We have a MAX_LFS_FILESIZE macro that is meant to be filled in by
filesystems (and other IO targets) that know they are 64-bit clean and
don't have any 32-bit limits in their IO path.

It turns out that our 32-bit value for that limit was bogus.  On 32-bit,
the VM layer is limited by the page cache to only 32-bit index values,
but our logic for that was confusing and actually wrong.  We used to
define that value to

	(((loff_t)PAGE_SIZE << (BITS_PER_LONG-1))-1)

which is actually odd in several ways: it limits the index to 31 bits,
and then it limits files so that they can't have data in that last byte
of a page that has the highest 31-bit index (ie page index 0x7fffffff).

Neither of those limitations make sense.  The index is actually the full
32 bit unsigned value, and we can use that whole full page.  So the
maximum size of the file would logically be "PAGE_SIZE << BITS_PER_LONG".

However, we do wan tto avoid the maximum index, because we have code
that iterates over the page indexes, and we don't want that code to
overflow.  So the maximum size of a file on a 32-bit host should
actually be one page less than the full 32-bit index.

So the actual limit is ULONG_MAX << PAGE_SHIFT.  That means that we will
not actually be using the page of that last index (ULONG_MAX), but we
can grow a file up to that limit.

The wrong value of MAX_LFS_FILESIZE actually caused problems for Doug
Nazar, who was still using a 32-bit host, but with a 9.7TB 2 x RAID5
volume.  It turns out that our old MAX_LFS_FILESIZE was 8TiB (well, one
byte less), but the actual true VM limit is one page less than 16TiB.

This was invisible until commit c2a9737f ("vfs,mm: fix a dead loop
in truncate_inode_pages_range()"), which started applying that
MAX_LFS_FILESIZE limit to block devices too.

NOTE! On 64-bit, the page index isn't a limiter at all, and the limit is
actually just the offset type itself (loff_t), which is signed.  But for
clarity, on 64-bit, just use the maximum signed value, and don't make
people have to count the number of 'f' characters in the hex constant.

So just use LLONG_MAX for the 64-bit case.  That was what the value had
been before too, just written out as a hex constant.

Fixes: c2a9737f ("vfs,mm: fix a dead loop in truncate_inode_pages_range()")
Reported-and-tested-by: NDoug Nazar <nazard@nazar.ca>
Cc: Andreas Dilger <adilger@dilger.ca>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Dave Kleikamp <shaggy@kernel.org>
Cc: stable@kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The implementation of TIOCGPTPEER has two issues.

When /dev/ptmx (as opposed to /dev/pts/ptmx) is opened the wrong
vfsmount is passed to dentry_open.  Which results in the kernel displaying
the wrong pathname for the peer.

The second is simply by caching the vfsmount and dentry of the peer it leaves
them open, in a way they were not previously Which because of the inreased
reference counts can cause unnecessary behaviour differences resulting in
regressions.

To fix these move the ioctl into tty_io.c at a generic level allowing
the ioctl to have access to the struct file on which the ioctl is
being called.  This allows the path of the slave to be derived when
opening the slave through TIOCGPTPEER instead of requiring the path to
the slave be cached.  Thus removing the need for caching the path.

A new function devpts_ptmx_path is factored out of devpts_acquire and
used to implement a function devpts_mntget.   The new function devpts_mntget
takes a filp to perform the lookup on and fsi so that it can confirm
that the superblock that is found by devpts_ptmx_path is the proper superblock.

v2: Lots of fixes to make the code actually work
v3: Suggestions by Linus
    - Removed the unnecessary initialization of filp in ptm_open_peer
    - Simplified devpts_ptmx_path as gotos are no longer required

[ This is the fix for the issue that was reverted in commit
  143c97cc, but this time without breaking 'pbuilder' due to
  increased reference counts   - Linus ]

Fixes: 54ebbfb1 ("tty: add TIOCGPTPEER ioctl")
Reported-by: NChristian Brauner <christian.brauner@canonical.com>
Reported-and-tested-by: NStefan Lippers-Hollmann <s.l-h@gmx.de>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 44c58487 ("IB/core: Define 'ib' and 'roce' rdma_ah_attr types")
introduced the concept of type in ah_attr:
 * During ib_register_device, each port is checked for its type which
   is stored in ib_device's port_immutable array.
 * During uverbs' modify_qp, the type is inferred using the port number
   in ib_uverbs_qp_dest struct (address vector) by accessing the
   relevant port_immutable array and the type is passed on to
   providers.

IB spec (version 1.3) enforces a valid port value only in Reset to
Init. During Init to RTR, the address vector must be valid but port
number is not mentioned as a field in the address vector, so its
value is not validated, which leads to accesses to a non-allocated
memory when inferring the port type.

Save the real port number in ib_qp during modify to Init (when the
comp_mask indicates that the port number is valid) and use this value
to infer the port type.

Avoid copying the address vector fields if the matching bit is not set
in the attr_mask. Address vector can't be modified before the port, so
no valid flow is affected.

Fixes: 44c58487 ('IB/core: Define 'ib' and 'roce' rdma_ah_attr types')
Signed-off-by: NNoa Osherovich <noaos@mellanox.com>
Reviewed-by: NYishai Hadas <yishaih@mellanox.com>
Signed-off-by: NLeon Romanovsky <leon@kernel.org>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Since we split the scsi_request out of struct request bsg fails to
provide a reply-buffer for the drivers. This was done via the pointer
for sense-data, that is not preallocated anymore.

Failing to allocate/assign it results in illegal dereferences because
LLDs use this pointer unquestioned.

An example panic on s390x, using the zFCP driver, looks like this (I had
debugging on, otherwise NULL-pointer dereferences wouldn't even panic on
s390x):

