ioctx_add_table() is the writer, it does not need rcu_read_lock() to
protect ->ioctx_table. It relies on mm->ioctx_lock and rcu locks just
add the confusion.

And it doesn't need rcu_dereference() by the same reason, it must see
any updates previously done under the same ->ioctx_lock. We could use
rcu_dereference_protected() but the patch uses rcu_dereference_raw(),
the function is simple enough.

The same for kill_ioctx(), although it does not update the pointer.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>

On 04/30, Benjamin LaHaise wrote:
>
> > -		ctx->mmap_size = 0;
> > -
> > -		kill_ioctx(mm, ctx, NULL);
> > +		if (ctx) {
> > +			ctx->mmap_size = 0;
> > +			kill_ioctx(mm, ctx, NULL);
> > +		}
>
> Rather than indenting and moving the two lines changing mmap_size and the
> kill_ioctx() call, why not just do "if (!ctx) ... continue;"?  That reduces
> the number of lines changed and avoid excessive indentation.

OK. To me the code looks better/simpler with "if (ctx)", but this is subjective
of course, I won't argue.

The patch still removes the empty line between mmap_size = 0 and kill_ioctx(),
we reset mmap_size only for kill_ioctx(). But feel free to remove this change.

-------------------------------------------------------------------------------
Subject: [PATCH v3 1/2] aio: change exit_aio() to load mm->ioctx_table once and avoid rcu_read_lock()

1. We can read ->ioctx_table only once and we do not read rcu_read_lock()
   or even rcu_dereference().

   This mm has no users, nobody else can play with ->ioctx_table. Otherwise
   the code is buggy anyway, if we need rcu_read_lock() in a loop because
   ->ioctx_table can be updated then kfree(table) is obviously wrong.

2. Update the comment. "exit_mmap(mm) is coming" is the good reason to avoid
   munmap(), but another reason is that we simply can't do vm_munmap() unless
   current->mm == mm and this is not true in general, the caller is mmput().

3. We do not really need to nullify mm->ioctx_table before return, probably
   the current code does this to catch the potential problems. But in this
   case RCU_INIT_POINTER(NULL) looks better.
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>

A kernel memory disclosure was introduced in aio_read_events_ring() in v3.10
by commit a31ad380.  The changes made to
aio_read_events_ring() failed to correctly limit the index into
ctx->ring_pages[], allowing an attacked to cause the subsequent kmap() of
an arbitrary page with a copy_to_user() to copy the contents into userspace.
This vulnerability has been assigned CVE-2014-0206.  Thanks to Mateusz and
Petr for disclosing this issue.

This patch applies to v3.12+.  A separate backport is needed for 3.10/3.11.
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Petr Matousek <pmatouse@redhat.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: stable@vger.kernel.org

The aio cleanups and optimizations by kmo that were merged into the 3.10
tree added a regression for userspace event reaping.  Specifically, the
reference counts are not decremented if the event is reaped in userspace,
leading to the application being unable to submit further aio requests.
This patch applies to 3.12+.  A separate backport is required for 3.10/3.11.
This issue was uncovered as part of CVE-2014-0206.
Signed-off-by: NBenjamin LaHaise <bcrl@kvack.org>
Cc: stable@vger.kernel.org
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Petr Matousek <pmatouse@redhat.com>

Pull compress bugfixes from Greg KH:
 "Here are two bugfixes for some compression functions that resolve some
  errors when uncompressing some pathalogical data.  Both were found by
  Don A  Bailey"

* tag 'compress-3.16-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  lz4: ensure length does not wrap
  lzo: properly check for overruns

Merge fixes from Andrew Morton:
 "The nmi patch and watchdog patch aren't actually fixes - they're
  features which needed a few last-minutes touchups.

  Otherwise, a rather large batch of fixes - ocfs2 review takes a while
  and I got distracted and missed last week's batch"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (31 commits)
  ocfs2/dlm: do not purge lockres that is queued for assert master
  ocfs2: do not return DLM_MIGRATE_RESPONSE_MASTERY_REF to avoid endless,loop during umount
  ocfs2: manually do the iput once ocfs2_add_entry failed in ocfs2_symlink and ocfs2_mknod
  ocfs2: fix a tiny race when running dirop_fileop_racer
  ocfs2/dlm: fix misuse of list_move_tail() in dlm_run_purge_list()
  ocfs2: refcount: take rw_lock in ocfs2_reflink
  ocfs2: revert "ocfs2: fix NULL pointer dereference when dismount and ocfs2rec simultaneously"
  ocfs2: fix deadlock when two nodes are converting same lock from PR to EX and idletimeout closes conn
  ocfs2: should add inode into orphan dir after updating entry in ocfs2_rename()
  mm: fix crashes from mbind() merging vmas
  checkpatch: reduce false positives when checking void function return statements
  ia64: arch/ia64/include/uapi/asm/fcntl.h needs personality.h
  DMA, CMA: fix possible memory leak
  slab: fix oops when reading /proc/slab_allocators
  shmem: fix faulting into a hole while it's punched
  mm: let mm_find_pmd fix buggy race with THP fault
  mm: thp: fix DEBUG_PAGEALLOC oops in copy_page_rep()
  kernel/watchdog.c: print traces for all cpus on lockup detection
  nmi: provide the option to issue an NMI back trace to every cpu but current
  Documentation/accounting/getdelays.c: add missing null-terminate after strncpy call
  ...

When workqueue is delayed, it may occur that a lockres is purged while it
is still queued for master assert.  it may trigger BUG() as follows.

N1                                         N2
dlm_get_lockres()
->dlm_do_master_requery
                                  is the master of lockres,
                                  so queue assert_master work

                                  dlm_thread() start running
                                  and purge the lockres

                                  dlm_assert_master_worker()
                                  send assert master message
                                  to other nodes
receiving the assert_master
message, set master to N2

dlmlock_remote() send create_lock message to N2, but receive DLM_IVLOCKID,
if it is RECOVERY lockres, it triggers the BUG().

