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>

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>

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>

Kernel panic when calling the IRQ-safe __get_user_pages_fast in NMI
handler.

The bug was introduced by commit 2947ba05 ("x86/mm/gup: Switch GUP
to the generic get_user_page_fast() implementation").

The original x86 __get_user_page_fast used plain get_page() or
page_ref_add().  However, the generic __get_user_page_fast uses
page_cache_get_speculative(), which has VM_BUG_ON(in_interrupt()).

There is no reason to prevent page_cache_get_speculative from using in
interrupt context.  According to the author, putting a BUG_ON there is
just because the code is not verifying correctness of interrupt races.
I did some tests in interrupt context.  There is no issue found.

Removing VM_BUG_ON(in_interrupt()) for page_cache_get_speculative().

Link: http://lkml.kernel.org/r/1501609146-59730-1-git-send-email-kan.liang@intel.com
Fixes: 2947ba05 ("x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation")
Signed-off-by: NKan Liang <kan.liang@intel.com>
Cc: Jens Axboe <axboe@fb.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ying Huang <ying.huang@intel.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

In codepaths that use the begin/retry interface for reading
mems_allowed_seq with irqs disabled, there exists a race condition that
stalls the patch process after only modifying a subset of the
static_branch call sites.

This problem manifested itself as a deadlock in the slub allocator,
inside get_any_partial.  The loop reads mems_allowed_seq value (via
read_mems_allowed_begin), performs the defrag operation, and then
verifies the consistency of mem_allowed via the read_mems_allowed_retry
and the cookie returned by xxx_begin.

The issue here is that both begin and retry first check if cpusets are
enabled via cpusets_enabled() static branch.  This branch can be
rewritted dynamically (via cpuset_inc) if a new cpuset is created.  The
x86 jump label code fully synchronizes across all CPUs for every entry
it rewrites.  If it rewrites only one of the callsites (specifically the
one in read_mems_allowed_retry) and then waits for the
smp_call_function(do_sync_core) to complete while a CPU is inside the
begin/retry section with IRQs off and the mems_allowed value is changed,
we can hang.

This is because begin() will always return 0 (since it wasn't patched
yet) while retry() will test the 0 against the actual value of the seq
counter.

The fix is to use two different static keys: one for begin
(pre_enable_key) and one for retry (enable_key).  In cpuset_inc(), we
first bump the pre_enable key to ensure that cpuset_mems_allowed_begin()
always return a valid seqcount if are enabling cpusets.  Similarly, when
disabling cpusets via cpuset_dec(), we first ensure that callers of
cpuset_mems_allowed_retry() will start ignoring the seqcount value
before we let cpuset_mems_allowed_begin() return 0.

The relevant stack traces of the two stuck threads:

  CPU: 1 PID: 1415 Comm: mkdir Tainted: G L  4.9.36-00104-g540c51286237 #4
  Hardware name: Default string Default string/Hardware, BIOS 4.29.1-20170526215256 05/26/2017
  task: ffff8817f9c28000 task.stack: ffffc9000ffa4000
  RIP: smp_call_function_many+0x1f9/0x260
  Call Trace:
    smp_call_function+0x3b/0x70
    on_each_cpu+0x2f/0x90
    text_poke_bp+0x87/0xd0
    arch_jump_label_transform+0x93/0x100
    __jump_label_update+0x77/0x90
    jump_label_update+0xaa/0xc0
    static_key_slow_inc+0x9e/0xb0
    cpuset_css_online+0x70/0x2e0
    online_css+0x2c/0xa0
    cgroup_apply_control_enable+0x27f/0x3d0
    cgroup_mkdir+0x2b7/0x420
    kernfs_iop_mkdir+0x5a/0x80
    vfs_mkdir+0xf6/0x1a0
    SyS_mkdir+0xb7/0xe0
    entry_SYSCALL_64_fastpath+0x18/0xad

  ...