Unable to handle kernel pointer dereference in virtual kernel address space
Failing address: 6b6b6b6b6b6b6000 TEID: 6b6b6b6b6b6b6403
Fault in home space mode while using kernel ASCE.
AS:0000000001590007 R3:0000000000000024
Oops: 0038 ilc:2 [#1] PREEMPT SMP DEBUG_PAGEALLOC
Modules linked in: <Long List>
CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.12.0-bsg-regression+ #3
Hardware name: IBM 2964 N96 702 (z/VM 6.4.0)
task: 0000000065cb0100 task.stack: 0000000065cb4000
Krnl PSW : 0704e00180000000 000003ff801e4156 (zfcp_fc_ct_els_job_handler+0x16/0x58 [zfcp])
           R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
Krnl GPRS: 0000000000000001 000000005fa9d0d0 000000005fa9d078 0000000000e16866
           000003ff00000290 6b6b6b6b6b6b6b6b 0000000059f78f00 000000000000000f
           00000000593a0958 00000000593a0958 0000000060d88800 000000005ddd4c38
           0000000058b50100 07000000659cba08 000003ff801e8556 00000000659cb9a8
Krnl Code: 000003ff801e4146: e31020500004        lg      %r1,80(%r2)
           000003ff801e414c: 58402040           l       %r4,64(%r2)
          #000003ff801e4150: e35020200004       lg      %r5,32(%r2)
          >000003ff801e4156: 50405004           st      %r4,4(%r5)
           000003ff801e415a: e54c50080000       mvhi    8(%r5),0
           000003ff801e4160: e33010280012       lt      %r3,40(%r1)
           000003ff801e4166: a718fffb           lhi     %r1,-5
           000003ff801e416a: 1803               lr      %r0,%r3
Call Trace:
([<000003ff801e8556>] zfcp_fsf_req_complete+0x726/0x768 [zfcp])
 [<000003ff801ea82a>] zfcp_fsf_reqid_check+0x102/0x180 [zfcp]
 [<000003ff801eb980>] zfcp_qdio_int_resp+0x230/0x278 [zfcp]
 [<00000000009b91b6>] qdio_kick_handler+0x2ae/0x2c8
 [<00000000009b9e3e>] __tiqdio_inbound_processing+0x406/0xc10
 [<00000000001684c2>] tasklet_action+0x15a/0x1d8
 [<0000000000bd28ec>] __do_softirq+0x3ec/0x848
 [<00000000001675a4>] irq_exit+0x74/0xf8
 [<000000000010dd6a>] do_IRQ+0xba/0xf0
 [<0000000000bd19e8>] io_int_handler+0x104/0x2d4
 [<00000000001033b6>] enabled_wait+0xb6/0x188
([<000000000010339e>] enabled_wait+0x9e/0x188)
 [<000000000010396a>] arch_cpu_idle+0x32/0x50
 [<0000000000bd0112>] default_idle_call+0x52/0x68
 [<00000000001cd0fa>] do_idle+0x102/0x188
 [<00000000001cd41e>] cpu_startup_entry+0x3e/0x48
 [<0000000000118c64>] smp_start_secondary+0x11c/0x130
 [<0000000000bd2016>] restart_int_handler+0x62/0x78
 [<0000000000000000>]           (null)
INFO: lockdep is turned off.
Last Breaking-Event-Address:
 [<000003ff801e41d6>] zfcp_fc_ct_job_handler+0x3e/0x48 [zfcp]

Kernel panic - not syncing: Fatal exception in interrupt

This patch moves bsg-lib to allocate and setup struct bsg_job ahead of
time, including the allocation of a buffer for the reply-data.

This means, struct bsg_job is not allocated separately anymore, but as part
of struct request allocation - similar to struct scsi_cmd. Reflect this in
the function names that used to handle creation/destruction of struct
bsg_job.
Reported-by: NSteffen Maier <maier@linux.vnet.ibm.com>
Suggested-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NBenjamin Block <bblock@linux.vnet.ibm.com>
Fixes: 82ed4db4 ("block: split scsi_request out of struct request")
Cc: <stable@vger.kernel.org> #4.11+
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This reverts commit c8c03f18.

It turns out that while fixing the ptmx file descriptor to have the
correct 'struct path' to the associated slave pty is a really good
thing, it breaks some user space tools for a very annoying reason.

The problem is that /dev/ptmx and its associated slave pty (/dev/pts/X)
are on different mounts.  That was what caused us to have the wrong path
in the first place (we would mix up the vfsmount of the 'ptmx' node,
with the dentry of the pty slave node), but it also means that now while
we use the right vfsmount, having the pty master open also keeps the pts
mount busy.

And it turn sout that that makes 'pbuilder' very unhappy, as noted by
Stefan Lippers-Hollmann:

 "This patch introduces a regression for me when using pbuilder
  0.228.7[2] (a helper to build Debian packages in a chroot and to
  create and update its chroots) when trying to umount /dev/ptmx (inside
  the chroot) on Debian/ unstable (full log and pbuilder configuration
  file[3] attached).

  [...]
  Setting up build-essential (12.3) ...
  Processing triggers for libc-bin (2.24-15) ...
  I: unmounting dev/ptmx filesystem
  W: Could not unmount dev/ptmx: umount: /var/cache/pbuilder/build/1340/dev/ptmx: target is busy
          (In some cases useful info about processes that
           use the device is found by lsof(8) or fuser(1).)"

apparently pbuilder tries to unmount the /dev/pts filesystem while still
holding at least one master node open, which is arguably not very nice,
but we don't break user space even when fixing other bugs.

So this commit has to be reverted.

I'll try to figure out a way to avoid caching the path to the slave pty
in the master pty.  The only thing that actually wants that slave pty
path is the "TIOCGPTPEER" ioctl, and I think we could just recreate the
path at that time.
Reported-by: NStefan Lippers-Hollmann <s.l-h@gmx.de>
Cc: Eric W Biederman <ebiederm@xmission.com>
Cc: Christian Brauner <christian.brauner@canonical.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There's some stuff still up in the air, let's not get stuck with a
subpar ABI. I'll follow up with something better for 4.14.
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

This was reported many times, and this was even mentioned in commit
52ee2dfd ("pids: refactor vnr/nr_ns helpers to make them safe") but
somehow nobody bothered to fix the obvious problem: task_tgid_nr_ns() is
not safe because task->group_leader points to nowhere after the exiting
task passes exit_notify(), rcu_read_lock() can not help.

We really need to change __unhash_process() to nullify group_leader,
parent, and real_parent, but this needs some cleanups.  Until then we
can turn task_tgid_nr_ns() into another user of __task_pid_nr_ns() and
fix the problem.
Reported-by: NTroy Kensinger <tkensinger@google.com>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This important to call qdisc_tree_reduce_backlog() after changing queue
length. Parent qdisc should deactivate class in ->qlen_notify() called from
qdisc_tree_reduce_backlog() but this happens only if qdisc->q.qlen in zero.

Missed class deactivations leads to crashes/warnings at picking packets
from empty qdisc and corrupting state at reactivating this class in future.
Signed-off-by: NKonstantin Khlebnikov <khlebnikov@yandex-team.ru>
Fixes: 86a7996c ("net_sched: introduce qdisc_replace() helper")
Acked-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The kerneldoc description for the trig_readonly field of struct iio_dev
lacked a colon, leading to this doc build warning:

  ./include/linux/iio/iio.h:603: warning: No description found for parameter 'trig_readonly'

A similar issue for iio_trigger_set_immutable() in trigger.h yielded:

  ./include/linux/iio/trigger.h:151: warning: No description found for parameter 'indio_dev'
  ./include/linux/iio/trigger.h:151: warning: No description found for parameter 'trig'

Fix the formatting and silence the warnings.
Signed-off-by: NJonathan Corbet <corbet@lwn.net>
Signed-off-by: NJonathan Cameron <Jonathan.Cameron@huawei.com>

Wenwei Tao has noticed that our current assumption that the oom victim
is dying and never doing any visible changes after it dies, and so the
oom_reaper can tear it down, is not entirely true.