Another BUG() is triggered when N3 become the new master and send
assert_master to N1, N1 will trigger the BUG() because owner doesn't
match.  So we should not purge lockres when it is queued for assert
master.
Signed-off-by: Njoyce.xue <xuejiufei@huawei.com>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The following case may lead to endless loop during umount.

node A         node B               node C       node D
umount volume,
migrate lockres1
to B
                                                 want to lock lockres1,
                                                 send
                                                 MASTER_REQUEST_MSG
                                                 to C
                                    init block mle
               send
               MIGRATE_REQUEST_MSG
               to C
                                    find a block
                                    mle, and then
                                    return
                                    DLM_MIGRATE_RESPONSE_MASTERY_REF
                                    to B
               set C in refmap
                                    umount successfully
               try to umount, endless
               loop occurs when migrate
               lockres1 since C is in
               refmap

So we can fix this endless loop case by only returning
DLM_MIGRATE_RESPONSE_MASTERY_REF if it has a mastery mle when receiving
MIGRATE_REQUEST_MSG.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Njiangyiwen <jiangyiwen@huawei.com>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Xue jiufei <xuejiufei@huawei.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When the call to ocfs2_add_entry() failed in ocfs2_symlink() and
ocfs2_mknod(), iput() will not be called during dput(dentry) because no
d_instantiate(), and this will lead to umount hung.
Signed-off-by: Njiangyiwen <jiangyiwen@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When running dirop_fileop_racer we found a dead lock case.

2 nodes, say Node A and Node B, mount the same ocfs2 volume.  Create
/race/16/1 in the filesystem, and let the inode number of dir 16 is less
than the inode number of dir race.

Node A                            Node B
mv /race/16/1 /race/
                                  right after Node A has got the
                                  EX mode of /race/16/, and tries to
                                  get EX mode of /race
                                  ls /race/16/

In this case, Node A has got the EX mode of /race/16/, and wants to get EX
mode of /race/.  Node B has got the PR mode of /race/, and wants to get
the PR mode of /race/16/.  Since EX and PR are mutually exclusive, dead
lock happens.

This patch fixes this case by locking in ancestor order before trying
inode number order.
Signed-off-by: NYiwen Jiang <jiangyiwen@huawei.com>
Signed-off-by: NJoseph Qi <joseph.qi@huawei.com>
Cc: Joel Becker <jlbec@evilplan.org>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When a lockres in purge list but is still in use, it should be moved to
the tail of purge list.  dlm_thread will continue to check next lockres in
purge list.  However, code list_move_tail(&dlm->purge_list,
&lockres->purge) will do *no* movements, so dlm_thread will purge the same
lockres in this loop again and again.  If it is in use for a long time,
other lockres will not be processed.
Signed-off-by: NYiwen Jiang <jiangyiwen@huawei.com>
Signed-off-by: Njoyce.xue <xuejiufei@huawei.com>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch tries to fix this crash:

 #5 [ffff88003c1cd690] do_invalid_op at ffffffff810166d5
 #6 [ffff88003c1cd730] invalid_op at ffffffff8159b2de
    [exception RIP: ocfs2_direct_IO_get_blocks+359]
    RIP: ffffffffa05dfa27  RSP: ffff88003c1cd7e8  RFLAGS: 00010202
    RAX: 0000000000000000  RBX: ffff88003c1cdaa8  RCX: 0000000000000000
    RDX: 000000000000000c  RSI: ffff880027a95000  RDI: ffff88003c79b540
    RBP: ffff88003c1cd858   R8: 0000000000000000   R9: ffffffff815f6ba0
    R10: 00000000000001c9  R11: 00000000000001c9  R12: ffff88002d271500
    R13: 0000000000000001  R14: 0000000000000000  R15: 0000000000001000
    ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
 #7 [ffff88003c1cd860] do_direct_IO at ffffffff811cd31b
 #8 [ffff88003c1cd950] direct_IO_iovec at ffffffff811cde9c
 #9 [ffff88003c1cd9b0] do_blockdev_direct_IO at ffffffff811ce764
#10 [ffff88003c1cdb80] __blockdev_direct_IO at ffffffff811ce7cc
#11 [ffff88003c1cdbb0] ocfs2_direct_IO at ffffffffa05df756 [ocfs2]
#12 [ffff88003c1cdbe0] generic_file_direct_write_iter at ffffffff8112f935
#13 [ffff88003c1cdc40] ocfs2_file_write_iter at ffffffffa0600ccc [ocfs2]
#14 [ffff88003c1cdd50] do_aio_write at ffffffff8119126c
#15 [ffff88003c1cddc0] aio_rw_vect_retry at ffffffff811d9bb4
#16 [ffff88003c1cddf0] aio_run_iocb at ffffffff811db880
#17 [ffff88003c1cde30] io_submit_one at ffffffff811dc238
#18 [ffff88003c1cde80] do_io_submit at ffffffff811dc437
#19 [ffff88003c1cdf70] sys_io_submit at ffffffff811dc530
#20 [ffff88003c1cdf80] system_call_fastpath at ffffffff8159a159

It crashes at
        BUG_ON(create && (ext_flags & OCFS2_EXT_REFCOUNTED));
in ocfs2_direct_IO_get_blocks.

ocfs2_direct_IO_get_blocks is expecting the OCFS2_EXT_REFCOUNTED be removed in
ocfs2_prepare_inode_for_write() if it was there. But no cluster lock is taken
during the time before (or inside) ocfs2_prepare_inode_for_write() and after
ocfs2_direct_IO_get_blocks().

It can happen in this case:

Node A(which crashes)				Node B
------------------------                 ---------------------------
ocfs2_file_aio_write
  ocfs2_prepare_inode_for_write
    ocfs2_inode_lock
    ...
    ocfs2_inode_unlock
  #no refcount found
....					ocfs2_reflink
                                          ocfs2_inode_lock
                                          ...
                                          ocfs2_inode_unlock
                                          #now, refcount flag set on extent

                                        ...
                                        flush change to disk

ocfs2_direct_IO_get_blocks
  ocfs2_get_clusters
    #extent map miss
    #buffer_head miss
    read extents from disk
  found refcount flag on extent
  crash..

