ffffffff81060ab5>] process_one_work+0x165/0x4a0
     #1:  ((&css->destroy_work)#3){+.+...}, at: [<ffffffff81060ab5>] process_one_work+0x165/0x4a0
     [  527.248098] stack backtrace:
    CPU: 0 PID: 1664 Comm: kworker/0:5 Not tainted 4.6.0-work+ #321
    Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.1-1.fc24 04/01/2014
    Workqueue: cgroup_destroy css_free_work_fn
    Call Trace:
      dump_stack+0x68/0xa1
      lockdep_rcu_suspicious+0xd7/0x110
      css_next_descendant_pre+0x7d/0xb0
      memcg_offline_kmem.part.44+0x4a/0xc0
      mem_cgroup_css_free+0x1ec/0x200
      css_free_work_fn+0x49/0x5e0
      process_one_work+0x1c5/0x4a0
      worker_thread+0x49/0x490
      kthread+0xea/0x100
      ret_from_fork+0x1f/0x40

Link: http://lkml.kernel.org/r/20160526203018.GG23194@mtj.duckdns.orgSigned-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NVladimir Davydov <vdavydov@virtuozzo.com>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: <stable@vger.kernel.org>	[4.5+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Per the discussion with Joonsoo Kim [1], we need check the return value
of lookup_page_ext() for all call sites since it might return NULL in
some cases, although it is unlikely, i.e.  memory hotplug.

Tested with ltp with "page_owner=0".

[1] http://lkml.kernel.org/r/20160519002809.GA10245@js1304-P5Q-DELUXE

[akpm@linux-foundation.org: fix build-breaking typos]
[arnd@arndb.de: fix build problems from lookup_page_ext]
  Link: http://lkml.kernel.org/r/6285269.2CksypHdYp@wuerfel
[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/1464023768-31025-1-git-send-email-yang.shi@linaro.orgSigned-off-by: NYang Shi <yang.shi@linaro.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When remapping pages accounting for 4G or more memory space, the
operation 'count << PAGE_SHIFT' overflows as it is performed on an
integer.  Solution: cast before doing the bitshift.

[akpm@linux-foundation.org: fix vm_unmap_ram() also]
[akpm@linux-foundation.org: fix vmap() as well, per Guillermo]
Link: http://lkml.kernel.org/r/etPan.57175fb3.7a271c6b.2bd@naudit.esSigned-off-by: NGuillermo Julián Moreno <guillermo.julian@naudit.es>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>