linux-stable.git/mm, branch v3.16.35

mm: fix invalid node in alloc_migrate_target()

2016-04-30T22:06:08+00:00

commit 6f25a14a7053b69917e2ebea0d31dd444cd31fd5 upstream.

It is incorrect to use next_node to find a target node, it will return
MAX_NUMNODES or invalid node.  This will lead to crash in buddy system
allocation.

Fixes: c8721bbbdd36 ("mm: memory-hotplug: enable memory hotplug to handle hugepage")
Signed-off-by: Xishi Qiu 
Acked-by: Vlastimil Babka 
Acked-by: Naoya Horiguchi 
Cc: Joonsoo Kim 
Cc: David Rientjes 
Cc: "Laura Abbott" 
Cc: Hui Zhu 
Cc: Wang Xiaoqiang 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Ben Hutchings

mm: replace vma_lock_anon_vma with anon_vma_lock_read/write

2016-02-25T10:34:44+00:00

commit 12352d3cae2cebe18805a91fab34b534d7444231 upstream.

Sequence vma_lock_anon_vma() - vma_unlock_anon_vma() isn't safe if
anon_vma appeared between lock and unlock.  We have to check anon_vma
first or call anon_vma_prepare() to be sure that it's here.  There are
only few users of these legacy helpers.  Let's get rid of them.

This patch fixes anon_vma lock imbalance in validate_mm().  Write lock
isn't required here, read lock is enough.

And reorders expand_downwards/expand_upwards: security_mmap_addr() and
wrapping-around check don't have to be under anon vma lock.

Link: https://lkml.kernel.org/r/CACT4Y+Y908EjM2z=706dv4rV6dWtxTLK9nFg9_7DhRMLppBo2g@mail.gmail.com
Signed-off-by: Konstantin Khlebnikov 
Reported-by: Dmitry Vyukov 
Acked-by: Kirill A. Shutemov 
Cc: Andrea Arcangeli 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques

mm, vmstat: fix wrong WQ sleep when memory reclaim doesn't make any progress

2016-02-25T10:34:43+00:00

commit 564e81a57f9788b1475127012e0fd44e9049e342 upstream.

Jan Stancek has reported that system occasionally hanging after "oom01"
testcase from LTP triggers OOM.  Guessing from a result that there is a
kworker thread doing memory allocation and the values between "Node 0
Normal free:" and "Node 0 Normal:" differs when hanging, vmstat is not
up-to-date for some reason.

According to commit 373ccbe59270 ("mm, vmstat: allow WQ concurrency to
discover memory reclaim doesn't make any progress"), it meant to force
the kworker thread to take a short sleep, but it by error used
schedule_timeout(1).  We missed that schedule_timeout() in state
TASK_RUNNING doesn't do anything.

Fix it by using schedule_timeout_uninterruptible(1) which forces the
kworker thread to take a short sleep in order to make sure that vmstat
is up-to-date.

Fixes: 373ccbe59270 ("mm, vmstat: allow WQ concurrency to discover memory reclaim doesn't make any progress")
Signed-off-by: Tetsuo Handa 
Reported-by: Jan Stancek 
Acked-by: Michal Hocko 
Cc: Tejun Heo 
Cc: Cristopher Lameter 
Cc: Joonsoo Kim 
Cc: Arkadiusz Miskiewicz 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Luis Henriques

vmstat: explicitly schedule per-cpu work on the CPU we need it to run on

2016-02-24T10:26:37+00:00

commit 176bed1de5bf977938cad26551969eca8f0883b1 upstream.

The vmstat code uses "schedule_delayed_work_on()" to do the initial
startup of the delayed work on the right CPU, but then once it was
started it would use the non-cpu-specific "schedule_delayed_work()" to
re-schedule it on that CPU.

That just happened to schedule it on the same CPU historically (well, in
almost all situations), but the code _requires_ this work to be per-cpu,
and should say so explicitly rather than depend on the non-cpu-specific
scheduling to schedule on the current CPU.

The timer code is being changed to not be as single-minded in always
running things on the calling CPU.