Fix:
Take rw_lock in ocfs2_reflink path
Signed-off-by: NWengang Wang <wen.gang.wang@oracle.com>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

75f82eaa ("ocfs2: fix NULL pointer dereference when dismount and
ocfs2rec simultaneously") may cause umount hang while shutting down
truncate log.

The situation is as followes:
ocfs2_dismout_volume
-> ocfs2_recovery_exit
  -> free osb->recovery_map
-> ocfs2_truncate_shutdown
  -> lock global bitmap inode
    -> ocfs2_wait_for_recovery
          -> check whether osb->recovery_map->rm_used is zero

Because osb->recovery_map is already freed, rm_used can be any other
values, so it may yield umount hang.
Signed-off-by: Njoyce.xue <xuejiufei@huawei.com>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

ocfs2: fix deadlock when two nodes are converting same lock from PR to EX and idletimeout closes conn

Orabug: 18639535

Two node cluster and both nodes hold a lock at PR level and both want to
convert to EX at the same time.  Master node 1 has sent BAST and then
closes the connection due to idletime out.  Node 0 receives BAST, sends
unlock req with cancel flag but gets error -ENOTCONN.  The problem is
this error is ignored in dlm_send_remote_unlock_request() on the
**incorrect** assumption that the master is dead.  See NOTE in comment
why it returns DLM_NORMAL.  Upon getting DLM_NORMAL, node 0 proceeds to
sends convert (without cancel flg) which fails with -ENOTCONN.  waits 5
sec and resends.

This time gets DLM_IVLOCKID from the master since lock not found in
grant, it had been moved to converting queue in response to conv PR->EX
req.  No way out.

Node 1 (master)				Node 0
==============				======

  lock mode PR				PR

  convert PR -> EX
  mv grant -> convert and que BAST
  ...
                     <-------- convert PR -> EX
  convert que looks like this: ((node 1, PR -> EX) (node 0, PR -> EX))
  ...
                        BAST (want PR -> NL)
                     ------------------>
  ...
  idle timout, conn closed
                                ...
                                In response to BAST,
                                sends unlock with cancel convert flag
                                gets -ENOTCONN. Ignores and
                                sends remote convert request
                                gets -ENOTCONN, waits 5 Sec, retries
  ...
  reconnects
                   <----------------- convert req goes through on next try
  does not find lock on grant que
                   status DLM_IVLOCKID
                   ------------------>
  ...

No way out.  Fix is to keep retrying unlock with cancel flag until it
succeeds or the master dies.
Signed-off-by: NTariq Saeed <tariq.x.saeed@oracle.com>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There are two files a and b in dir /mnt/ocfs2.

    node A                           node B

  mv a b
  In ocfs2_rename(), after calling
  ocfs2_orphan_add(), the inode of
  file b will be added into orphan
  dir.

  If ocfs2_update_entry() fails,
  ocfs2_rename return error and mv
  operation fails. But file b still
  exists in the parent dir.

  ocfs2_queue_orphan_scan
   -> ocfs2_queue_recovery_completion
   -> ocfs2_complete_recovery
   -> ocfs2_recover_orphans
  The inode of the file b will be
  put with iput().

  ocfs2_evict_inode
   -> ocfs2_delete_inode
   -> ocfs2_wipe_inode
   -> ocfs2_remove_inode
  OCFS2_VALID_FL in the inode
  i_flags will be cleared.

                                   The file b still can be accessed
                                   on node B.
                                   ls /mnt/ocfs2
                                   When first read the file b with
                                   ocfs2_read_inode_block(). It will
                                   validate the inode using
                                   ocfs2_validate_inode_block().
                                   Because OCFS2_VALID_FL not set in
                                   the inode i_flags, so the file
                                   system will be readonly.

So we should add inode into orphan dir after updating entry in
ocfs2_rename().
Signed-off-by: Nalex.chen <alex.chen@huawei.com>
Reviewed-by: NMark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In v2.6.34 commit 9d8cebd4 ("mm: fix mbind vma merge problem")
introduced vma merging to mbind(), but it should have also changed the
convention of passing start vma from queue_pages_range() (formerly
check_range()) to new_vma_page(): vma merging may have already freed
that structure, resulting in BUG at mm/mempolicy.c:1738 and probably
worse crashes.

Fixes: 9d8cebd4 ("mm: fix mbind vma merge problem")
Reported-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Tested-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: NHugh Dickins <hughd@google.com>
Acked-by: NChristoph Lameter <cl@linux.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Minchan Kim <minchan.kim@gmail.com>
Cc: <stable@vger.kernel.org>	[2.6.34+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The previous patch had a few too many false positives on styles that
should be acceptable.
Signed-off-by: NJoe Perches <joe@perches.com>
Tested-by: NAnish Bhatt <anish@chelsio.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

fs/notify/fanotify/fanotify_user.c: In function 'SYSC_fanotify_init':
fs/notify/fanotify/fanotify_user.c:726: error: implicit declaration of function 'personality'
fs/notify/fanotify/fanotify_user.c:726: error: 'PER_LINUX32' undeclared (first use in this function)
fs/notify/fanotify/fanotify_user.c:726: error: (Each undeclared identifier is reported only once
fs/notify/fanotify/fanotify_user.c:726: error: for each function it appears in.)
Reported-by: NWu Fengguang <fengguang.wu@intel.com>
Cc: Will Woods <wwoods@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: <stable@vger.kernel.org>	[3.15.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We should free memory for bitmap when we find zone mismatch, otherwise
this memory will leak.

Additionally, I copy code comment from PPC KVM's CMA code to inform why
we need to check zone mis-match.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: NZhang Yanfei <zhangyanfei@cn.fujitsu.com>
Reviewed-by: NMichal Nazarewicz <mina86@mina86.com>
Reviewed-by: NAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Alexander Graf <agraf@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit b1cb0982 ("change the management method of free objects of
the slab") introduced a bug on slab leak detector
('/proc/slab_allocators').  This detector works like as following
decription.