  CPU: 2 PID: 1 Comm: init Tainted: G L  4.9.36-00104-g540c51286237 #4
  Hardware name: Default string Default string/Hardware, BIOS 4.29.1-20170526215256 05/26/2017
  task: ffff8818087c0000 task.stack: ffffc90000030000
  RIP: int3+0x39/0x70
  Call Trace:
    <#DB> ? ___slab_alloc+0x28b/0x5a0
    <EOE> ? copy_process.part.40+0xf7/0x1de0
    __slab_alloc.isra.80+0x54/0x90
    copy_process.part.40+0xf7/0x1de0
    copy_process.part.40+0xf7/0x1de0
    kmem_cache_alloc_node+0x8a/0x280
    copy_process.part.40+0xf7/0x1de0
    _do_fork+0xe7/0x6c0
    _raw_spin_unlock_irq+0x2d/0x60
    trace_hardirqs_on_caller+0x136/0x1d0
    entry_SYSCALL_64_fastpath+0x5/0xad
    do_syscall_64+0x27/0x350
    SyS_clone+0x19/0x20
    do_syscall_64+0x60/0x350
    entry_SYSCALL64_slow_path+0x25/0x25

Link: http://lkml.kernel.org/r/20170731040113.14197-1-dmitriyz@waymo.com
Fixes: 46e700ab ("mm, page_alloc: remove unnecessary taking of a seqlock when cpusets are disabled")
Signed-off-by: NDima Zavin <dmitriyz@waymo.com>
Reported-by: NCliff Spradlin <cspradlin@waymo.com>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christopher Lameter <cl@linux.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.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>

The kerneldoc comment for kthread_create() had an incorrect argument
name, leading to a warning in the docs build.

Correct it, and make one more small step toward a warning-free build.

Link: http://lkml.kernel.org/r/20170724135916.7f486c6f@lwn.netSigned-off-by: NJonathan Corbet <corbet@lwn.net>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Nadav Amit identified a theoritical race between page reclaim and
mprotect due to TLB flushes being batched outside of the PTL being held.

He described the race as follows:

        CPU0                            CPU1
        ----                            ----
                                        user accesses memory using RW PTE
                                        [PTE now cached in TLB]
        try_to_unmap_one()
        ==> ptep_get_and_clear()
        ==> set_tlb_ubc_flush_pending()
                                        mprotect(addr, PROT_READ)
                                        ==> change_pte_range()
                                        ==> [ PTE non-present - no flush ]

                                        user writes using cached RW PTE
        ...

        try_to_unmap_flush()

The same type of race exists for reads when protecting for PROT_NONE and
also exists for operations that can leave an old TLB entry behind such
as munmap, mremap and madvise.

For some operations like mprotect, it's not necessarily a data integrity
issue but it is a correctness issue as there is a window where an
mprotect that limits access still allows access.  For munmap, it's
potentially a data integrity issue although the race is massive as an
munmap, mmap and return to userspace must all complete between the
window when reclaim drops the PTL and flushes the TLB.  However, it's
theoritically possible so handle this issue by flushing the mm if
reclaim is potentially currently batching TLB flushes.

Other instances where a flush is required for a present pte should be ok
as either the page lock is held preventing parallel reclaim or a page
reference count is elevated preventing a parallel free leading to
corruption.  In the case of page_mkclean there isn't an obvious path
that userspace could take advantage of without using the operations that
are guarded by this patch.  Other users such as gup as a race with
reclaim looks just at PTEs.  huge page variants should be ok as they
don't race with reclaim.  mincore only looks at PTEs.  userfault also
should be ok as if a parallel reclaim takes place, it will either fault
the page back in or read some of the data before the flush occurs
triggering a fault.

Note that a variant of this patch was acked by Andy Lutomirski but this
was for the x86 parts on top of his PCID work which didn't make the 4.13
merge window as expected.  His ack is dropped from this version and
there will be a follow-on patch on top of PCID that will include his
ack.