__task_will_free_mem consider a task dying when SIGNAL_GROUP_EXIT is set
but do_group_exit sends SIGKILL to all threads _after_ the flag is set.
So there is a race window when some threads won't have
fatal_signal_pending while the oom_reaper could start unmapping the
address space.  Moreover some paths might not check for fatal signals
before each PF/g-u-p/copy_from_user.

We already have a protection for oom_reaper vs.  PF races by checking
MMF_UNSTABLE.  This has been, however, checked only for kernel threads
(use_mm users) which can outlive the oom victim.  A simple fix would be
to extend the current check in handle_mm_fault for all tasks but that
wouldn't be sufficient because the current check assumes that a kernel
thread would bail out after EFAULT from get_user*/copy_from_user and
never re-read the same address which would succeed because the PF path
has established page tables already.  This seems to be the case for the
only existing use_mm user currently (virtio driver) but it is rather
fragile in general.

This is even more fragile in general for more complex paths such as
generic_perform_write which can re-read the same address more times
(e.g.  iov_iter_copy_from_user_atomic to fail and then
iov_iter_fault_in_readable on retry).

Therefore we have to implement MMF_UNSTABLE protection in a robust way
and never make a potentially corrupted content visible.  That requires
to hook deeper into the PF path and check for the flag _every time_
before a pte for anonymous memory is established (that means all
!VM_SHARED mappings).

The corruption can be triggered artificially
(http://lkml.kernel.org/r/201708040646.v746kkhC024636@www262.sakura.ne.jp)
but there doesn't seem to be any real life bug report.  The race window
should be quite tight to trigger most of the time.

Link: http://lkml.kernel.org/r/20170807113839.16695-3-mhocko@kernel.org
Fixes: aac45363 ("mm, oom: introduce oom reaper")
Signed-off-by: NMichal Hocko <mhocko@suse.com>
Reported-by: NWenwei Tao <wenwei.tww@alibaba-inc.com>
Tested-by: NTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Andrea Argangeli <andrea@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is existing use after free bug when deferred struct pages are
enabled:

The memblock_add() allocates memory for the memory array if more than
128 entries are needed.  See comment in e820__memblock_setup():

  * The bootstrap memblock region count maximum is 128 entries
  * (INIT_MEMBLOCK_REGIONS), but EFI might pass us more E820 entries
  * than that - so allow memblock resizing.

This memblock memory is freed here:
        free_low_memory_core_early()

We access the freed memblock.memory later in boot when deferred pages
are initialized in this path:

        deferred_init_memmap()
                for_each_mem_pfn_range()
                  __next_mem_pfn_range()
                    type = &memblock.memory;

One possible explanation for why this use-after-free hasn't been hit
before is that the limit of INIT_MEMBLOCK_REGIONS has never been
exceeded at least on systems where deferred struct pages were enabled.

Tested by reducing INIT_MEMBLOCK_REGIONS down to 4 from the current 128,
and verifying in qemu that this code is getting excuted and that the
freed pages are sane.

Link: http://lkml.kernel.org/r/1502485554-318703-2-git-send-email-pasha.tatashin@oracle.com
Fixes: 7e18adb4 ("mm: meminit: initialise remaining struct pages in parallel with kswapd")
Signed-off-by: NPavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: NSteven Sistare <steven.sistare@oracle.com>
Reviewed-by: NDaniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: NBob Picco <bob.picco@oracle.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

These are the few pending fixes I have queued up for v4.13-final.  One
is a a generic regression fix for recursive loops on kmod and the other
one is a trivial print out correction.

During the v4.13 development we assumed that recursive kmod loops were
no longer possible.  Clearly that is not true.  The regression fix makes
use of a new killable wait.  We use a killable wait to be paranoid in
how signals might be sent to modprobe and only accept a proper SIGKILL.
The signal will only be available to userspace to issue *iff* a thread
has already entered a wait state, and that happens only if we've already
throttled after 50 kmod threads have been hit.

Note that although it may seem excessive to trigger a failure afer 5
seconds if all kmod thread remain busy, prior to the series of changes
that went into v4.13 we would actually *always* fatally fail any request
which came in if the limit was already reached.  The new waiting
implemented in v4.13 actually gives us *more* breathing room -- the wait
for 5 seconds is a wait for *any* kmod thread to finish.  We give up and
fail *iff* no kmod thread has finished and they're *all* running
straight for 5 consecutive seconds.  If 50 kmod threads are running
consecutively for 5 seconds something else must be really bad.

Recursive loops with kmod are bad but they're also hard to implement
properly as a selftest without currently fooling current userspace tools
like kmod [1].  For instance kmod will complain when you run depmod if
it finds a recursive loop with symbol dependency between modules as such
this type of recursive loop cannot go upstream as the modules_install
target will fail after running depmod.

These tests already exist on userspace kmod upstream though (refer to
the testsuite/module-playground/mod-loop-*.c files).  The same is not
true if request_module() is used though, or worst if aliases are used.

Likewise the issue with 64-bit kernels booting 32-bit userspace without
a binfmt handler built-in is also currently not detected and proactively
avoided by userspace kmod tools, or kconfig for all architectures.
Although we could complain in the kernel when some of these individual
recursive issues creep up, proactively avoiding these situations in
userspace at build time is what we should keep striving for.

Lastly, since recursive loops could happen with kmod it may mean
recursive loops may also be possible with other kernel usermode helpers,
this should be investigated and long term if we can come up with a more
sensible generic solution even better!

[0] https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux.git/log/?h=20170809-kmod-for-v4.13-final
[1] https://git.kernel.org/pub/scm/utils/kernel/kmod/kmod.git

This patch (of 3):

This wait is similar to wait_event_interruptible_timeout() but only
accepts SIGKILL interrupt signal.  Other signals are ignored.

Link: http://lkml.kernel.org/r/20170809234635.13443-2-mcgrof@kernel.orgSigned-off-by: NLuis R. Rodriguez <mcgrof@kernel.org>
Acked-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: Jessica Yu <jeyu@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Michal Marek <mmarek@suse.com>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Miroslav Benes <mbenes@suse.cz>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Matt Redfearn <matt.redfearn@imgtec.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Daniel Mentz <danielmentz@google.com>
Cc: David Binderman <dcb314@hotmail.com>
Cc: Matt Redfearn <matt.redfearn@imgetc.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Jaegeuk and Brad report a NULL pointer crash when writeback ending tries
to update the memcg stats:

    BUG: unable to handle kernel NULL pointer dereference at 00000000000003b0
    IP: test_clear_page_writeback+0x12e/0x2c0
    [...]
    RIP: 0010:test_clear_page_writeback+0x12e/0x2c0
    Call Trace:
     <IRQ>
     end_page_writeback+0x47/0x70
     f2fs_write_end_io+0x76/0x180 [f2fs]
     bio_endio+0x9f/0x120
     blk_update_request+0xa8/0x2f0
     scsi_end_request+0x39/0x1d0
     scsi_io_completion+0x211/0x690
     scsi_finish_command+0xd9/0x120
     scsi_softirq_done+0x127/0x150
     __blk_mq_complete_request_remote+0x13/0x20
     flush_smp_call_function_queue+0x56/0x110
     generic_smp_call_function_single_interrupt+0x13/0x30
     smp_call_function_single_interrupt+0x27/0x40
     call_function_single_interrupt+0x89/0x90
    RIP: 0010:native_safe_halt+0x6/0x10

    (gdb) l *(test_clear_page_writeback+0x12e)
    0xffffffff811bae3e is in test_clear_page_writeback (./include/linux/memcontrol.h:619).
    614		mod_node_page_state(page_pgdat(page), idx, val);
    615		if (mem_cgroup_disabled() || !page->mem_cgroup)
    616			return;
    617		mod_memcg_state(page->mem_cgroup, idx, val);
    618		pn = page->mem_cgroup->nodeinfo[page_to_nid(page)];
    619		this_cpu_add(pn->lruvec_stat->count[idx], val);
    620	}
    621
    622	unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
    623							gfp_t gfp_mask,

The issue is that writeback doesn't hold a page reference and the page
might get freed after PG_writeback is cleared (and the mapping is
unlocked) in test_clear_page_writeback().  The stat functions looking up
the page's node or zone are safe, as those attributes are static across
allocation and free cycles.  But page->mem_cgroup is not, and it will
get cleared if we race with truncation or migration.

It appears this race window has been around for a while, but less likely
to trigger when the memcg stats were updated first thing after
PG_writeback is cleared.  Recent changes reshuffled this code to update
the global node stats before the memcg ones, though, stretching the race
window out to an extent where people can reproduce the problem.

Update test_clear_page_writeback() to look up and pin page->mem_cgroup
before clearing PG_writeback, then not use that pointer afterward.  It
is a partial revert of 62cccb8c ("mm: simplify lock_page_memcg()")
but leaves the pageref-holding callsites that aren't affected alone.

Link: http://lkml.kernel.org/r/20170809183825.GA26387@cmpxchg.org
Fixes: 62cccb8c ("mm: simplify lock_page_memcg()")
Signed-off-by: NJohannes Weiner <hannes@cmpxchg.org>
Reported-by: NJaegeuk Kim <jaegeuk@kernel.org>
Tested-by: NJaegeuk Kim <jaegeuk@kernel.org>
Reported-by: NBradley Bolen <bradleybolen@gmail.com>
Tested-by: NBrad Bolen <bradleybolen@gmail.com>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: <stable@vger.kernel.org>	[4.6+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Due to commit e6afc8ac ("udp: remove
headers from UDP packets before queueing"), when udp packets are being
peeked the requested extra offset is always 0 as there is no need to skip
the udp header.  However, when the offset is 0 and the next skb is
of length 0, it is only returned once.  The behaviour can be seen with
the following python script:

from socket import *;
f=socket(AF_INET6, SOCK_DGRAM | SOCK_NONBLOCK, 0);
g=socket(AF_INET6, SOCK_DGRAM | SOCK_NONBLOCK, 0);
f.bind(('::', 0));
addr=('::1', f.getsockname()[1]);
g.sendto(b'', addr)
g.sendto(b'b', addr)
print(f.recvfrom(10, MSG_PEEK));
print(f.recvfrom(10, MSG_PEEK));

Where the expected output should be the empty string twice.

Instead, make sk_peek_offset return negative values, and pass those values
to __skb_try_recv_datagram/__skb_try_recv_from_queue.  If the passed offset
to __skb_try_recv_from_queue is negative, the checked skb is never skipped.
__skb_try_recv_from_queue will then ensure the offset is reset back to 0
if a peek is requested without an offset, unless no packets are found.

Also simplify the if condition in __skb_try_recv_from_queue.  If _off is
greater then 0, and off is greater then or equal to skb->len, then
(_off || skb->len) must always be true assuming skb->len >= 0 is always
true.

Also remove a redundant check around a call to sk_peek_offset in af_unix.c,
as it double checked if MSG_PEEK was set in the flags.

V2:
 - Moved the negative fixup into __skb_try_recv_from_queue, and remove now
redundant checks
 - Fix peeking in udp{,v6}_recvmsg to report the right value when the
offset is 0

V3:
 - Marked new branch in __skb_try_recv_from_queue as unlikely.
Signed-off-by: NMatthew Dawson <matthew@mjdsystems.ca>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The hardlockup detector on x86 uses a performance counter based on unhalted
CPU cycles and a periodic hrtimer. The hrtimer period is about 2/5 of the
performance counter period, so the hrtimer should fire 2-3 times before the
performance counter NMI fires. The NMI code checks whether the hrtimer
fired since the last invocation. If not, it assumess a hard lockup.

The calculation of those periods is based on the nominal CPU
frequency. Turbo modes increase the CPU clock frequency and therefore
shorten the period of the perf/NMI watchdog. With extreme Turbo-modes (3x
nominal frequency) the perf/NMI period is shorter than the hrtimer period
which leads to false positives.

A simple fix would be to shorten the hrtimer period, but that comes with
the side effect of more frequent hrtimer and softlockup thread wakeups,
which is not desired.

Implement a low pass filter, which checks the perf/NMI period against
kernel time. If the perf/NMI fires before 4/5 of the watchdog period has
elapsed then the event is ignored and postponed to the next perf/NMI.

That solves the problem and avoids the overhead of shorter hrtimer periods
and more frequent softlockup thread wakeups.

Fixes: 58687acb ("lockup_detector: Combine nmi_watchdog and softlockup detector")
Reported-and-tested-by: NKan Liang <Kan.liang@intel.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: dzickus@redhat.com
Cc: prarit@redhat.com
Cc: ak@linux.intel.com
Cc: babu.moger@oracle.com
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: acme@redhat.com
Cc: stable@vger.kernel.org
Cc: atomlin@redhat.com
Cc: akpm@linux-foundation.org
Cc: torvalds@linux-foundation.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1708150931310.1886@nanos

Christian Brauner reported that if you use the TIOCGPTPEER ioctl() to
get a slave pty file descriptor, the resulting file descriptor doesn't
look right in /proc/<pid>/fd/<fd>.  In particular, he wanted to use
readlink() on /proc/self/fd/<fd> to get the pathname of the slave pty
(basically implementing "ptsname{_r}()").

The reason for that was that we had generated the wrong 'struct path'
when we create the pty in ptmx_open().

In particular, the dentry was correct, but the vfsmount pointed to the
mount of the ptmx node. That _can_ be correct - in case you use
"/dev/pts/ptmx" to open the master - but usually is not.  The normal
case is to use /dev/ptmx, which then looks up the pts/ directory, and
then the vfsmount of the ptmx node is obviously the /dev directory, not
the /dev/pts/ directory.