 1. traverse all objects on all the slabs.
 2. determine whether it is active or not.
 3. if active, print who allocate this object.

but that commit changed the way how to manage free objects, so the logic
determining whether it is active or not is also changed.  In before, we
regard object in cpu caches as inactive one, but, with this commit, we
mistakenly regard object in cpu caches as active one.

This intoduces kernel oops if DEBUG_PAGEALLOC is enabled.  If
DEBUG_PAGEALLOC is enabled, kernel_map_pages() is used to detect who
corrupt free memory in the slab.  It unmaps page table mapping if object
is free and map it if object is active.  When slab leak detector check
object in cpu caches, it mistakenly think this object active so try to
access object memory to retrieve caller of allocation.  At this point,
page table mapping to this object doesn't exist, so oops occurs.

Following is oops message reported from Dave.

It blew up when something tried to read /proc/slab_allocators
(Just cat it, and you should see the oops below)

  Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
  Modules linked in:
  [snip...]
  CPU: 1 PID: 9386 Comm: trinity-c33 Not tainted 3.14.0-rc5+ #131
  task: ffff8801aa46e890 ti: ffff880076924000 task.ti: ffff880076924000
  RIP: 0010:[<ffffffffaa1a8f4a>]  [<ffffffffaa1a8f4a>] handle_slab+0x8a/0x180
  RSP: 0018:ffff880076925de0  EFLAGS: 00010002
  RAX: 0000000000001000 RBX: 0000000000000000 RCX: 000000005ce85ce7
  RDX: ffffea00079be100 RSI: 0000000000001000 RDI: ffff880107458000
  RBP: ffff880076925e18 R08: 0000000000000001 R09: 0000000000000000
  R10: 0000000000000000 R11: 000000000000000f R12: ffff8801e6f84000
  R13: ffffea00079be100 R14: ffff880107458000 R15: ffff88022bb8d2c0
  FS:  00007fb769e45740(0000) GS:ffff88024d040000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffff8801e6f84ff8 CR3: 00000000a22db000 CR4: 00000000001407e0
  DR0: 0000000002695000 DR1: 0000000002695000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000070602
  Call Trace:
    leaks_show+0xce/0x240
    seq_read+0x28e/0x490
    proc_reg_read+0x3d/0x80
    vfs_read+0x9b/0x160
    SyS_read+0x58/0xb0
    tracesys+0xd4/0xd9
  Code: f5 00 00 00 0f 1f 44 00 00 48 63 c8 44 3b 0c 8a 0f 84 e3 00 00 00 83 c0 01 44 39 c0 72 eb 41 f6 47 1a 01 0f 84 e9 00 00 00 89 f0 <4d> 8b 4c 04 f8 4d 85 c9 0f 84 88 00 00 00 49 8b 7e 08 4d 8d 46
  RIP   handle_slab+0x8a/0x180

To fix the problem, I introduce an object status buffer on each slab.
With this, we can track object status precisely, so slab leak detector
would not access active object and no kernel oops would occur.  Memory
overhead caused by this fix is only imposed to CONFIG_DEBUG_SLAB_LEAK
which is mainly used for debugging, so memory overhead isn't big
problem.
Signed-off-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Reported-by: NDave Jones <davej@redhat.com>
Reported-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: NVladimir Davydov <vdavydov@parallels.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@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>

Trinity finds that mmap access to a hole while it's punched from shmem
can prevent the madvise(MADV_REMOVE) or fallocate(FALLOC_FL_PUNCH_HOLE)
from completing, until the reader chooses to stop; with the puncher's
hold on i_mutex locking out all other writers until it can complete.

It appears that the tmpfs fault path is too light in comparison with its
hole-punching path, lacking an i_data_sem to obstruct it; but we don't
want to slow down the common case.

Extend shmem_fallocate()'s existing range notification mechanism, so
shmem_fault() can refrain from faulting pages into the hole while it's
punched, waiting instead on i_mutex (when safe to sleep; or repeatedly
faulting when not).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NHugh Dickins <hughd@google.com>
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Tested-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Dave Jones <davej@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Trinity has reported:

    BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
    IP: __lock_acquire (kernel/locking/lockdep.c:3070 (discriminator 1))
    CPU: 6 PID: 16173 Comm: trinity-c364 Tainted: G        W
                            3.15.0-rc1-next-20140415-sasha-00020-gaa90d09 #398
    lock_acquire (arch/x86/include/asm/current.h:14
                  kernel/locking/lockdep.c:3602)
    _raw_spin_lock (include/linux/spinlock_api_smp.h:143
                    kernel/locking/spinlock.c:151)
    remove_migration_pte (mm/migrate.c:137)
    rmap_walk (mm/rmap.c:1628 mm/rmap.c:1699)
    remove_migration_ptes (mm/migrate.c:224)
    migrate_pages (mm/migrate.c:922 mm/migrate.c:960 mm/migrate.c:1126)
    migrate_misplaced_page (mm/migrate.c:1733)
    __handle_mm_fault (mm/memory.c:3762 mm/memory.c:3812 mm/memory.c:3925)
    handle_mm_fault (mm/memory.c:3948)
    __get_user_pages (mm/memory.c:1851)
    __mlock_vma_pages_range (mm/mlock.c:255)
    __mm_populate (mm/mlock.c:711)
    SyS_mlockall (include/linux/mm.h:1799 mm/mlock.c:817 mm/mlock.c:791)

I believe this comes about because, whereas collapsing and splitting THP
functions take anon_vma lock in write mode (which excludes concurrent
rmap walks), faulting THP functions (write protection and misplaced
NUMA) do not - and mostly they do not need to.

But they do use a pmdp_clear_flush(), set_pmd_at() sequence which, for
an instant (indeed, for a long instant, given the inter-CPU TLB flush in
there), leaves *pmd neither present not trans_huge.

Which can confuse a concurrent rmap walk, as when removing migration
ptes, seen in the dumped trace.  Although that rmap walk has a 4k page
to insert, anon_vmas containing THPs are in no way segregated from
4k-page anon_vmas, so the 4k-intent mm_find_pmd() does need to cope with
that instant when a trans_huge pmd is temporarily absent.