[akpm@linux-foundation.org: tweak comments]
[akpm@linux-foundation.org: fix spello]
Link: http://lkml.kernel.org/r/20170717155523.emckq2esjro6hf3z@suse.deReported-by: NNadav Amit <nadav.amit@gmail.com>
Signed-off-by: NMel Gorman <mgorman@suse.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: <stable@vger.kernel.org>	[v4.4+]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

During teardown, accesses to memslots and buses are using
rcu_dereference_protected with an always-true condition because
these accesses are done outside the usual mutexes.  This
is because the last reference is gone and there cannot be any
concurrent modifications, but rcu_dereference_protected is
ugly and unobvious.

Instead, check the refcount in kvm_get_bus and __kvm_memslots.
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NRadim Krčmář <rkrcmar@redhat.com>

Currently when WoL is supported but disabled, ethtool reports:
"Supports Wake-on: d".
Fix the indication of Wol support, so that the indication
remains "g" all the time if the NIC supports WoL.

Tested:
As accepted, when NIC supports WoL- ethtool reports:
	Supports Wake-on: g
	Wake-on: d
when NIC doesn't support WoL- ethtool reports:
        Supports Wake-on: d
        Wake-on: d

Fixes: 14c07b13 ("mlx4: Wake on LAN support")
Signed-off-by: NInbar Karmy <inbark@mellanox.com>
Signed-off-by: NTariq Toukan <tariqt@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

All timings in nand_sdr_timings are expressed in picoseconds but some
of them may not fit in an u32.
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>
Fixes: 204e7ecd ("mtd: nand: Add a few more timings to nand_sdr_timings")
Reported-by: NAlexander Dahl <ada@thorsis.com>
Cc: <stable@vger.kernel.org>
Reviewed-by: NAlexander Dahl <ada@thorsis.com>
Tested-by: NAlexander Dahl <ada@thorsis.com>
Signed-off-by: NBoris Brezillon <boris.brezillon@free-electrons.com>

The implementation of PCI workarounds may require that the device is reset
from its probe function.  This implies that the PCI device lock is already
held, and makes calling pci_reset_function() impossible (since it will
itself try to take that lock).

Add pci_reset_function_locked(), which is the equivalent of
pci_reset_function(), except that it requires the PCI device lock to be
already held by the caller.
Tested-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
[bhelgaas: folded in fix for conflict with 52354b9d ("PCI: Remove
__pci_dev_reset() and pci_dev_reset()")]
Signed-off-by: NBjorn Helgaas <bhelgaas@google.com>
Cc: stable@vger.kernel.org	# 4.11: 52354b9d: PCI: Remove __pci_dev_reset() and pci_dev_reset()
Cc: stable@vger.kernel.org	# 4.11

__user should be used to identify user pointers and not __u64
variables containing pointers.
Signed-off-by: NJordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: NRob Clark <robdclark@gmail.com>

Many PTP drivers required to perform some asynchronous or periodic work,
like periodically handling PHC counter overflow or handle delayed timestamp
for RX/TX network packets. In most of the cases, such work is implemented
using workqueues. Unfortunately, Kernel workqueues might introduce
significant delay in work scheduling under high system load and on -RT,
which could cause misbehavior of PTP drivers due to internal counter
overflow, for example, and there is no way to tune its execution policy and
priority manuallly.

Hence, The kthread_worker can be used insted of workqueues, as it create
separte named kthread for each worker and its its execution policy and
priority can be configured using chrt tool.

This prblem was reported for two drivers TI CPSW CPTS and dp83640, so
instead of modifying each of these driver it was proposed to add PTP
auxiliary worker to the PHC subsystem.

The patch adds PTP auxiliary worker in PHC subsystem using kthread_worker
and kthread_delayed_work and introduces two new PHC subsystem APIs:

- long (*do_aux_work)(struct ptp_clock_info *ptp) callback in
ptp_clock_info structure, which driver should assign if it require to
perform asynchronous or periodic work. Driver should return the delay of
the PTP next auxiliary work scheduling time (>=0) or negative value in case
further scheduling is not required.