See also commit 874bbfe600a6 ("workqueue: make sure delayed work run in
local cpu") that for now maintains the local CPU guarantees just in case
there are other broken users that depended on the accidental behavior.

js: 3.12 backport

Cc: Christoph Lameter 
Cc: Tejun Heo 
Cc: Mike Galbraith 
Cc: Michal Hocko 
Signed-off-by: Linus Torvalds 
Signed-off-by: Jiri Slaby 
[ kamal: backport to 3.16-stable: use queue_delayed_work_on() ]
Signed-off-by: Kamal Mostafa 
Signed-off-by: Luis Henriques

memcg: only free spare array when readers are done

2016-02-02T19:09:49+00:00

commit 6611d8d76132f86faa501de9451a89bf23fb2371 upstream.

A spare array holding mem cgroup threshold events is kept around to make
sure we can always safely deregister an event and have an array to store
the new set of events in.

In the scenario where we're going from 1 to 0 registered events, the
pointer to the primary array containing 1 event is copied to the spare
slot, and then the spare slot is freed because no events are left.
However, it is freed before calling synchronize_rcu(), which means
readers may still be accessing threshold->primary after it is freed.

Fixed by only freeing after synchronize_rcu().

Signed-off-by: Martijn Coenen 
Cc: Johannes Weiner 
Acked-by: Michal Hocko 
Cc: Vladimir Davydov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Luis Henriques

mm: soft-offline: check return value in second __get_any_page() call

2016-02-02T19:09:48+00:00

commit d96b339f453997f2f08c52da3f41423be48c978f upstream.

I saw the following BUG_ON triggered in a testcase where a process calls
madvise(MADV_SOFT_OFFLINE) on thps, along with a background process that
calls migratepages command repeatedly (doing ping-pong among different
NUMA nodes) for the first process:

   Soft offlining page 0x60000 at 0x700000600000
   __get_any_page: 0x60000 free buddy page
   page:ffffea0001800000 count:0 mapcount:-127 mapping:          (null) index:0x1
   flags: 0x1fffc0000000000()
   page dumped because: VM_BUG_ON_PAGE(atomic_read(&page->_count) == 0)
   ------------[ cut here ]------------
   kernel BUG at /src/linux-dev/include/linux/mm.h:342!
   invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC
   Modules linked in: cfg80211 rfkill crc32c_intel serio_raw virtio_balloon i2c_piix4 virtio_blk virtio_net ata_generic pata_acpi
   CPU: 3 PID: 3035 Comm: test_alloc_gene Tainted: G           O    4.4.0-rc8-v4.4-rc8-160107-1501-00000-rc8+ #74
   Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
   task: ffff88007c63d5c0 ti: ffff88007c210000 task.ti: ffff88007c210000
   RIP: 0010:[]  [] put_page+0x5c/0x60
   RSP: 0018:ffff88007c213e00  EFLAGS: 00010246
   Call Trace:
     put_hwpoison_page+0x4e/0x80
     soft_offline_page+0x501/0x520
     SyS_madvise+0x6bc/0x6f0
     entry_SYSCALL_64_fastpath+0x12/0x6a
   Code: 8b fc ff ff 5b 5d c3 48 89 df e8 b0 fa ff ff 48 89 df 31 f6 e8 c6 7d ff ff 5b 5d c3 48 c7 c6 08 54 a2 81 48 89 df e8 a4 c5 01 00 <0f> 0b 66 90 66 66 66 66 90 55 48 89 e5 41 55 41 54 53 48 8b 47
   RIP  [] put_page+0x5c/0x60
    RSP 

The root cause resides in get_any_page() which retries to get a refcount
of the page to be soft-offlined.  This function calls
put_hwpoison_page(), expecting that the target page is putback to LRU
list.  But it can be also freed to buddy.  So the second check need to
care about such case.