I don't think we need strengthen the locking at the THP end: it's easily
handled with an ACCESS_ONCE() before testing both conditions.

And since mm_find_pmd() had only one caller who wanted a THP rather than
a pmd, let's slightly repurpose it to fail when it hits a THP or
non-present pmd, and open code split_huge_page_address() again.
Signed-off-by: NHugh Dickins <hughd@google.com>
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Lameter <cl@gentwo.org>
Cc: Dave Jones <davej@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Trinity has for over a year been reporting a CONFIG_DEBUG_PAGEALLOC oops
in copy_page_rep() called from copy_user_huge_page() called from
do_huge_pmd_wp_page().

I believe this is a DEBUG_PAGEALLOC false positive, due to the source
page being split, and a tail page freed, while copy is in progress; and
not a problem without DEBUG_PAGEALLOC, since the pmd_same() check will
prevent a miscopy from being made visible.

Fix by adding get_user_huge_page() and put_user_huge_page(): reducing to
the usual get_page() and put_page() on head page in the usual config;
but get and put references to all of the tail pages when
DEBUG_PAGEALLOC.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NHugh Dickins <hughd@google.com>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reported-by: NSasha Levin <sasha.levin@oracle.com>
Tested-by: NSasha Levin <sasha.levin@oracle.com>
Cc: Dave Jones <davej@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A 'softlockup' is defined as a bug that causes the kernel to loop in
kernel mode for more than a predefined period to time, without giving
other tasks a chance to run.

Currently, upon detection of this condition by the per-cpu watchdog
task, debug information (including a stack trace) is sent to the system
log.

On some occasions, we have observed that the "victim" rather than the
actual "culprit" (i.e.  the owner/holder of the contended resource) is
reported to the user.  Often this information has proven to be
insufficient to assist debugging efforts.

To avoid loss of useful debug information, for architectures which
support NMI, this patch makes it possible to improve soft lockup
reporting.  This is accomplished by issuing an NMI to each cpu to obtain
a stack trace.

If NMI is not supported we just revert back to the old method.  A sysctl
and boot-time parameter is available to toggle this feature.

[dzickus@redhat.com: add CONFIG_SMP in certain areas]
[akpm@linux-foundation.org: additional CONFIG_SMP=n optimisations]
[mq@suse.cz: fix warning]
Signed-off-by: NAaron Tomlin <atomlin@redhat.com>
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NJan Moskyto Matejka <mq@suse.cz>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Sometimes it is preferred not to use the trigger_all_cpu_backtrace()
routine when one wants to avoid capturing a back trace for current.  For
instance if one was previously captured recently.

This patch provides a new routine namely
trigger_allbutself_cpu_backtrace() which offers the flexibility to issue
an NMI to every cpu but current and capture a back trace accordingly.

Patch x86 and sparc to support new routine.

[dzickus@redhat.com: add stub in #else clause]
[dzickus@redhat.com: don't print message in single processor case, wrap with get/put_cpu based on Oleg's suggestion]
[sfr@canb.auug.org.au: undo C99ism]
Signed-off-by: NAaron Tomlin <atomlin@redhat.com>
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Cc: Mateusz Guzik <mguzik@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Added a guaranteed null-terminate after call to strncpy.

This was partly found using a static code analysis program called
cppcheck.
Signed-off-by: NRickard Strandqvist <rickard_strandqvist@spectrumdigital.se>
Acked-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Add cancel_work_sync() in rtsx_pci_ms_drv_remove() to cancel pending
request work when removing the driver.
Signed-off-by: NMicky Ching <micky_ching@realsil.com.cn>
Cc: Samuel Ortiz <sameo@linux.intel.com> says:
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Alex Dubov <oakad@yahoo.com>
Cc: Roger Tseng <rogerable@realtek.com>
Cc: Wei WANG <wei_wang@realsil.com.cn>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Oleg reports a division by zero error on zero-length write() to the
percpu_pagelist_fraction sysctl:

    divide error: 0000 [#1] SMP DEBUG_PAGEALLOC
    CPU: 1 PID: 9142 Comm: badarea_io Not tainted 3.15.0-rc2-vm-nfs+ #19
    Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
    task: ffff8800d5aeb6e0 ti: ffff8800d87a2000 task.ti: ffff8800d87a2000
    RIP: 0010: percpu_pagelist_fraction_sysctl_handler+0x84/0x120
    RSP: 0018:ffff8800d87a3e78  EFLAGS: 00010246
    RAX: 0000000000000f89 RBX: ffff88011f7fd000 RCX: 0000000000000000
    RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000010
    RBP: ffff8800d87a3e98 R08: ffffffff81d002c8 R09: ffff8800d87a3f50
    R10: 000000000000000b R11: 0000000000000246 R12: 0000000000000060
    R13: ffffffff81c3c3e0 R14: ffffffff81cfddf8 R15: ffff8801193b0800
    FS:  00007f614f1e9740(0000) GS:ffff88011f440000(0000) knlGS:0000000000000000
    CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
    CR2: 00007f614f1fa000 CR3: 00000000d9291000 CR4: 00000000000006e0
    Call Trace:
      proc_sys_call_handler+0xb3/0xc0
      proc_sys_write+0x14/0x20
      vfs_write+0xba/0x1e0
      SyS_write+0x46/0xb0
      tracesys+0xe1/0xe6

However, if the percpu_pagelist_fraction sysctl is set by the user, it
is also impossible to restore it to the kernel default since the user
cannot write 0 to the sysctl.

This patch allows the user to write 0 to restore the default behavior.
It still requires a fraction equal to or larger than 8, however, as
stated by the documentation for sanity.  If a value in the range [1, 7]
is written, the sysctl will return EINVAL.