- int ptp_schedule_worker(struct ptp_clock *ptp, unsigned long delay) which
allows schedule PTP auxiliary work.

The name of kthread_worker thread corresponds PTP PHC device name "ptp%d".
Signed-off-by: NGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The verifier is allocated on the stack, but the EXCHANGE_ID RPC call was
changed to be asynchronous by commit 8d89bd70. If we interrrupt
the call to rpc_wait_for_completion_task(), we can therefore end up
transmitting random stack contents in lieu of the verifier.

Fixes: 8d89bd70 ("NFS setup async exchange_id")
Cc: stable@vger.kernel.org # v4.9+
Signed-off-by: NTrond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: NAnna Schumaker <Anna.Schumaker@Netapp.com>

This is needed so that the OSDs can regenerate the missing set at the
start of a new interval where support for recovery deletes changed.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
Reviewed-by: NSage Weil <sage@redhat.com>

There is now a fallback to a choose_arg index of -1 if there isn't
a pool-specific choose_arg set.  If you create a per-pool weight-set,
that works for that pool.  Otherwise we try the compat/default one.  If
that doesn't exist either, then we use the normal CRUSH weights.
Signed-off-by: NIlya Dryomov <idryomov@gmail.com>
Reviewed-by: NSage Weil <sage@redhat.com>

Since commit 67a51780 ("ipv6: udp: leverage scratch area
helpers") udp6_recvmsg() read the skb len from the scratch area,
to avoid a cache miss.
But the UDP6 rx path support RFC 2675 UDPv6 jumbograms, and their
length exceeds the 16 bits available in the scratch area. As a side
effect the length returned by recvmsg() is:
<ingress datagram len> % (1<<16)

This commit addresses the issue allocating one more bit in the
IP6CB flags field and setting it for incoming jumbograms.
Such field is still in the first cacheline, so at recvmsg()
time we can check it and fallback to access skb->len if
required, without a measurable overhead.

Fixes: 67a51780 ("ipv6: udp: leverage scratch area helpers")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Hopefully making clear that it is not needed for new drivers.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>

Up until recently sync_file were create to export a single dma-fence to
userspace, and so we could canabalise a bit insie dma-fence to mark
whether or not we had enable polling for the sync_file itself. However,
with the advent of syncobj, we do allow userspace to create multiple
sync_files for a single dma-fence. (Similarly, that the sw-sync
validation framework also started returning multiple sync-files wrapping
a single dma-fence for a syncpt also triggering the problem.)

This patch reverts my suggestion in commit e2416553
("dma-buf/sync_file: only enable fence signalling on poll()") to use a
single bit in the shared dma-fence and restores the sync_file->flags for
tracking the bits individually.
Reported-by: NGustavo Padovan <gustavo.padovan@collabora.com>
Fixes: f1e8c671 ("dma-buf/sw-sync: Use an rbtree to sort fences in the timeline")
Fixes: e9083420 ("drm: introduce sync objects (v4)")
Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Sean Paul <seanpaul@chromium.org>
Cc: Gustavo Padovan <gustavo@padovan.org>
Cc: dri-devel@lists.freedesktop.org
Cc: <drm-intel-fixes@lists.freedesktop.org> # v4.13-rc1+
Signed-off-by: NGustavo Padovan <gustavo.padovan@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170728212951.7818-1-chris@chris-wilson.co.uk
(cherry picked from commit db1fc97c)

Two variables in ext4_inode_info, i_reserved_meta_blocks and
i_allocated_meta_blocks, are unused.  Removing them saves a little
memory per in-memory inode and cleans up clutter in several tracepoints.
Adjust tracepoint output from ext4_alloc_da_blocks() for consistency
and fix a typo and whitespace near these changes.
Signed-off-by: NEric Whitney <enwlinux@gmail.com>
Signed-off-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NJan Kara <jack@suse.cz>

The work-around for Qualcomm Technologies QDF2400 Erratum 44 hinges on a
global variable defined in the pl011 driver.  The ACPI SPCR parsing code
determines whether the work-around is needed, and if so, it changes the
console name from "pl011" to "qdf2400_e44".  The expectation is that
the pl011 driver will implement the work-around when it sees the console
name.  The global variable qdf2400_e44_present is set when that happens.