Fixes: af8fae7c0886 ("mm/memory-failure.c: clean up soft_offline_page()")
Signed-off-by: Naoya Horiguchi 
Cc: Sasha Levin 
Cc: Aneesh Kumar K.V 
Cc: Vlastimil Babka 
Cc: Jerome Marchand 
Cc: Andrea Arcangeli 
Cc: Hugh Dickins 
Cc: Dave Hansen 
Cc: Mel Gorman 
Cc: Rik van Riel 
Cc: Steve Capper 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Christoph Lameter 
Cc: David Rientjes 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Luis Henriques

virtio_balloon: fix race between migration and ballooning

2016-02-02T19:09:33+00:00

commit 21ea9fb69e7c4b1b1559c3e410943d3ff248ffcb upstream.

In balloon_page_dequeue, pages_lock should cover the loop
(ie, list_for_each_entry_safe). Otherwise, the cursor page could
be isolated by compaction and then list_del by isolation could
poison the page->lru.{prev,next} so the loop finally could
access wrong address like this. This patch fixes the bug.

general protection fault: 0000 [#1] SMP
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 2 PID: 82 Comm: vballoon Not tainted 4.4.0-rc5-mm1-access_bit+ #1906
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff8800a7ff0000 ti: ffff8800a7fec000 task.ti: ffff8800a7fec000
RIP: 0010:[]  [] balloon_page_dequeue+0x54/0x130
RSP: 0018:ffff8800a7fefdc0  EFLAGS: 00010246
RAX: ffff88013fff9a70 RBX: ffffea000056fe00 RCX: 0000000000002b7d
RDX: ffff88013fff9a70 RSI: ffffea000056fe00 RDI: ffff88013fff9a68
RBP: ffff8800a7fefde8 R08: ffffea000056fda0 R09: 0000000000000000
R10: ffff8800a7fefd90 R11: 0000000000000001 R12: dead0000000000e0
R13: ffffea000056fe20 R14: ffff880138809070 R15: ffff880138809060
FS:  0000000000000000(0000) GS:ffff88013fc40000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 00007f229c10e000 CR3: 00000000b8b53000 CR4: 00000000000006a0
Stack:
 0000000000000100 ffff880138809088 ffff880138809000 ffff880138809060
 0000000000000046 ffff8800a7fefe28 ffffffff812c86d3 ffff880138809020
 ffff880138809000 fffffffffff91900 0000000000000100 ffff880138809060
Call Trace:
 [] leak_balloon+0x93/0x1a0
 [] balloon+0x217/0x2a0
 [] ? __schedule+0x31e/0x8b0
 [] ? abort_exclusive_wait+0xb0/0xb0
 [] ? update_balloon_stats+0xf0/0xf0
 [] kthread+0xc9/0xe0
 [] ? kthread_park+0x60/0x60
 [] ret_from_fork+0x3f/0x70
 [] ? kthread_park+0x60/0x60
Code: 8d 60 e0 0f 84 af 00 00 00 48 8b 43 20 a8 01 75 3b 48 89 d8 f0 0f ba 28 00 72 10 48 8b 03 f6 c4 08 75 2f 48 89 df e8 8c 83 f9 ff <49> 8b 44 24 20 4d 8d 6c 24 20 48 83 e8 20 4d 39 f5 74 7a 4c 89
RIP  [] balloon_page_dequeue+0x54/0x130
 RSP 
---[ end trace 43cf28060d708d5f ]---
Kernel panic - not syncing: Fatal exception
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled

Signed-off-by: Minchan Kim 
Signed-off-by: Michael S. Tsirkin 
Acked-by: Rafael Aquini 
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques

mm/memory_hotplug.c: check for missing sections in test_pages_in_a_zone()

2016-01-25T10:43:59+00:00

commit 5f0f2887f4de9508dcf438deab28f1de8070c271 upstream.

test_pages_in_a_zone() does not account for the possibility of missing
sections in the given pfn range.  pfn_valid_within always returns 1 when
CONFIG_HOLES_IN_ZONE is not set, allowing invalid pfns from missing
sections to pass the test, leading to a kernel oops.

Wrap an additional pfn loop with PAGES_PER_SECTION granularity to check
for missing sections before proceeding into the zone-check code.

This also prevents a crash from offlining memory devices with missing
sections.  Despite this, it may be a good idea to keep the related patch
'[PATCH 3/3] drivers: memory: prohibit offlining of memory blocks with
missing sections' because missing sections in a memory block may lead to
other problems not covered by the scope of this fix.