This successfully solves the divide by zero issue at the same time.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Reported-by: NOleg Drokin <green@linuxhacker.ru>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The related warning:

  scripts/kconfig/conf --allmodconfig Kconfig
  warning: (FAULT_INJECTION_STACKTRACE_FILTER && LATENCYTOP && KMEMCHECK && LOCKDEP) selects FRAME_POINTER which has unmet direct dependencies (DEBUG_KERNEL && (CRIS || M68K || FRV || UML || AVR32 || SUPERH || BLACKFIN || MN10300 || METAG) || ARCH_WANT_FRAME_POINTERS)
Signed-off-by: NChen Gang <gang.chen.5i5j@gmail.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Peter Wu noticed the following splat on his machine when updating
/proc/sys/kernel/watchdog_thresh:

  BUG: sleeping function called from invalid context at mm/slub.c:965
  in_atomic(): 1, irqs_disabled(): 0, pid: 1, name: init
  3 locks held by init/1:
   #0:  (sb_writers#3){.+.+.+}, at: [<ffffffff8117b663>] vfs_write+0x143/0x180
   #1:  (watchdog_proc_mutex){+.+.+.}, at: [<ffffffff810e02d3>] proc_dowatchdog+0x33/0x110
   #2:  (cpu_hotplug.lock){.+.+.+}, at: [<ffffffff810589c2>] get_online_cpus+0x32/0x80
  Preemption disabled at:[<ffffffff810e0384>] proc_dowatchdog+0xe4/0x110

  CPU: 0 PID: 1 Comm: init Not tainted 3.16.0-rc1-testing #34
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
  Call Trace:
    dump_stack+0x4e/0x7a
    __might_sleep+0x11d/0x190
    kmem_cache_alloc_trace+0x4e/0x1e0
    perf_event_alloc+0x55/0x440
    perf_event_create_kernel_counter+0x26/0xe0
    watchdog_nmi_enable+0x75/0x140
    update_timers_all_cpus+0x53/0xa0
    proc_dowatchdog+0xe4/0x110
    proc_sys_call_handler+0xb3/0xc0
    proc_sys_write+0x14/0x20
    vfs_write+0xad/0x180
    SyS_write+0x49/0xb0
    system_call_fastpath+0x16/0x1b
  NMI watchdog: disabled (cpu0): hardware events not enabled

What happened is after updating the watchdog_thresh, the lockup detector
is restarted to utilize the new value.  Part of this process involved
disabling preemption.  Once preemption was disabled, perf tried to
allocate a new event (as part of the restart).  This caused the above
BUG_ON as you can't sleep with preemption disabled.

The preemption restriction seemed agressive as we are not doing anything
on that particular cpu, but with all the online cpus (which are
protected by the get_online_cpus lock).  Remove the restriction and the
BUG_ON goes away.
Signed-off-by: NDon Zickus <dzickus@redhat.com>
Acked-by: NMichal Hocko <mhocko@suse.cz>
Reported-by: NPeter Wu <peter@lekensteyn.nl>
Tested-by: NPeter Wu <peter@lekensteyn.nl>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>		[3.13+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

As discussed in various threads on the side:

Remove one inactive maintainer, add two new ones and update my email
address.  Plus add Andrew.  And fix the glob to include files like
mm/slab_common.c
Signed-off-by: NChristoph Lameter <cl@linux.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Acked-by: NJoonsoo Kim <iamjoonsoo.kim@lge.com>
Acked-by: NPekka Enberg <penberg@kernel.org>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's a race between fork() and hugepage migration, as a result we try
to "dereference" a swap entry as a normal pte, causing kernel panic.
The cause of the problem is that copy_hugetlb_page_range() can't handle
"swap entry" family (migration entry and hwpoisoned entry) so let's fix
it.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: NHugh Dickins <hughd@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: <stable@vger.kernel.org>	[2.6.37+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

I was well aware of FALLOC_FL_ZERO_RANGE and FALLOC_FL_COLLAPSE_RANGE
support being added to fallocate(); but didn't realize until now that I
had been too stupid to future-proof shmem_fallocate() against new
additions.  -EOPNOTSUPP instead of going on to ordinary fallocation.
Signed-off-by: NHugh Dickins <hughd@google.com>
Reviewed-by: NLukas Czerner <lczerner@redhat.com>
Cc: <stable@vger.kernel.org>	[3.15]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Documentation/memory-hotplug.txt incorrectly states that the memory
driver "probe" interface is only supported on powerpc and is vague about
its application on x86.  Clarify the platforms that make this interface
available if memory hotplug is enabled.
Signed-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

To allow filtering of huge pages, makedumpfile must be able to identify
them in the dump.  This can be done by checking the appropriate page
flag, so communicate its value to makedumpfile through the VMCOREINFO
interface.

There's only one small catch.  Depending on how many page flags are
available on a given architecture, this bit can be called PG_head or
PG_compound.

I sent a similar patch back in 2012, but Eric Biederman did not like
using an #ifdef.  So, this time I'm adding a common symbol
(PG_head_mask) instead.

See https://lkml.org/lkml/2012/11/28/91 for the previous version.
Signed-off-by: NPetr Tesarik <ptesarik@suse.cz>
Acked-by: NVivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is a race between the CPU offline code (within stop-machine) and
the smp-call-function code, which can lead to getting IPIs on the
outgoing CPU, *after* it has gone offline.

Specifically, this can happen when using
smp_call_function_single_async() to send the IPI, since this API allows
sending asynchronous IPIs from IRQ disabled contexts.  The exact race
condition is described below.

During CPU offline, in stop-machine, we don't enforce any rule in the
_DISABLE_IRQ stage, regarding the order in which the outgoing CPU and
the other CPUs disable their local interrupts.  Due to this, we can
encounter a situation in which an IPI is sent by one of the other CPUs
to the outgoing CPU (while it is *still* online), but the outgoing CPU
ends up noticing it only *after* it has gone offline.

              CPU 1                                         CPU 2
          (Online CPU)                               (CPU going offline)

       Enter _PREPARE stage                          Enter _PREPARE stage

                                                     Enter _DISABLE_IRQ stage

                                                   =
       Got a device interrupt, and                 | Didn't notice the IPI
       the interrupt handler sent an               | since interrupts were
       IPI to CPU 2 using                          | disabled on this CPU.
       smp_call_function_single_async()            |
                                                   =

       Enter _DISABLE_IRQ stage

       Enter _RUN stage                              Enter _RUN stage

                                  =
       Busy loop with interrupts  |                  Invoke take_cpu_down()
       disabled.                  |                  and take CPU 2 offline
                                  =

       Enter _EXIT stage                             Enter _EXIT stage

       Re-enable interrupts                          Re-enable interrupts

                                                     The pending IPI is noted
                                                     immediately, but alas,
                                                     the CPU is offline at
                                                     this point.