The problem is that work-around needs to be enabled when the pl011
driver probes, not when the console name is queried.  However, sbsa_probe()
is called before pl011_console_match().  The work-around appeared to work
previously because the default console on QDF2400 platforms was always
ttyAMA1.  The first time sbsa_probe() is called (for ttyAMA0),
qdf2400_e44_present is still false.  Then pl011_console_match() is called,
and it sets qdf2400_e44_present to true.  All subsequent calls to
sbsa_probe() enable the work-around.

The solution is to move the global variable into spcr.c and let the
pl011 driver query it during probe time.  This works because all QDF2400
platforms require SPCR, so parse_spcr() will always be called.
pl011_console_match still checks for the "qdf2400_e44" console name,
but it doesn't do anything else special.

Fixes: 5a0722b8 ("tty: pl011: use "qdf2400_e44" as the earlycon name for QDF2400 E44")
Tested-by: NJeffrey Hugo <jhugo@codeaurora.org>
Signed-off-by: NTimur Tabi <timur@codeaurora.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

When an early demuxed packet reaches __udp6_lib_lookup_skb(), the
sk reference is retrieved and used, but the relevant reference
count is leaked and the socket destructor is never called.
Beyond leaking the sk memory, if there are pending UDP packets
in the receive queue, even the related accounted memory is leaked.

In the long run, this will cause persistent forward allocation errors
and no UDP skbs (both ipv4 and ipv6) will be able to reach the
user-space.

Fix this by explicitly accessing the early demux reference before
the lookup, and properly decreasing the socket reference count
after usage.

Also drop the skb_steal_sock() in __udp6_lib_lookup_skb(), and
the now obsoleted comment about "socket cache".

The newly added code is derived from the current ipv4 code for the
similar path.

v1 -> v2:
  fixed the __udp6_lib_rcv() return code for resubmission,
  as suggested by Eric
Reported-by: NSam Edwards <CFSworks@gmail.com>
Reported-by: NMarc Haber <mh+netdev@zugschlus.de>
Fixes: 5425077d ("net: ipv6: Add early demux handler for UDP unicast")
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In order to mark relevant fields while setting the MTPPS register
add field select. Otherwise it can cause a misconfiguration in
firmware.

Fixes: ee7f1220 ('net/mlx5e: Implement 1PPS support')
Signed-off-by: NEugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

Fix miscalculation in reserved_at_1a0 field.

Fixes: ee7f1220 ('net/mlx5e: Implement 1PPS support')
Signed-off-by: NEugenia Emantayev <eugenia@mellanox.com>
Signed-off-by: NSaeed Mahameed <saeedm@mellanox.com>

That commit was part of the changes moving x86 to the generic CPU hotplug
interrupt migration code. The force flag was required on x86 before the
hierarchical irqdomain rework, but invoking set_affinity() with force=true
stayed and had no side effects.

At some point in the past, the force flag got repurposed to support the
exynos timer interrupt affinity setting to a not yet online CPU, so the
interrupt controller callback does not verify the supplied affinity mask
against cpu_online_mask.

Setting the flag in the CPU hotplug code causes the cpu online masking to
be blocked on these irq controllers and results in potentially affining an
interrupt to the CPU which is unplugged, i.e. instead of moving it away,
it's just reassigned to it.

As the force flags is not longer needed on x86, it's safe to revert that
patch so the ARM irqchips which use the force flag work again.