We actually did have the right vfsmount available, but in the wrong
place (it gets looked up in 'devpts_acquire()' when we get a reference
to the pts filesystem), and so ptmx_open() used the wrong mnt pointer.

The end result of this confusion was that the pty worked fine, but when
if you did TIOCGPTPEER to get the slave side of the pty, end end result
would also work, but have that dodgy 'struct path'.

And then when doing "d_path()" on to get the pathname, the vfsmount
would not match the root of the pts directory, and d_path() would return
an empty pathname thinking that the entry had escaped a bind mount into
another mount.

This fixes the problem by making devpts_acquire() return the vfsmount
for the pts filesystem, allowing ptmx_open() to trivially just use the
right mount for the pts dentry, and create the proper 'struct path'.
Reported-by: NChristian Brauner <christian.brauner@ubuntu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Acked-by: NEric Biederman <ebiederm@xmission.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Releasing a zone write lock only when the write commnand that acquired
the lock completes can cause deadlocks due to potential command
reordering if the lock owning request is requeued and not executed. This
problem exists only with the scsi-mq path as, unlike the legacy path,
requests are moved out of the dispatch queue before being prepared and
so before locking a zone for a write command.

Since sd_uninit_cmnd() is now always called when a request is requeued,
call sd_zbc_write_unlock_zone() from that function for write requests
that acquired a zone lock instead of from sd_done(). Acquisition of a zone
lock by a write command is indicated using the new command
flag SCMD_ZONE_WRITE_LOCK.
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NBart Van Assche <Bart.VanAssche@wdc.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

While working on yet another syzkaller report, I found
that our IP_MAX_MTU enforcements were not properly done.

gcc seems to reload dev->mtu for min(dev->mtu, IP_MAX_MTU), and
final result can be bigger than IP_MAX_MTU :/

This is a problem because device mtu can be changed on other cpus or
threads.

While this patch does not fix the issue I am working on, it is
probably worth addressing it.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

As found by syzkaller, malicious users can set whatever tx_queue_len
on a tun device and eventually crash the kernel.

Lets remove the ALIGN(XXX, SMP_CACHE_BYTES) thing since a small
ring buffer is not fast anyway.

Fixes: 2e0ab8ca ("ptr_ring: array based FIFO for pointers")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Jason Wang <jasowang@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NTonghao Zhang <xiangxia.m.yue@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Based on a syzkaller report [1], I found that a per cpu allocation
failure in snmp6_alloc_dev() would then lead to NULL dereference in
ip6_route_dev_notify().

It seems this is a very old bug, thus no Fixes tag in this submission.

Let's add in6_dev_put_clear() helper, as we will probably use
it elsewhere (once available/present in net-next)

[1]
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 1 PID: 17294 Comm: syz-executor6 Not tainted 4.13.0-rc2+ #10
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff88019f456680 task.stack: ffff8801c6e58000
RIP: 0010:__read_once_size include/linux/compiler.h:250 [inline]
RIP: 0010:atomic_read arch/x86/include/asm/atomic.h:26 [inline]
RIP: 0010:refcount_sub_and_test+0x7d/0x1b0 lib/refcount.c:178
RSP: 0018:ffff8801c6e5f1b0 EFLAGS: 00010202
RAX: 0000000000000037 RBX: dffffc0000000000 RCX: ffffc90005d25000
RDX: ffff8801c6e5f218 RSI: ffffffff82342bbf RDI: 0000000000000001
RBP: ffff8801c6e5f240 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 1ffff10038dcbe37
R13: 0000000000000006 R14: 0000000000000001 R15: 00000000000001b8
FS:  00007f21e0429700(0000) GS:ffff8801dc100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001ddbc22000 CR3: 00000001d632b000 CR4: 00000000001426e0
DR0: 0000000020000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 refcount_dec_and_test+0x1a/0x20 lib/refcount.c:211
 in6_dev_put include/net/addrconf.h:335 [inline]
 ip6_route_dev_notify+0x1c9/0x4a0 net/ipv6/route.c:3732
 notifier_call_chain+0x136/0x2c0 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x51/0x90 net/core/dev.c:1678
 call_netdevice_notifiers net/core/dev.c:1694 [inline]
 rollback_registered_many+0x91c/0xe80 net/core/dev.c:7107
 rollback_registered+0x1be/0x3c0 net/core/dev.c:7149
 register_netdevice+0xbcd/0xee0 net/core/dev.c:7587
 register_netdev+0x1a/0x30 net/core/dev.c:7669
 loopback_net_init+0x76/0x160 drivers/net/loopback.c:214
 ops_init+0x10a/0x570 net/core/net_namespace.c:118
 setup_net+0x313/0x710 net/core/net_namespace.c:294
 copy_net_ns+0x27c/0x580 net/core/net_namespace.c:418
 create_new_namespaces+0x425/0x880 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xae/0x1e0 kernel/nsproxy.c:206
 SYSC_unshare kernel/fork.c:2347 [inline]
 SyS_unshare+0x653/0xfa0 kernel/fork.c:2297
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4512c9
RSP: 002b:00007f21e0428c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 0000000000718150 RCX: 00000000004512c9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000062020200
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004b973d
R13: 00000000ffffffff R14: 000000002001d000 R15: 00000000000002dd
Code: 50 2b 34 82 c7 00 f1 f1 f1 f1 c7 40 04 04 f2 f2 f2 c7 40 08 f3 f3
f3 f3 e8 a1 43 39 ff 4c 89 f8 48 8b 95 70 ff ff ff 48 c1 e8 03 <0f> b6
0c 18 4c 89 f8 83 e0 07 83 c0 03 38 c8 7c 08 84 c9 0f 85
RIP: __read_once_size include/linux/compiler.h:250 [inline] RSP:
ffff8801c6e5f1b0
RIP: atomic_read arch/x86/include/asm/atomic.h:26 [inline] RSP:
ffff8801c6e5f1b0
RIP: refcount_sub_and_test+0x7d/0x1b0 lib/refcount.c:178 RSP:
ffff8801c6e5f1b0
---[ end trace e441d046c6410d31 ]---
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The struct iommu_device has a 'struct device' embedded into
it, not as a pointer, but the whole struct. In the
conversion of the iommu drivers to use struct iommu_device
it was forgotten that the relase function for that struct
device simply calls kfree() on the pointer.

This frees memory that was never allocated and causes memory
corruption.