This of course, makes the smp-call-function IPI handler code running on
CPU 2 unhappy and it complains about "receiving an IPI on an offline
CPU".

One real example of the scenario on CPU 1 is the block layer's
complete-request call-path:

	__blk_complete_request() [interrupt-handler]
	    raise_blk_irq()
	        smp_call_function_single_async()

However, if we look closely, the block layer does check that the target
CPU is online before firing the IPI.  So in this case, it is actually
the unfortunate ordering/timing of events in the stop-machine phase that
leads to receiving IPIs after the target CPU has gone offline.

In reality, getting a late IPI on an offline CPU is not too bad by
itself (this can happen even due to hardware latencies in IPI
send-receive).  It is a bug only if the target CPU really went offline
without executing all the callbacks queued on its list.  (Note that a
CPU is free to execute its pending smp-call-function callbacks in a
batch, without waiting for the corresponding IPIs to arrive for each one
of those callbacks).

So, fixing this issue can be broken up into two parts:

1. Ensure that a CPU goes offline only after executing all the
   callbacks queued on it.

2. Modify the warning condition in the smp-call-function IPI handler
   code such that it warns only if an offline CPU got an IPI *and* that
   CPU had gone offline with callbacks still pending in its queue.

Achieving part 1 is straight-forward - just flush (execute) all the
queued callbacks on the outgoing CPU in the CPU_DYING stage[1],
including those callbacks for which the source CPU's IPIs might not have
been received on the outgoing CPU yet.  Once we do this, an IPI that
arrives late on the CPU going offline (either due to the race mentioned
above, or due to hardware latencies) will be completely harmless, since
the outgoing CPU would have executed all the queued callbacks before
going offline.

Overall, this fix (parts 1 and 2 put together) additionally guarantees
that we will see a warning only when the *IPI-sender code* is buggy -
that is, if it queues the callback _after_ the target CPU has gone
offline.

[1].  The CPU_DYING part needs a little more explanation: by the time we
execute the CPU_DYING notifier callbacks, the CPU would have already
been marked offline.  But we want to flush out the pending callbacks at
this stage, ignoring the fact that the CPU is offline.  So restructure
the IPI handler code so that we can by-pass the "is-cpu-offline?" check
in this particular case.  (Of course, the right solution here is to fix
CPU hotplug to mark the CPU offline _after_ invoking the CPU_DYING
notifiers, but this requires a lot of audit to ensure that this change
doesn't break any existing code; hence lets go with the solution
proposed above until that is done).

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Suggested-by: NFrederic Weisbecker <fweisbec@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Galbraith <mgalbraith@suse.de>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: NSachin Kamat <sachin.kamat@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm could be removed from current task struct, using previous vma->vm_mm

It will crash on blackfin after updated to Linux 3.15.  The commit "mm:
per-thread vma caching" caused the crash.  mm could be removed from
current task struct before

  mmput()->
    exit_mmap()->
      delete_vma_from_mm()

the detailed fault information:

    NULL pointer access
    Kernel OOPS in progress
    Deferred Exception context
    CURRENT PROCESS:
    COMM=modprobe PID=278  CPU=0
    invalid mm
    return address: [0x000531de]; contents of:
    0x000531b0:  c727  acea  0c42  181d  0000  0000  0000  a0a8
    0x000531c0:  b090  acaa  0c42  1806  0000  0000  0000  a0e8
    0x000531d0:  b0d0  e801  0000  05b3  0010  e522  0046 [a090]
    0x000531e0:  6408  b090  0c00  17cc  3042  e3ff  f37b  2fc8

    CPU: 0 PID: 278 Comm: modprobe Not tainted 3.15.0-ADI-2014R1-pre-00345-gea9f446 #25
    task: 0572b720 ti: 0569e000 task.ti: 0569e000
    Compiled for cpu family 0x27fe (Rev 0), but running on:0x0000 (Rev 0)
    ADSP-BF609-0.0 500(MHz CCLK) 125(MHz SCLK) (mpu off)
    Linux version 3.15.0-ADI-2014R1-pre-00345-gea9f446 (steven@steven-OptiPlex-390) (gcc version 4.3.5 (ADI-trunk/svn-5962) ) #25 Tue Jun 10 17:47:46 CST 2014

    SEQUENCER STATUS:		Not tainted
     SEQSTAT: 00000027  IPEND: 8008  IMASK: ffff  SYSCFG: 2806
      EXCAUSE   : 0x27
      physical IVG3 asserted : <0xffa00744> { _trap + 0x0 }
      physical IVG15 asserted : <0xffa00d68> { _evt_system_call + 0x0 }
      logical irq   6 mapped  : <0xffa003bc> { _bfin_coretmr_interrupt + 0x0 }
      logical irq   7 mapped  : <0x00008828> { _bfin_fault_routine + 0x0 }
      logical irq  11 mapped  : <0x00007724> { _l2_ecc_err + 0x0 }
      logical irq  13 mapped  : <0x00008828> { _bfin_fault_routine + 0x0 }
      logical irq  39 mapped  : <0x00150788> { _bfin_twi_interrupt_entry + 0x0 }
      logical irq  40 mapped  : <0x00150788> { _bfin_twi_interrupt_entry + 0x0 }
     RETE: <0x00000000> /* Maybe null pointer? */
     RETN: <0x0569fe50> /* kernel dynamic memory (maybe user-space) */
     RETX: <0x00000480> /* Maybe fixed code section */
     RETS: <0x00053384> { _exit_mmap + 0x28 }
     PC  : <0x000531de> { _delete_vma_from_mm + 0x92 }
    DCPLB_FAULT_ADDR: <0x00000008> /* Maybe null pointer? */
    ICPLB_FAULT_ADDR: <0x000531de> { _delete_vma_from_mm + 0x92 }
    PROCESSOR STATE:
     R0 : 00000004    R1 : 0569e000    R2 : 00bf3db4    R3 : 00000000
     R4 : 057f9800    R5 : 00000001    R6 : 0569ddd0    R7 : 0572b720
     P0 : 0572b854    P1 : 00000004    P2 : 00000000    P3 : 0569dda0
     P4 : 0572b720    P5 : 0566c368    FP : 0569fe5c    SP : 0569fd74
     LB0: 057f523f    LT0: 057f523e    LC0: 00000000
     LB1: 0005317c    LT1: 00053172    LC1: 00000002
     B0 : 00000000    L0 : 00000000    M0 : 0566f5bc    I0 : 00000000
     B1 : 00000000    L1 : 00000000    M1 : 00000000    I1 : ffffffff
     B2 : 00000001    L2 : 00000000    M2 : 00000000    I2 : 00000000
     B3 : 00000000    L3 : 00000000    M3 : 00000000    I3 : 057f8000
    A0.w: 00000000   A0.x: 00000000   A1.w: 00000000   A1.x: 00000000
    USP : 056ffcf8  ASTAT: 02003024

