Instead of making the files owned by the GLOBAL_ROOT_USER.  Make
non-dumpable files whose mm has always lived in a user namespace owned
by the user namespace root.  This allows the container root to have
things work as expected in a container.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

With previous changes every location that tests for
LSM_UNSAFE_PTRACE_CAP also tests for LSM_UNSAFE_PTRACE making the
LSM_UNSAFE_PTRACE_CAP redundant, so remove it.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Now that we have user namespaces and non-global capabilities verify
the tracer has capabilities in the relevant user namespace instead
of in the current_user_ns().

As the test for setting LSM_UNSAFE_PTRACE_CAP is currently
ptracer_capable(p, current_user_ns()) and the new task credentials are
in current_user_ns() this change does not have any user visible change
and simply moves the test to where it is used, making the code easier
to read.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Don't reset euid and egid when the tracee has CAP_SETUID in
it's user namespace.  I punted on relaxing this permission check
long ago but now that I have read this code closely it is clear
it is safe to test against CAP_SETUID in the user namespace.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

This patchset converts inotify to using the newly introduced
per-userns sysctl infrastructure.

Currently the inotify instances/watches are being accounted in the
user_struct structure. This means that in setups where multiple
users in unprivileged containers map to the same underlying
real user (i.e. pointing to the same user_struct) the inotify limits
are going to be shared as well, allowing one user(or application) to exhaust
all others limits.

Fix this by switching the inotify sysctls to using the
per-namespace/per-user limits. This will allow the server admin to
set sensible global limits, which can further be tuned inside every
individual user namespace. Additionally, in order to preserve the
sysctl ABI make the existing inotify instances/watches sysctls
modify the values of the initial user namespace.
Signed-off-by: Nikolay Borisov <n.borisov.lkml@gmail.com>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Serge Hallyn <serge@hallyn.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

The ucounts_lock is being used to protect various ucounts lifecycle
management functionalities. However, those services can also be invoked
when a pidns is being freed in an RCU callback (e.g. softirq context).
This can lead to deadlocks. There were already efforts trying to
prevent similar deadlocks in add7c65c ("pid: fix lockdep deadlock
warning due to ucount_lock"), however they just moved the context
from hardirq to softrq. Fix this issue once and for all by explictly
making the lock disable irqs altogether.

Dmitry Vyukov <dvyukov@google.com> reported:

> I've got the following deadlock report while running syzkaller fuzzer
> on eec0d3d065bfcdf9cd5f56dd2a36b94d12d32297 of linux-next (on odroid
> device if it matters):
>
> =================================
> [ INFO: inconsistent lock state ]
> 4.10.0-rc3-next-20170112-xc2-dirty #6 Not tainted
> ---------------------------------
> inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
> swapper/2/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
>  (ucounts_lock){+.?...}, at: [<     inline     >] spin_lock
> ./include/linux/spinlock.h:302
>  (ucounts_lock){+.?...}, at: [<ffff2000081678c8>]
> put_ucounts+0x60/0x138 kernel/ucount.c:162
> {SOFTIRQ-ON-W} state was registered at:
> [<ffff2000081c82d8>] mark_lock+0x220/0xb60 kernel/locking/lockdep.c:3054
> [<     inline     >] mark_irqflags kernel/locking/lockdep.c:2941
> [<ffff2000081c97a8>] __lock_acquire+0x388/0x3260 kernel/locking/lockdep.c:3295
> [<ffff2000081cce24>] lock_acquire+0xa4/0x138 kernel/locking/lockdep.c:3753
> [<     inline     >] __raw_spin_lock ./include/linux/spinlock_api_smp.h:144
> [<ffff200009798128>] _raw_spin_lock+0x90/0xd0 kernel/locking/spinlock.c:151
> [<     inline     >] spin_lock ./include/linux/spinlock.h:302
> [<     inline     >] get_ucounts kernel/ucount.c:131
> [<ffff200008167c28>] inc_ucount+0x80/0x6c8 kernel/ucount.c:189
> [<     inline     >] inc_mnt_namespaces fs/namespace.c:2818
> [<ffff200008481850>] alloc_mnt_ns+0x78/0x3a8 fs/namespace.c:2849
> [<ffff200008487298>] create_mnt_ns+0x28/0x200 fs/namespace.c:2959
> [<     inline     >] init_mount_tree fs/namespace.c:3199
> [<ffff200009bd6674>] mnt_init+0x258/0x384 fs/namespace.c:3251
> [<ffff200009bd60bc>] vfs_caches_init+0x6c/0x80 fs/dcache.c:3626
> [<ffff200009bb1114>] start_kernel+0x414/0x460 init/main.c:648
> [<ffff200009bb01e8>] __primary_switched+0x6c/0x70 arch/arm64/kernel/head.S:456
> irq event stamp: 2316924
> hardirqs last  enabled at (2316924): [<     inline     >] rcu_do_batch
> kernel/rcu/tree.c:2911
> hardirqs last  enabled at (2316924): [<     inline     >]
> invoke_rcu_callbacks kernel/rcu/tree.c:3182
> hardirqs last  enabled at (2316924): [<     inline     >]
> __rcu_process_callbacks kernel/rcu/tree.c:3149
> hardirqs last  enabled at (2316924): [<ffff200008210414>]
> rcu_process_callbacks+0x7a4/0xc28 kernel/rcu/tree.c:3166
> hardirqs last disabled at (2316923): [<     inline     >] rcu_do_batch
> kernel/rcu/tree.c:2900
> hardirqs last disabled at (2316923): [<     inline     >]
> invoke_rcu_callbacks kernel/rcu/tree.c:3182
> hardirqs last disabled at (2316923): [<     inline     >]
> __rcu_process_callbacks kernel/rcu/tree.c:3149
> hardirqs last disabled at (2316923): [<ffff20000820fe80>]
> rcu_process_callbacks+0x210/0xc28 kernel/rcu/tree.c:3166
> softirqs last  enabled at (2316912): [<ffff20000811b4c4>]
> _local_bh_enable+0x4c/0x80 kernel/softirq.c:155
> softirqs last disabled at (2316913): [<     inline     >]
> do_softirq_own_stack ./include/linux/interrupt.h:488
> softirqs last disabled at (2316913): [<     inline     >]
> invoke_softirq kernel/softirq.c:371
> softirqs last disabled at (2316913): [<ffff20000811c994>]
> irq_exit+0x264/0x308 kernel/softirq.c:405
>
> other info that might help us debug this:
>  Possible unsafe locking scenario:
>
>        CPU0
>        ----
>   lock(ucounts_lock);
>   <Interrupt>
>     lock(ucounts_lock);
>
>  *** DEADLOCK ***
>
> 1 lock held by swapper/2/0:
>  #0:  (rcu_callback){......}, at: [<     inline     >] __rcu_reclaim
> kernel/rcu/rcu.h:108
>  #0:  (rcu_callback){......}, at: [<     inline     >] rcu_do_batch
> kernel/rcu/tree.c:2919
>  #0:  (rcu_callback){......}, at: [<     inline     >]
> invoke_rcu_callbacks kernel/rcu/tree.c:3182
>  #0:  (rcu_callback){......}, at: [<     inline     >]
> __rcu_process_callbacks kernel/rcu/tree.c:3149
>  #0:  (rcu_callback){......}, at: [<ffff200008210390>]
> rcu_process_callbacks+0x720/0xc28 kernel/rcu/tree.c:3166
>
> stack backtrace:
> CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.10.0-rc3-next-20170112-xc2-dirty #6
> Hardware name: Hardkernel ODROID-C2 (DT)
> Call trace:
> [<ffff20000808fa60>] dump_backtrace+0x0/0x440 arch/arm64/kernel/traps.c:500
> [<ffff20000808fec0>] show_stack+0x20/0x30 arch/arm64/kernel/traps.c:225
> [<ffff2000088a99e0>] dump_stack+0x110/0x168
> [<ffff2000082fa2b4>] print_usage_bug.part.27+0x49c/0x4bc
> kernel/locking/lockdep.c:2387
> [<     inline     >] print_usage_bug kernel/locking/lockdep.c:2357
> [<     inline     >] valid_state kernel/locking/lockdep.c:2400
> [<     inline     >] mark_lock_irq kernel/locking/lockdep.c:2617
> [<ffff2000081c89ec>] mark_lock+0x934/0xb60 kernel/locking/lockdep.c:3065
> [<     inline     >] mark_irqflags kernel/locking/lockdep.c:2923
> [<ffff2000081c9a60>] __lock_acquire+0x640/0x3260 kernel/locking/lockdep.c:3295
> [<ffff2000081cce24>] lock_acquire+0xa4/0x138 kernel/locking/lockdep.c:3753
> [<     inline     >] __raw_spin_lock ./include/linux/spinlock_api_smp.h:144
> [<ffff200009798128>] _raw_spin_lock+0x90/0xd0 kernel/locking/spinlock.c:151
> [<     inline     >] spin_lock ./include/linux/spinlock.h:302
> [<ffff2000081678c8>] put_ucounts+0x60/0x138 kernel/ucount.c:162
> [<ffff200008168364>] dec_ucount+0xf4/0x158 kernel/ucount.c:214
> [<     inline     >] dec_pid_namespaces kernel/pid_namespace.c:89
> [<ffff200008293dc8>] delayed_free_pidns+0x40/0xe0 kernel/pid_namespace.c:156
> [<     inline     >] __rcu_reclaim kernel/rcu/rcu.h:118
> [<     inline     >] rcu_do_batch kernel/rcu/tree.c:2919
> [<     inline     >] invoke_rcu_callbacks kernel/rcu/tree.c:3182
> [<     inline     >] __rcu_process_callbacks kernel/rcu/tree.c:3149
> [<ffff2000082103d8>] rcu_process_callbacks+0x768/0xc28 kernel/rcu/tree.c:3166
> [<ffff2000080821dc>] __do_softirq+0x324/0x6e0 kernel/softirq.c:284
> [<     inline     >] do_softirq_own_stack ./include/linux/interrupt.h:488
> [<     inline     >] invoke_softirq kernel/softirq.c:371
> [<ffff20000811c994>] irq_exit+0x264/0x308 kernel/softirq.c:405
> [<ffff2000081ecc28>] __handle_domain_irq+0xc0/0x150 kernel/irq/irqdesc.c:636
> [<ffff200008081c80>] gic_handle_irq+0x68/0xd8
> Exception stack(0xffff8000648e7dd0 to 0xffff8000648e7f00)
> 7dc0:                                   ffff8000648d4b3c 0000000000000007
> 7de0: 0000000000000000 1ffff0000c91a967 1ffff0000c91a967 1ffff0000c91a967
> 7e00: ffff20000a4b6b68 0000000000000001 0000000000000007 0000000000000001
> 7e20: 1fffe4000149ae90 ffff200009d35000 0000000000000000 0000000000000002
> 7e40: 0000000000000000 0000000000000000 0000000002624a1a 0000000000000000
> 7e60: 0000000000000000 ffff200009cbcd88 000060006d2ed000 0000000000000140
> 7e80: ffff200009cff000 ffff200009cb6000 ffff200009cc2020 ffff200009d2159d
> 7ea0: 0000000000000000 ffff8000648d4380 0000000000000000 ffff8000648e7f00
> 7ec0: ffff20000820a478 ffff8000648e7f00 ffff20000820a47c 0000000010000145
> 7ee0: 0000000000000140 dfff200000000000 ffffffffffffffff ffff20000820a478
> [<ffff2000080837f8>] el1_irq+0xb8/0x130 arch/arm64/kernel/entry.S:486
> [<     inline     >] arch_local_irq_restore
> ./arch/arm64/include/asm/irqflags.h:81
> [<ffff20000820a47c>] rcu_idle_exit+0x64/0xa8 kernel/rcu/tree.c:1030
> [<     inline     >] cpuidle_idle_call kernel/sched/idle.c:200
> [<ffff2000081bcbfc>] do_idle+0x1dc/0x2d0 kernel/sched/idle.c:243
> [<ffff2000081bd1cc>] cpu_startup_entry+0x24/0x28 kernel/sched/idle.c:345
> [<ffff200008099f8c>] secondary_start_kernel+0x2cc/0x358
> arch/arm64/kernel/smp.c:276
> [<000000000279f1a4>] 0x279f1a4
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Fixes: add7c65c ("pid: fix lockdep deadlock warning due to ucount_lock")
Fixes: f333c700 ("pidns: Add a limit on the number of pid namespaces")
Cc: stable@vger.kernel.org
Link: https://www.spinics.net/lists/kernel/msg2426637.htmlSigned-off-by: Nikolay Borisov <n.borisov.lkml@gmail.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