To fix this issue, use a pointer to struct device instead of
embedding the whole struct. This needs some updates in the
iommu sysfs code as well as the Intel VT-d and AMD IOMMU
driver.
Reported-by: NSebastian Ott <sebott@linux.vnet.ibm.com>
Fixes: 39ab9555 ('iommu: Add sysfs bindings for struct iommu_device')
Cc: stable@vger.kernel.org # >= v4.11
Signed-off-by: NJoerg Roedel <jroedel@suse.de>

copy_linear_skb() is broken; both of its callers actually
expect 'len' to be the amount we are trying to copy,
not the offset of the end.
Fix it keeping the meanings of arguments in sync with what the
callers (both of them) expect.
Also restore a saner behavior on EFAULT (i.e. preserving
the iov_iter position in case of failure):

The commit fd851ba9 ("udp: harden copy_linear_skb()")
avoids the more destructive effect of the buggy
copy_linear_skb(), e.g. no more invalid memory access, but
said function still behaves incorrectly: when peeking with
offset it can fail with EINVAL instead of copying the
appropriate amount of memory.
Reported-by: NSasha Levin <alexander.levin@verizon.com>
Fixes: b65ac446 ("udp: try to avoid 2 cache miss on dequeue")
Fixes: fd851ba9 ("udp: harden copy_linear_skb()")
Signed-off-by: NAl Viro <viro@ZenIV.linux.org.uk>
Acked-by: NPaolo Abeni <pabeni@redhat.com>
Tested-by: NSasha Levin <alexander.levin@verizon.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When bit4 is set in the PCIe Device Control register, it indicates
whether the device is permitted to use relaxed ordering.
On some platforms using relaxed ordering can have performance issues or
due to erratum can cause data-corruption. In such cases devices must avoid
using relaxed ordering.

The patch adds a new flag PCI_DEV_FLAGS_NO_RELAXED_ORDERING to indicate that
Relaxed Ordering (RO) attribute should not be used for Transaction Layer
Packets (TLP) targeted towards these affected root complexes.

This patch checks if there is any node in the hierarchy that indicates that
using relaxed ordering is not safe. In such cases the patch turns off the
relaxed ordering by clearing the capability for this device.
Signed-off-by: NCasey Leedom <leedom@chelsio.com>
Signed-off-by: NDing Tianhong <dingtianhong@huawei.com>
Acked-by: NAshok Raj <ashok.raj@intel.com>
Acked-by: NAlexander Duyck <alexander.h.duyck@intel.com>
Acked-by: NCasey Leedom <leedom@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzkaller got crashes with CONFIG_HARDENED_USERCOPY=y configs.

Issue here is that recvfrom() can be used with user buffer of Z bytes,
and SO_PEEK_OFF of X bytes, from a skb with Y bytes, and following
condition :

Z < X < Y

kernel BUG at mm/usercopy.c:72!
invalid opcode: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 2917 Comm: syzkaller842281 Not tainted 4.13.0-rc3+ #16
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS
Google 01/01/2011
task: ffff8801d2fa40c0 task.stack: ffff8801d1fe8000
RIP: 0010:report_usercopy mm/usercopy.c:64 [inline]
RIP: 0010:__check_object_size+0x3ad/0x500 mm/usercopy.c:264
RSP: 0018:ffff8801d1fef8a8 EFLAGS: 00010286
RAX: 0000000000000078 RBX: ffffffff847102c0 RCX: 0000000000000000
RDX: 0000000000000078 RSI: 1ffff1003a3fded5 RDI: ffffed003a3fdf09
RBP: ffff8801d1fef998 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801d1ea480e
R13: fffffffffffffffa R14: ffffffff84710280 R15: dffffc0000000000
FS:  0000000001360880(0000) GS:ffff8801dc000000(0000)
knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000202ecfe4 CR3: 00000001d1ff8000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 check_object_size include/linux/thread_info.h:108 [inline]
 check_copy_size include/linux/thread_info.h:139 [inline]
 copy_to_iter include/linux/uio.h:105 [inline]
 copy_linear_skb include/net/udp.h:371 [inline]
 udpv6_recvmsg+0x1040/0x1af0 net/ipv6/udp.c:395
 inet_recvmsg+0x14c/0x5f0 net/ipv4/af_inet.c:793
 sock_recvmsg_nosec net/socket.c:792 [inline]
 sock_recvmsg+0xc9/0x110 net/socket.c:799
 SYSC_recvfrom+0x2d6/0x570 net/socket.c:1788
 SyS_recvfrom+0x40/0x50 net/socket.c:1760
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Fixes: b65ac446 ("udp: try to avoid 2 cache miss on dequeue")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

MIN_NAPI_ID is used in various places outside of
CONFIG_NET_RX_BUSY_POLL wrapping, so when it's not set
we run into build errors such as:

  net/core/dev.c: In function 'dev_get_by_napi_id':
  net/core/dev.c:886:16: error: ‘MIN_NAPI_ID’ undeclared (first use in this function)
    if (napi_id < MIN_NAPI_ID)
                  ^~~~~~~~~~~

Thus, have MIN_NAPI_ID always defined to fix these errors.
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The patch c4adfc82 ("bonding: make speed, duplex setting consistent
with link state") puts the link state to down if
bond_update_speed_duplex() cannot retrieve speed and duplex settings.
Assumably the patch was written with 802.3ad mode in mind which relies
on link speed/duplex settings. For other modes like active-backup these
settings are not required. Thus, only for these other modes, this patch
reintroduces support for slaves that do not support reporting speed or
duplex such as wireless devices. This fixes the regression reported in
bug 196547 (https://bugzilla.kernel.org/show_bug.cgi?id=196547).

Fixes: c4adfc82 ("bonding: make speed, duplex setting consistent
with link state")
Signed-off-by: NAndreas Born <futur.andy@googlemail.com>
Acked-by: NMahesh Bandewar <maheshb@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Nadav reported parallel MADV_DONTNEED on same range has a stale TLB
problem and Mel fixed it[1] and found same problem on MADV_FREE[2].

Quote from Mel Gorman:
 "The race in question is CPU 0 running madv_free and updating some PTEs
  while CPU 1 is also running madv_free and looking at the same PTEs.
  CPU 1 may have writable TLB entries for a page but fail the pte_dirty
  check (because CPU 0 has updated it already) and potentially fail to
  flush.

  Hence, when madv_free on CPU 1 returns, there are still potentially
  writable TLB entries and the underlying PTE is still present so that a
  subsequent write does not necessarily propagate the dirty bit to the
  underlying PTE any more. Reclaim at some unknown time at the future
  may then see that the PTE is still clean and discard the page even
  though a write has happened in the meantime. I think this is possible
  but I could have missed some protection in madv_free that prevents it
  happening."

This patch aims for solving both problems all at once and is ready for
other problem with KSM, MADV_FREE and soft-dirty story[3].

TLB batch API(tlb_[gather|finish]_mmu] uses [inc|dec]_tlb_flush_pending
and mmu_tlb_flush_pending so that when tlb_finish_mmu is called, we can
catch there are parallel threads going on.  In that case, forcefully,
flush TLB to prevent for user to access memory via stale TLB entry
although it fail to gather page table entry.