    Hardware Trace:
       0 Target : <0x00003fb8> { _trap_c + 0x0 }
         Source : <0xffa006d8> { _exception_to_level5 + 0xa0 } JUMP.L
       1 Target : <0xffa00638> { _exception_to_level5 + 0x0 }
         Source : <0xffa004f2> { _bfin_return_from_exception + 0x6 } RTX
       2 Target : <0xffa004ec> { _bfin_return_from_exception + 0x0 }
         Source : <0xffa00590> { _ex_trap_c + 0x70 } JUMP.S
       3 Target : <0xffa00520> { _ex_trap_c + 0x0 }
         Source : <0xffa0076e> { _trap + 0x2a } JUMP (P4)
       4 Target : <0xffa00744> { _trap + 0x0 }
          FAULT : <0x000531de> { _delete_vma_from_mm + 0x92 } P0 = W[P2 + 2]
         Source : <0x000531da> { _delete_vma_from_mm + 0x8e } P2 = [P4 + 0x18]
       5 Target : <0x000531da> { _delete_vma_from_mm + 0x8e }
         Source : <0x00053176> { _delete_vma_from_mm + 0x2a } IF CC JUMP pcrel
       6 Target : <0x0005314c> { _delete_vma_from_mm + 0x0 }
         Source : <0x00053380> { _exit_mmap + 0x24 } JUMP.L
       7 Target : <0x00053378> { _exit_mmap + 0x1c }
         Source : <0x00053394> { _exit_mmap + 0x38 } IF !CC JUMP pcrel (BP)
       8 Target : <0x00053390> { _exit_mmap + 0x34 }
         Source : <0xffa020e0> { __cond_resched + 0x20 } RTS
       9 Target : <0xffa020c0> { __cond_resched + 0x0 }
         Source : <0x0005338c> { _exit_mmap + 0x30 } JUMP.L
      10 Target : <0x0005338c> { _exit_mmap + 0x30 }
         Source : <0x0005333a> { _delete_vma + 0xb2 } RTS
      11 Target : <0x00053334> { _delete_vma + 0xac }
         Source : <0x0005507a> { _kmem_cache_free + 0xba } RTS
      12 Target : <0x00055068> { _kmem_cache_free + 0xa8 }
         Source : <0x0005505e> { _kmem_cache_free + 0x9e } IF !CC JUMP pcrel (BP)
      13 Target : <0x00055052> { _kmem_cache_free + 0x92 }
         Source : <0x0005501a> { _kmem_cache_free + 0x5a } IF CC JUMP pcrel
      14 Target : <0x00054ff4> { _kmem_cache_free + 0x34 }
         Source : <0x00054fce> { _kmem_cache_free + 0xe } IF CC JUMP pcrel (BP)
      15 Target : <0x00054fc0> { _kmem_cache_free + 0x0 }
         Source : <0x00053330> { _delete_vma + 0xa8 } JUMP.L
    Kernel Stack
    Stack info:
     SP: [0x0569ff24] <0x0569ff24> /* kernel dynamic memory (maybe user-space) */
     Memory from 0x0569ff20 to 056a0000
    0569ff20: 00000001 [04e8da5a] 00008000  00000000  00000000  056a0000  04e8da5a  04e8da5a
    0569ff40: 04eb9eea  ffa00dce  02003025  04ea09c5  057f523f  04ea09c4  057f523e  00000000
    0569ff60: 00000000  00000000  00000000  00000000  00000000  00000000  00000001  00000000
    0569ff80: 00000000  00000000  00000000  00000000  00000000  00000000  00000000  00000000
    0569ffa0: 0566f5bc  057f8000  057f8000  00000001  04ec0170  056ffcf8  056ffd04  057f9800
    0569ffc0: 04d1d498  057f9800  057f8fe4  057f8ef0  00000001  057f928c  00000001  00000001
    0569ffe0: 057f9800  00000000  00000008  00000007  00000001  00000001  00000001 <00002806>
    Return addresses in stack:
        address : <0x00002806> { _show_cpuinfo + 0x2d2 }
    Modules linked in:
    Kernel panic - not syncing: Kernel exception
    [ end Kernel panic - not syncing: Kernel exception
Signed-off-by: NSteven Miao <realmz6@gmail.com>
Acked-by: NDavidlohr Bueso <davidlohr@hp.com>
Reviewed-by: NRik van Riel <riel@redhat.com>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: <stable@vger.kernel.org>	[3.15.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Given some pathologically compressed data, lz4 could possibly decide to
wrap a few internal variables, causing unknown things to happen.  Catch
this before the wrapping happens and abort the decompression.
Reported-by: N"Don A. Bailey" <donb@securitymouse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

The lzo decompressor can, if given some really crazy data, possibly
overrun some variable types.  Modify the checking logic to properly
detect overruns before they happen.
Reported-by: N"Don A. Bailey" <donb@securitymouse.com>
Tested-by: N"Don A. Bailey" <donb@securitymouse.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>