Fixes CVE-2016-9191, proc_sys_readdir doesn't drop reference
added by grab_header when return from !dir_emit_dots path.
It can cause any path called unregister_sysctl_table will
wait forever.

The calltrace of CVE-2016-9191:

[ 5535.960522] Call Trace:
[ 5535.963265]  [<ffffffff817cdaaf>] schedule+0x3f/0xa0
[ 5535.968817]  [<ffffffff817d33fb>] schedule_timeout+0x3db/0x6f0
[ 5535.975346]  [<ffffffff817cf055>] ? wait_for_completion+0x45/0x130
[ 5535.982256]  [<ffffffff817cf0d3>] wait_for_completion+0xc3/0x130
[ 5535.988972]  [<ffffffff810d1fd0>] ? wake_up_q+0x80/0x80
[ 5535.994804]  [<ffffffff8130de64>] drop_sysctl_table+0xc4/0xe0
[ 5536.001227]  [<ffffffff8130de17>] drop_sysctl_table+0x77/0xe0
[ 5536.007648]  [<ffffffff8130decd>] unregister_sysctl_table+0x4d/0xa0
[ 5536.014654]  [<ffffffff8130deff>] unregister_sysctl_table+0x7f/0xa0
[ 5536.021657]  [<ffffffff810f57f5>] unregister_sched_domain_sysctl+0x15/0x40
[ 5536.029344]  [<ffffffff810d7704>] partition_sched_domains+0x44/0x450
[ 5536.036447]  [<ffffffff817d0761>] ? __mutex_unlock_slowpath+0x111/0x1f0
[ 5536.043844]  [<ffffffff81167684>] rebuild_sched_domains_locked+0x64/0xb0
[ 5536.051336]  [<ffffffff8116789d>] update_flag+0x11d/0x210
[ 5536.057373]  [<ffffffff817cf61f>] ? mutex_lock_nested+0x2df/0x450
[ 5536.064186]  [<ffffffff81167acb>] ? cpuset_css_offline+0x1b/0x60
[ 5536.070899]  [<ffffffff810fce3d>] ? trace_hardirqs_on+0xd/0x10
[ 5536.077420]  [<ffffffff817cf61f>] ? mutex_lock_nested+0x2df/0x450
[ 5536.084234]  [<ffffffff8115a9f5>] ? css_killed_work_fn+0x25/0x220
[ 5536.091049]  [<ffffffff81167ae5>] cpuset_css_offline+0x35/0x60
[ 5536.097571]  [<ffffffff8115aa2c>] css_killed_work_fn+0x5c/0x220
[ 5536.104207]  [<ffffffff810bc83f>] process_one_work+0x1df/0x710
[ 5536.110736]  [<ffffffff810bc7c0>] ? process_one_work+0x160/0x710
[ 5536.117461]  [<ffffffff810bce9b>] worker_thread+0x12b/0x4a0
[ 5536.123697]  [<ffffffff810bcd70>] ? process_one_work+0x710/0x710
[ 5536.130426]  [<ffffffff810c3f7e>] kthread+0xfe/0x120
[ 5536.135991]  [<ffffffff817d4baf>] ret_from_fork+0x1f/0x40
[ 5536.142041]  [<ffffffff810c3e80>] ? kthread_create_on_node+0x230/0x230

One cgroup maintainer mentioned that "cgroup is trying to offline
a cpuset css, which takes place under cgroup_mutex.  The offlining
ends up trying to drain active usages of a sysctl table which apprently
is not happening."
The real reason is that proc_sys_readdir doesn't drop reference added
by grab_header when return from !dir_emit_dots path. So this cpuset
offline path will wait here forever.

See here for details: http://www.openwall.com/lists/oss-security/2016/11/04/13

Fixes: f0c3b509 ("[readdir] convert procfs")
Cc: stable@vger.kernel.org
Reported-by: CAI Qian <caiqian@redhat.com>
Tested-by: Yang Shukui <yangshukui@huawei.com>
Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

=========================================================
[ INFO: possible irq lock inversion dependency detected ]
4.10.0-rc2-00024-g4aecec9-dirty #118 Tainted: G        W
---------------------------------------------------------
swapper/1/0 just changed the state of lock:
 (&(&sighand->siglock)->rlock){-.....}, at: [<ffffffffbd0a1bc6>] __lock_task_sighand+0xb6/0x2c0
but this lock took another, HARDIRQ-unsafe lock in the past:
 (ucounts_lock){+.+...}
and interrupts could create inverse lock ordering between them.
other info that might help us debug this:
Chain exists of:                 &(&sighand->siglock)->rlock --> &(&tty->ctrl_lock)->rlock --> ucounts_lock
 Possible interrupt unsafe locking scenario:
       CPU0                    CPU1
       ----                    ----
  lock(ucounts_lock);
                               local_irq_disable();
                               lock(&(&sighand->siglock)->rlock);
                               lock(&(&tty->ctrl_lock)->rlock);
  <Interrupt>
    lock(&(&sighand->siglock)->rlock);

 *** DEADLOCK ***

This patch removes a dependency between rlock and ucount_lock.

Fixes: f333c700 ("pidns: Add a limit on the number of pid namespaces")
Cc: stable@vger.kernel.org
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

Add MS_KERNMOUNT to the flags that are passed.
Use sget_userns and force &init_user_ns instead of calling sget so that
even if called from a weird context the internal filesystem will be
considered to be in the intial user namespace.

Luis Ressel reported that the the failure to pass MS_KERNMOUNT into
mount_pseudo broke his in development graphics driver that uses the
generic drm infrastructure.  I am not certain the deriver was bug
free in it's usage of that infrastructure but since
mount_pseudo_xattr can never be triggered by userspace it is clearer
and less error prone, and less problematic for the code to be explicit.
Reported-by: Luis Ressel <aranea@aixah.de>
Tested-by: Luis Ressel <aranea@aixah.de>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Protecting the mountpoint hashtable with namespace_sem was sufficient
until a call to umount_mnt was added to mntput_no_expire.  At which
point it became possible for multiple calls of put_mountpoint on
the same hash chain to happen on the same time.