I confirmed this patch works with [4] test program Nadav gave so this
patch supersedes "mm: Always flush VMA ranges affected by zap_page_range
v2" in current mmotm.

NOTE:

This patch modifies arch-specific TLB gathering interface(x86, ia64,
s390, sh, um).  It seems most of architecture are straightforward but
s390 need to be careful because tlb_flush_mmu works only if
mm->context.flush_mm is set to non-zero which happens only a pte entry
really is cleared by ptep_get_and_clear and friends.  However, this
problem never changes the pte entries but need to flush to prevent
memory access from stale tlb.

[1] http://lkml.kernel.org/r/20170725101230.5v7gvnjmcnkzzql3@techsingularity.net
[2] http://lkml.kernel.org/r/20170725100722.2dxnmgypmwnrfawp@suse.de
[3] http://lkml.kernel.org/r/BD3A0EBE-ECF4-41D4-87FA-C755EA9AB6BD@gmail.com
[4] https://patchwork.kernel.org/patch/9861621/

[minchan@kernel.org: decrease tlb flush pending count in tlb_finish_mmu]
  Link: http://lkml.kernel.org/r/20170808080821.GA31730@bbox
Link: http://lkml.kernel.org/r/20170802000818.4760-7-namit@vmware.comSigned-off-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NNadav Amit <namit@vmware.com>
Reported-by: NNadav Amit <namit@vmware.com>
Reported-by: NMel Gorman <mgorman@techsingularity.net>
Acked-by: NMel Gorman <mgorman@techsingularity.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, tlb_flush_pending is used only for CONFIG_[NUMA_BALANCING|
COMPACTION] but upcoming patches to solve subtle TLB flush batching
problem will use it regardless of compaction/NUMA so this patch doesn't
remove the dependency.

[akpm@linux-foundation.org: remove more ifdefs from world's ugliest printk statement]
Link: http://lkml.kernel.org/r/20170802000818.4760-6-namit@vmware.comSigned-off-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NNadav Amit <namit@vmware.com>
Acked-by: NMel Gorman <mgorman@techsingularity.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch is a preparatory patch for solving race problems caused by
TLB batch.  For that, we will increase/decrease TLB flush pending count
of mm_struct whenever tlb_[gather|finish]_mmu is called.

Before making it simple, this patch separates architecture specific part
and rename it to arch_tlb_[gather|finish]_mmu and generic part just
calls it.

It shouldn't change any behavior.

Link: http://lkml.kernel.org/r/20170802000818.4760-5-namit@vmware.comSigned-off-by: NMinchan Kim <minchan@kernel.org>
Signed-off-by: NNadav Amit <namit@vmware.com>
Acked-by: NMel Gorman <mgorman@techsingularity.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Reading tlb_flush_pending while the page-table lock is taken does not
require a barrier, since the lock/unlock already acts as a barrier.
Removing the barrier in mm_tlb_flush_pending() to address this issue.

However, migrate_misplaced_transhuge_page() calls mm_tlb_flush_pending()
while the page-table lock is already released, which may present a
problem on architectures with weak memory model (PPC).  To deal with
this case, a new parameter is added to mm_tlb_flush_pending() to
indicate if it is read without the page-table lock taken, and calling
smp_mb__after_unlock_lock() in this case.

Link: http://lkml.kernel.org/r/20170802000818.4760-3-namit@vmware.comSigned-off-by: NNadav Amit <namit@vmware.com>
Acked-by: NRik van Riel <riel@redhat.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Patch series "fixes of TLB batching races", v6.

It turns out that Linux TLB batching mechanism suffers from various
races.  Races that are caused due to batching during reclamation were
recently handled by Mel and this patch-set deals with others.  The more
fundamental issue is that concurrent updates of the page-tables allow
for TLB flushes to be batched on one core, while another core changes
the page-tables.  This other core may assume a PTE change does not
require a flush based on the updated PTE value, while it is unaware that
TLB flushes are still pending.

This behavior affects KSM (which may result in memory corruption) and
MADV_FREE and MADV_DONTNEED (which may result in incorrect behavior).  A
proof-of-concept can easily produce the wrong behavior of MADV_DONTNEED.
Memory corruption in KSM is harder to produce in practice, but was
observed by hacking the kernel and adding a delay before flushing and
replacing the KSM page.

Finally, there is also one memory barrier missing, which may affect
architectures with weak memory model.

This patch (of 7):

Setting and clearing mm->tlb_flush_pending can be performed by multiple
threads, since mmap_sem may only be acquired for read in
task_numa_work().  If this happens, tlb_flush_pending might be cleared
while one of the threads still changes PTEs and batches TLB flushes.

This can lead to the same race between migration and
change_protection_range() that led to the introduction of
tlb_flush_pending.  The result of this race was data corruption, which
means that this patch also addresses a theoretically possible data
corruption.

An actual data corruption was not observed, yet the race was was
confirmed by adding assertion to check tlb_flush_pending is not set by
two threads, adding artificial latency in change_protection_range() and
using sysctl to reduce kernel.numa_balancing_scan_delay_ms.

Link: http://lkml.kernel.org/r/20170802000818.4760-2-namit@vmware.com
Fixes: 20841405 ("mm: fix TLB flush race between migration, and
change_protection_range")
Signed-off-by: NNadav Amit <namit@vmware.com>
Acked-by: NMel Gorman <mgorman@suse.de>
Acked-by: NRik van Riel <riel@redhat.com>
Acked-by: NMinchan Kim <minchan@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Vince reported the following rdpmc() testcase failure:

 > Failing test case:
 >
 >	fd=perf_event_open();
 >	addr=mmap(fd);
 >	exec()  // without closing or unmapping the event
 >	fd=perf_event_open();
 >	addr=mmap(fd);
 >	rdpmc()	// GPFs due to rdpmc being disabled

The problem is of course that exec() plays tricks with what is
current->mm, only destroying the old mappings after having
installed the new mm.

Fix this confusion by passing along vma->vm_mm instead of relying on
current->mm.
Reported-by: NVince Weaver <vincent.weaver@maine.edu>
Tested-by: NVince Weaver <vincent.weaver@maine.edu>
Signed-off-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: NAndy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: 1e0fb9ec ("perf: Add pmu callbacks to track event mapping and unmapping")
Link: http://lkml.kernel.org/r/20170802173930.cstykcqefmqt7jau@hirez.programming.kicks-ass.net
[ Minor cleanups. ]
Signed-off-by: NIngo Molnar <mingo@kernel.org>

At queue creation, the transport allocates a local job struct
(struct nvmet_fc_fcp_iod) for each possible element of the queue.
When a new CMD is received from the wire, a jobs struct is allocated
from the queue and then used for the duration of the command.
The job struct contains buffer space for the wire command iu. Thus,
upon allocation of the job struct, the cmd iu buffer is copied to
the job struct and the LLDD may immediately free/reuse the CMD IU
buffer passed in the call.