Signed-off-by: Andrew Banman 
Acked-by: Alex Thorlton 
Cc: Russ Anderson 
Cc: Alex Thorlton 
Cc: Yinghai Lu 
Cc: Greg KH 
Cc: Seth Jennings 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Luis Henriques

vmstat: allocate vmstat_wq before it is used

2016-01-25T10:43:53+00:00

commit 751e5f5c753e8d447bcf89f9e96b9616ac081628 upstream.

kernel test robot has reported the following crash:

  BUG: unable to handle kernel NULL pointer dereference at 00000100
  IP: [] __queue_work+0x26/0x390
  *pdpt = 0000000000000000 *pde = f000ff53f000ff53 *pde = f000ff53f000ff53
  Oops: 0000 [#1] PREEMPT PREEMPT SMP SMP
  CPU: 0 PID: 24 Comm: kworker/0:1 Not tainted 4.4.0-rc4-00139-g373ccbe #1
  Workqueue: events vmstat_shepherd
  task: cb684600 ti: cb7ba000 task.ti: cb7ba000
  EIP: 0060:[] EFLAGS: 00010046 CPU: 0
  EIP is at __queue_work+0x26/0x390
  EAX: 00000046 EBX: cbb37800 ECX: cbb37800 EDX: 00000000
  ESI: 00000000 EDI: 00000000 EBP: cb7bbe68 ESP: cb7bbe38
   DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
  CR0: 8005003b CR2: 00000100 CR3: 01fd5000 CR4: 000006b0
  Stack:
  Call Trace:
    __queue_delayed_work+0xa1/0x160
    queue_delayed_work_on+0x36/0x60
    vmstat_shepherd+0xad/0xf0
    process_one_work+0x1aa/0x4c0
    worker_thread+0x41/0x440
    kthread+0xb0/0xd0
    ret_from_kernel_thread+0x21/0x40

The reason is that start_shepherd_timer schedules the shepherd work item
which uses vmstat_wq (vmstat_shepherd) before setup_vmstat allocates
that workqueue so if the further initialization takes more than HZ we
might end up scheduling on a NULL vmstat_wq.  This is really unlikely
but not impossible.

Fixes: 373ccbe59270 ("mm, vmstat: allow WQ concurrency to discover memory reclaim doesn't make any progress")
Reported-by: kernel test robot 
Signed-off-by: Michal Hocko 
Tested-by: Tetsuo Handa 
Cc: Andrew Morton 
Signed-off-by: Linus Torvalds 
Cc: Ben Hutchings 
[ luis: backported to 3.16: based on Ben's backport to 3.2:
  - as with 3.2, there's a similar race but with the CPU hotplug code ]
Signed-off-by: Luis Henriques

mm: hugetlb: call huge_pte_alloc() only if ptep is null

2016-01-25T10:43:28+00:00

commit 0d777df5d8953293be090d9ab5a355db893e8357 upstream.

Currently at the beginning of hugetlb_fault(), we call huge_pte_offset()
and check whether the obtained *ptep is a migration/hwpoison entry or
not.  And if not, then we get to call huge_pte_alloc().  This is racy
because the *ptep could turn into migration/hwpoison entry after the
huge_pte_offset() check.  This race results in BUG_ON in
huge_pte_alloc().

We don't have to call huge_pte_alloc() when the huge_pte_offset()
returns non-NULL, so let's fix this bug with moving the code into else
block.

Note that the *ptep could turn into a migration/hwpoison entry after
this block, but that's not a problem because we have another
!pte_present check later (we never go into hugetlb_no_page() in that
case.)

Fixes: 290408d4a250 ("hugetlb: hugepage migration core")
Signed-off-by: Naoya Horiguchi 
Acked-by: Hillf Danton 
Acked-by: David Rientjes 
Cc: Hugh Dickins 
Cc: Dave Hansen 
Cc: Mel Gorman 
Cc: Joonsoo Kim 
Cc: Mike Kravetz 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Luis Henriques