Kristen Johansen <kjlx@templeofstupid.com> reported:
> This can cause a panic when simultaneous callers of put_mountpoint
> attempt to free the same mountpoint.  This occurs because some callers
> hold the mount_hash_lock, while others hold the namespace lock.  Some
> even hold both.
>
> In this submitter's case, the panic manifested itself as a GP fault in
> put_mountpoint() when it called hlist_del() and attempted to dereference
> a m_hash.pprev that had been poisioned by another thread.

Al Viro observed that the simple fix is to switch from using the namespace_sem
to the mount_lock to protect the mountpoint hash table.

I have taken Al's suggested patch moved put_mountpoint in pivot_root
(instead of taking mount_lock an additional time), and have replaced
new_mountpoint with get_mountpoint a function that does the hash table
lookup and addition under the mount_lock.   The introduction of get_mounptoint
ensures that only the mount_lock is needed to manipulate the mountpoint
hashtable.

d_set_mounted is modified to only set DCACHE_MOUNTED if it is not
already set.  This allows get_mountpoint to use the setting of
DCACHE_MOUNTED to ensure adding a struct mountpoint for a dentry
happens exactly once.

Cc: stable@vger.kernel.org
Fixes: ce07d891 ("mnt: Honor MNT_LOCKED when detaching mounts")
Reported-by: Krister Johansen <kjlx@templeofstupid.com>
Suggested-by: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Al Viro <viro@ZenIV.linux.org.uk>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>

Pull DAX updates from Dan Williams:
 "The completion of Jan's DAX work for 4.10.

  As I mentioned in the libnvdimm-for-4.10 pull request, these are some
  final fixes for the DAX dirty-cacheline-tracking invalidation work
  that was merged through the -mm, ext4, and xfs trees in -rc1. These
  patches were prepared prior to the merge window, but we waited for
  4.10-rc1 to have a stable merge base after all the prerequisites were
  merged.

  Quoting Jan on the overall changes in these patches:

     "So I'd like all these 6 patches to go for rc2. The first three
      patches fix invalidation of exceptional DAX entries (a bug which
      is there for a long time) - without these patches data loss can
      occur on power failure even though user called fsync(2). The other
      three patches change locking of DAX faults so that ->iomap_begin()
      is called in a more relaxed locking context and we are safe to
      start a transaction there for ext4"

  These have received a build success notification from the kbuild
  robot, and pass the latest libnvdimm unit tests. There have not been
  any -next releases since -rc1, so they have not appeared there"

* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
  ext4: Simplify DAX fault path
  dax: Call ->iomap_begin without entry lock during dax fault
  dax: Finish fault completely when loading holes
  dax: Avoid page invalidation races and unnecessary radix tree traversals
  mm: Invalidate DAX radix tree entries only if appropriate
  ext2: Return BH_New buffers for zeroed blocks

Pull documentation fixes from Jonathan Corbet:
 "Two small fixes:

   - A merge error on my part broke the DocBook build. I've
     requisitioned one of tglx's frozen sharks for appropriate
     disciplinary action and resolved to be more careful about testing
     the DocBook stuff as long as it's still around.

   - Fix an error in unaligned-memory-access.txt"

* tag 'docs-4.10-rc1-fix' of git://git.lwn.net/linux:
  Documentation/unaligned-memory-access.txt: fix incorrect comparison operator
  docs: Fix build failure

Pull crypto fix from Herbert Xu:
 "This fixes a boot failure on some platforms when crypto self test is
  enabled along with the new acomp interface"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: testmgr - Use heap buffer for acomp test input

 mm/filemap.c: In function 'clear_bit_unlock_is_negative_byte':
  mm/filemap.c:933:9: error: too few arguments to function 'test_bit'
    return test_bit(PG_waiters);
         ^~~~~~~~

Fixes: b91e1302 ('mm: optimize PageWaiters bit use for unlock_page()')
Signed-off-by: Olof Johansson <olof@lixom.net>
Brown-paper-bag-by: Linus Torvalds <dummy@duh.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In commit 62906027 ("mm: add PageWaiters indicating tasks are
waiting for a page bit") Nick Piggin made our page locking no longer
unconditionally touch the hashed page waitqueue, which not only helps
performance in general, but is particularly helpful on NUMA machines
where the hashed wait queues can bounce around a lot.

However, the "clear lock bit atomically and then test the waiters bit"
sequence turns out to be much more expensive than it needs to be,
because you get a nasty stall when trying to access the same word that
just got updated atomically.