However, in some circumstances, due to the packetized nature of FC
and the api of the FC LLDD which may issue a hw command to send the
wire response, but the LLDD may not get the hw completion for the
command and upcall the nvmet_fc layer before a new command may be
asynchronously received on the wire. In other words, its possible
for the initiator to get the response from the wire, thus believe a
command slot free, and send a new command iu. The new command iu
may be received by the LLDD and passed to the transport before the
LLDD had serviced the hw completion and made the teardown calls for
the original job struct. As such, there is no available job struct
available for the new io. E.g. it appears like the host sent more
queue elements than the queue size. It didn't based on it's
understanding.

Rather than treat this as a hard connection failure queue the new
request until the job struct does free up. As the buffer isn't
copied as there's no job struct, a special return value must be
returned to the LLDD to signify to hold off on recycling the cmd
iu buffer.  And later, when a job struct is allocated and the
buffer copied, a new LLDD callback is introduced to notify the
LLDD and allow it to recycle it's command iu buffer.
Signed-off-by: NJames Smart <james.smart@broadcom.com>
Reviewed-by: NJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: NChristoph Hellwig <hch@lst.de>

The .data and .bss sections were modified in the generic linker script to
pull in sections named .data.<C identifier>, which are generated by gcc with
-ffunction-sections and -fdata-sections options.

The problem with this pattern is it can also match section names that Linux
defines explicitly, e.g., .data.unlikely. This can cause Linux sections to
get moved into the wrong place.

The way to avoid this is to use ".." separators for explicit section names
(the dot character is valid in a section name but not a C identifier).
However currently there are sections which don't follow this rule, so for
now just disable the wild card by default.

Example: http://marc.info/?l=linux-arm-kernel&m=150106824024221&w=2

Cc: <stable@vger.kernel.org> # 4.9
Fixes: b67067f1 ("kbuild: allow archs to select link dead code/data elimination")
Signed-off-by: NNicholas Piggin <npiggin@gmail.com>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

Some drivers handle rx buffer reordering internally (and by extension
handle also the rx ba session timer internally), but do not ofload the
addba/delba negotiation.
Add an api for these drivers to properly tear-down the ba session,
including sending a delba.
Signed-off-by: NNaftali Goldstein <naftali.goldstein@intel.com>
Signed-off-by: NLuca Coelho <luciano.coelho@intel.com>

Update deprecated references to Documentation/pinctrl.txt since it has been
moved to Documentation/driver-api/pinctl.rst.
Signed-off-by: NLudovic Desroches <ludovic.desroches@o2linux.fr>
Fixes: 5a9b7383 ("pinctrl.txt: move it to the driver-api book")
Signed-off-by: NLinus Walleij <linus.walleij@linaro.org>

This patch fixes a bug associated with iscsit_reset_np_thread()
that can occur during parallel configfs rmdir of a single iscsi_np
used across multiple iscsi-target instances, that would result in
hung task(s) similar to below where configfs rmdir process context
was blocked indefinately waiting for iscsi_np->np_restart_comp
to finish:

[ 6726.112076] INFO: task dcp_proxy_node_:15550 blocked for more than 120 seconds.
[ 6726.119440]       Tainted: G        W  O     4.1.26-3321 #2
[ 6726.125045] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 6726.132927] dcp_proxy_node_ D ffff8803f202bc88     0 15550      1 0x00000000
[ 6726.140058]  ffff8803f202bc88 ffff88085c64d960 ffff88083b3b1ad0 ffff88087fffeb08
[ 6726.147593]  ffff8803f202c000 7fffffffffffffff ffff88083f459c28 ffff88083b3b1ad0
[ 6726.155132]  ffff88035373c100 ffff8803f202bca8 ffffffff8168ced2 ffff8803f202bcb8
[ 6726.162667] Call Trace:
[ 6726.165150]  [<ffffffff8168ced2>] schedule+0x32/0x80
[ 6726.170156]  [<ffffffff8168f5b4>] schedule_timeout+0x214/0x290
[ 6726.176030]  [<ffffffff810caef2>] ? __send_signal+0x52/0x4a0
[ 6726.181728]  [<ffffffff8168d7d6>] wait_for_completion+0x96/0x100
[ 6726.187774]  [<ffffffff810e7c80>] ? wake_up_state+0x10/0x10
[ 6726.193395]  [<ffffffffa035d6e2>] iscsit_reset_np_thread+0x62/0xe0 [iscsi_target_mod]
[ 6726.201278]  [<ffffffffa0355d86>] iscsit_tpg_disable_portal_group+0x96/0x190 [iscsi_target_mod]
[ 6726.210033]  [<ffffffffa0363f7f>] lio_target_tpg_store_enable+0x4f/0xc0 [iscsi_target_mod]
[ 6726.218351]  [<ffffffff81260c5a>] configfs_write_file+0xaa/0x110
[ 6726.224392]  [<ffffffff811ea364>] vfs_write+0xa4/0x1b0
[ 6726.229576]  [<ffffffff811eb111>] SyS_write+0x41/0xb0
[ 6726.234659]  [<ffffffff8169042e>] system_call_fastpath+0x12/0x71

It would happen because each iscsit_reset_np_thread() sets state
to ISCSI_NP_THREAD_RESET, sends SIGINT, and then blocks waiting
for completion on iscsi_np->np_restart_comp.

However, if iscsi_np was active processing a login request and
more than a single iscsit_reset_np_thread() caller to the same
iscsi_np was blocked on iscsi_np->np_restart_comp, iscsi_np
kthread process context in __iscsi_target_login_thread() would
flush pending signals and only perform a single completion of
np->np_restart_comp before going back to sleep within transport
specific iscsit_transport->iscsi_accept_np code.

To address this bug, add a iscsi_np->np_reset_count and update
__iscsi_target_login_thread() to keep completing np->np_restart_comp
until ->np_reset_count has reached zero.
Reported-by: NGary Guo <ghg@datera.io>
Tested-by: NGary Guo <ghg@datera.io>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: stable@vger.kernel.org # 3.10+
Signed-off-by: NNicholas Bellinger <nab@linux-iscsi.org>

The extended address vector is the highest bit in be32 variable,
but it was compared with the lowest. This patch fixes the endianness
of that check and removes already declared define.

Fixes: 17d2f88f ("IB/mlx5: Add ODP atomics support")
Reviewed-by: NArtemy Kovalyov <artemyko@mellanox.com>
Signed-off-by: NLeon Romanovsky <leonro@mellanox.com>
Signed-off-by: NDoug Ledford <dledford@redhat.com>

Pure refactor. This helper will be required in the xmit timer fix
later in the patch series. (Because the TLP logic will want to make
this calculation.)

Fixes: 6ba8a3b1 ("tcp: Tail loss probe (TLP)")
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NNandita Dukkipati <nanditad@google.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>