On architectures where locking is done with LL/SC, this would be trivial
to fix with a new primitive that clears one bit and tests another
atomically, but that ends up not working on x86, where the only atomic
operations that return the result end up being cmpxchg and xadd.  The
atomic bit operations return the old value of the same bit we changed,
not the value of an unrelated bit.

On x86, we could put the lock bit in the high bit of the byte, and use
"xadd" with that bit (where the overflow ends up not touching other
bits), and look at the other bits of the result.  However, an even
simpler model is to just use a regular atomic "and" to clear the lock
bit, and then the sign bit in eflags will indicate the resulting state
of the unrelated bit #7.

So by moving the PageWaiters bit up to bit #7, we can atomically clear
the lock bit and test the waiters bit on x86 too.  And architectures
with LL/SC (which is all the usual RISC suspects), the particular bit
doesn't matter, so they are fine with this approach too.

This avoids the extra access to the same atomic word, and thus avoids
the costly stall at page unlock time.

The only downside is that the interface ends up being a bit odd and
specialized: clear a bit in a byte, and test the sign bit.  Nick doesn't
love the resulting name of the new primitive, but I'd rather make the
name be descriptive and very clear about the limitation imposed by
trying to work across all relevant architectures than make it be some
generic thing that doesn't make the odd semantics explicit.

So this introduces the new architecture primitive

    clear_bit_unlock_is_negative_byte();

and adds the trivial implementation for x86.  We have a generic
non-optimized fallback (that just does a "clear_bit()"+"test_bit(7)"
combination) which can be overridden by any architecture that can do
better.  According to Nick, Power has the same hickup x86 has, for
example, but some other architectures may not even care.

All these optimizations mean that my page locking stress-test (which is
just executing a lot of small short-lived shell scripts: "make test" in
the git source tree) no longer makes our page locking look horribly bad.
Before all these optimizations, just the unlock_page() costs were just
over 3% of all CPU overhead on "make test".  After this, it's down to
0.66%, so just a quarter of the cost it used to be.

(The difference on NUMA is bigger, but there this micro-optimization is
likely less noticeable, since the big issue on NUMA was not the accesses
to 'struct page', but the waitqueue accesses that were already removed
by Nick's earlier commit).
Acked-by: Nick Piggin <npiggin@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Andrew Lutomirski <luto@kernel.org>
Cc: Andreas Gruenbacher <agruenba@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull crypto fix from Herbert Xu:
 "This fixes a hash corruption bug in the marvell driver"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: marvell - Copy IVDIG before launching partial DMA ahash requests

Pull networking fixes from David Miller:

 1) Various ipvlan fixes from Eric Dumazet and Mahesh Bandewar.

    The most important is to not assume the packet is RX just because
    the destination address matches that of the device. Such an
    assumption causes problems when an interface is put into loopback
    mode.

 2) If we retry when creating a new tc entry (because we dropped the
    RTNL mutex in order to load a module, for example) we end up with
    -EAGAIN and then loop trying to replay the request. But we didn't
    reset some state when looping back to the top like this, and if
    another thread meanwhile inserted the same tc entry we were trying
    to, we re-link it creating an enless loop in the tc chain. Fix from
    Daniel Borkmann.

 3) There are two different WRITE bits in the MDIO address register for
    the stmmac chip, depending upon the chip variant. Due to a bug we
    could set them both, fix from Hock Leong Kweh.

 4) Fix mlx4 bug in XDP_TX handling, from Tariq Toukan.

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net:
  net: stmmac: fix incorrect bit set in gmac4 mdio addr register
  r8169: add support for RTL8168 series add-on card.
  net: xdp: remove unused bfp_warn_invalid_xdp_buffer()
  openvswitch: upcall: Fix vlan handling.
  ipv4: Namespaceify tcp_tw_reuse knob
  net: korina: Fix NAPI versus resources freeing
  net, sched: fix soft lockup in tc_classify
  net/mlx4_en: Fix user prio field in XDP forward
  tipc: don't send FIN message from connectionless socket
  ipvlan: fix multicast processing
  ipvlan: fix various issues in ipvlan_process_multicast()

In the actual implementation ether_addr_equal function tests for equality to 0
when returning. It seems in commit 0d74c4 it is somehow overlooked to change
this operator to reflect the actual function.
Signed-off-by: Cihangir Akturk <cakturk@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The 80211.tmpl DocBook file was removed in commit 819bf593 ("docs-rst:
sphinxify 802.11 documentation"), but the 80211.xml target was re-added to
the Makefile by commit 7ddedebb ("ALSA: doc: ReSTize
writing-an-alsa-driver document"), leading to a failure when building the
documentation:

*** No rule to make target 'Documentation/DocBook/80211.xml', needed by
'Documentation/DocBook/80211.aux.xml'.

cc: stable@vger.kernel.org
Signed-off-by: John Brooks <john@fastquake.com>
Mea-culpa-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Linux 4.10-rc1

Fixing the gmac4 mdio write access to use MII_GMAC4_WRITE only instead of
OR together with MII_WRITE.
Signed-off-by: Kweh, Hock Leong <hock.leong.kweh@intel.com>
Acked-By: Joao Pinto <jpinto@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This chip is the same as RTL8168, but its device id is 0x8161.
Signed-off-by: Chun-Hao Lin <hau@realtek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

After commit 73b62bd0 ("virtio-net:
remove the warning before XDP linearizing"), there's no users for
bpf_warn_invalid_xdp_buffer(), so remove it. This is a revert for
commit f23bc46c.

Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

Networking stack accelerate vlan tag handling by
keeping topmost vlan header in skb. This works as
long as packet remains in OVS datapath. But during
OVS upcall vlan header is pushed on to the packet.
When such packet is sent back to OVS datapath, core
networking stack might not handle it correctly. Following
patch avoids this issue by accelerating the vlan tag
during flow key extract. This simplifies datapath by
bringing uniform packet processing for packets from
all code paths.

Fixes: 5108bbad ("openvswitch: add processing of L3 packets").
CC: Jarno Rajahalme <jarno@ovn.org>
CC: Jiri Benc <jbenc@redhat.com>
Signed-off-by: Pravin B Shelar <pshelar@ovn.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Different namespaces might have different requirements to reuse
TIME-WAIT sockets for new connections. This might be required in
cases where different namespace applications are in place which
require TIME_WAIT socket connections to be reduced independently
of the host.
Signed-off-by: Haishuang Yan <yanhaishuang@cmss.chinamobile.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Christopher Covington reported a crash on aarch64 on recent Fedora
kernels:

kernel BUG at ./include/linux/scatterlist.h:140!
Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
Modules linked in:
CPU: 2 PID: 752 Comm: cryptomgr_test Not tainted 4.9.0-11815-ge93b1cc8 #162
Hardware name: linux,dummy-virt (DT)
task: ffff80007c650080 task.stack: ffff800008910000
PC is at sg_init_one+0xa0/0xb8
LR is at sg_init_one+0x24/0xb8
...
[<ffff000008398db8>] sg_init_one+0xa0/0xb8
[<ffff000008350a44>] test_acomp+0x10c/0x438
[<ffff000008350e20>] alg_test_comp+0xb0/0x118
[<ffff00000834f28c>] alg_test+0x17c/0x2f0
[<ffff00000834c6a4>] cryptomgr_test+0x44/0x50
[<ffff0000080dac70>] kthread+0xf8/0x128
[<ffff000008082ec0>] ret_from_fork+0x10/0x50

The test vectors used for input are part of the kernel image. These
inputs are passed as a buffer to sg_init_one which eventually blows up
with BUG_ON(!virt_addr_valid(buf)). On arm64, virt_addr_valid returns
false for the kernel image since virt_to_page will not return the
correct page. Fix this by copying the input vectors to heap buffer
before setting up the scatterlist.
Reported-by: Christopher Covington <cov@codeaurora.org>
Fixes: d7db7a88 ("crypto: acomp - update testmgr with support for acomp")
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Now that dax_iomap_fault() calls ->iomap_begin() without entry lock, we
can use transaction starting in ext4_iomap_begin() and thus simplify
ext4_dax_fault(). It also provides us proper retries in case of ENOSPC.
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Currently ->iomap_begin() handler is called with entry lock held. If the
filesystem held any locks between ->iomap_begin() and ->iomap_end()
(such as ext4 which will want to hold transaction open), this would cause
lock inversion with the iomap_apply() from standard IO path which first
calls ->iomap_begin() and only then calls ->actor() callback which grabs
entry locks for DAX (if it faults when copying from/to user provided
buffers).

Fix the problem by nesting grabbing of entry lock inside ->iomap_begin()
- ->iomap_end() pair.
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

The only case when we do not finish the page fault completely is when we
are loading hole pages into a radix tree. Avoid this special case and
finish the fault in that case as well inside the DAX fault handler. It
will allow us for easier iomap handling.
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Currently dax_iomap_rw() takes care of invalidating page tables and
evicting hole pages from the radix tree when write(2) to the file
happens. This invalidation is only necessary when there is some block
allocation resulting from write(2). Furthermore in current place the
invalidation is racy wrt page fault instantiating a hole page just after
we have invalidated it.

So perform the page invalidation inside dax_iomap_actor() where we can
do it only when really necessary and after blocks have been allocated so
nobody will be instantiating new hole pages anymore.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Currently invalidate_inode_pages2_range() and invalidate_mapping_pages()
just delete all exceptional radix tree entries they find. For DAX this
is not desirable as we track cache dirtiness in these entries and when
they are evicted, we may not flush caches although it is necessary. This
can for example manifest when we write to the same block both via mmap
and via write(2) (to different offsets) and fsync(2) then does not
properly flush CPU caches when modification via write(2) was the last
one.

Create appropriate DAX functions to handle invalidation of DAX entries
for invalidate_inode_pages2_range() and invalidate_mapping_pages() and
wire them up into the corresponding mm functions.
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

So far we did not return BH_New buffers from ext2_get_blocks() when we
allocated and zeroed-out a block for DAX inode to avoid racy zeroing in
DAX code. This zeroing is gone these days so we can remove the
workaround.
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

If mce_device_init() fails then the mce device pointer is NULL and the
AMD mce code happily dereferences it.

Add a sanity check.
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The attempt to prevent overwriting an active state resulted in a
disaster which effectively disables all dynamically allocated hotplug
states.

Cleanup the mess.

Fixes: dc280d93 ("cpu/hotplug: Prevent overwriting of callbacks")
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Split asm-only parts of arm64 uaccess.h into a new header and use that
from *.S.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

Commit beb0babf ("korina: disable napi on close and restart")
introduced calls to napi_disable() that were missing before,
unfortunately this leaves a small window during which NAPI has a chance
to run, yet we just freed resources since korina_free_ring() has been
called:

Fix this by disabling NAPI first then freeing resource, and make sure
that we also cancel the restart task before doing the resource freeing.

Fixes: beb0babf ("korina: disable napi on close and restart")
Reported-by: Alexandros C. Couloumbis <alex@ozo.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Shahar reported a soft lockup in tc_classify(), where we run into an
endless loop when walking the classifier chain due to tp->next == tp
which is a state we should never run into. The issue only seems to
trigger under load in the tc control path.

What happens is that in tc_ctl_tfilter(), thread A allocates a new
tp, initializes it, sets tp_created to 1, and calls into tp->ops->change()
with it. In that classifier callback we had to unlock/lock the rtnl
mutex and returned with -EAGAIN. One reason why we need to drop there
is, for example, that we need to request an action module to be loaded.

This happens via tcf_exts_validate() -> tcf_action_init/_1() meaning
after we loaded and found the requested action, we need to redo the
whole request so we don't race against others. While we had to unlock
rtnl in that time, thread B's request was processed next on that CPU.
Thread B added a new tp instance successfully to the classifier chain.
When thread A returned grabbing the rtnl mutex again, propagating -EAGAIN
and destroying its tp instance which never got linked, we goto replay
and redo A's request.

This time when walking the classifier chain in tc_ctl_tfilter() for
checking for existing tp instances we had a priority match and found
the tp instance that was created and linked by thread B. Now calling
again into tp->ops->change() with that tp was successful and returned
without error.

tp_created was never cleared in the second round, thus kernel thinks
that we need to link it into the classifier chain (once again). tp and
*back point to the same object due to the match we had earlier on. Thus
for thread B's already public tp, we reset tp->next to tp itself and
link it into the chain, which eventually causes the mentioned endless
loop in tc_classify() once a packet hits the data path.

Fix is to clear tp_created at the beginning of each request, also when
we replay it. On the paths that can cause -EAGAIN we already destroy
the original tp instance we had and on replay we really need to start
from scratch. It seems that this issue was first introduced in commit
12186be7 ("net_cls: fix unconfigured struct tcf_proto keeps chaining
and avoid kernel panic when we use cls_cgroup").

Fixes: 12186be7 ("net_cls: fix unconfigured struct tcf_proto keeps chaining and avoid kernel panic when we use cls_cgroup")
Reported-by: Shahar Klein <shahark@mellanox.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Tested-by: Shahar Klein <shahark@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

I am getting the following warning when I build kernel 4.9-git on my
PowerBook G4 with a 32-bit PPC processor:

    AS      arch/powerpc/kernel/misc_32.o
  arch/powerpc/kernel/misc_32.S:299:7: warning: "CONFIG_FSL_BOOKE" is not defined [-Wundef]

This problem is evident after commit 989cea5c ("kbuild: prevent
lib-ksyms.o rebuilds"); however, this change in kbuild only exposes an
error that has been in the code since 2005 when this source file was
created.  That was with commit 9994a338 ("powerpc: Introduce
entry_{32,64}.S, misc_{32,64}.S, systbl.S").

The offending line does not make a lot of sense.  This error does not
seem to cause any errors in the executable, thus I am not recommending
that it be applied to any stable versions.

Thanks to Nicholas Piggin for suggesting this solution.

Fixes: 9994a338 ("powerpc: Introduce entry_{32,64}.S, misc_{32,64}.S, systbl.S")
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>