Add comments to that effect, so this won't happen again.

Note: The online mask handling should be done in the generic code and the
force flag and the masking in the irq chips removed all together, but
that's not a change possible for 4.13. 

Fixes: 77f85e66 ("genirq/cpuhotplug: Set force affinity flag on hotplug migration")
Reported-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NWill Deacon <will.deacon@arm.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: LAK <linux-arm-kernel@lists.infradead.org>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1707271217590.3109@nanosSigned-off-by: NThomas Gleixner <tglx@linutronix.de>

Since the PMU register interface is banked per CPU, CPU PMU interrrupts
cannot be handled by a CPU other than the one with the PMU asserting the
interrupt. This means that migrating PMU SPIs, as we do during a CPU
hotplug operation doesn't make any sense and can lead to the IRQ being
disabled entirely if we route a spurious IRQ to the new affinity target.

This has been observed in practice on AMD Seattle, where CPUs on the
non-boot cluster appear to take a spurious PMU IRQ when coming online,
which is routed to CPU0 where it cannot be handled.

This patch passes IRQF_PERCPU for PMU SPIs and forcefully sets their
affinity prior to requesting them, ensuring that they cannot
be migrated during hotplug events. This interacts badly with the DB8500
erratum workaround that ping-pongs the interrupt affinity from the handler,
so we avoid passing IRQF_PERCPU in that case by allowing the IRQ flags
to be overridden in the platdata.

Fixes: 3cf7ee98 ("drivers/perf: arm_pmu: move irq request/free into probe")
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: NWill Deacon <will.deacon@arm.com>

Commit b1f5bfc2 ("sctp: don't dereference ptr before leaving
_sctp_walk_{params, errors}()") tried to fix the issue that it
may overstep the chunk end for _sctp_walk_{params, errors} with
'chunk_end > offset(length) + sizeof(length)'.

But it introduced a side effect: When processing INIT, it verifies
the chunks with 'param.v == chunk_end' after iterating all params
by sctp_walk_params(). With the check 'chunk_end > offset(length)
+ sizeof(length)', it would return when the last param is not yet
accessed. Because the last param usually is fwdtsn supported param
whose size is 4 and 'chunk_end == offset(length) + sizeof(length)'

This is a badly issue even causing sctp couldn't process 4-shakes.
Client would always get abort when connecting to server, due to
the failure of INIT chunk verification on server.

The patch is to use 'chunk_end <= offset(length) + sizeof(length)'
instead of 'chunk_end < offset(length) + sizeof(length)' for both
_sctp_walk_params and _sctp_walk_errors.

Fixes: b1f5bfc2 ("sctp: don't dereference ptr before leaving _sctp_walk_{params, errors}()")
Signed-off-by: NXin Long <lucien.xin@gmail.com>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The CPU hotplug related code of this driver can be simplified by:

1) Consolidating the callbacks into a single state. The CPU thread can be
   torn down on the CPU which goes offline. There is no point in delaying
   that to the CPU dead state

2) Let the core code invoke the online/offline callbacks and remove the
   extra for_each_online_cpu() loops.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Acked-by: NChad Dupuis <chad.dupuis@cavium.com>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

The CPU hotplug related code of this driver can be simplified by:

1) Consolidating the callbacks into a single state. The CPU thread can be
   torn down on the CPU which goes offline. There is no point in delaying
   that to the CPU dead state

2) Let the core code invoke the online/offline callbacks and remove the
   extra for_each_online_cpu() loops.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NMartin K. Petersen <martin.petersen@oracle.com>

Currently dm_dax_flush() is not being called, even if underlying dax
device supports write cache, because DAXDEV_WRITE_CACHE is not being
propagated up to the DM dax device.

If the underlying dax device supports write cache, set
DAXDEV_WRITE_CACHE on the DM dax device.  This will cause dm_dax_flush()
to be called.

Fixes: abebfbe2 ("dm: add ->flush() dax operation support")
Signed-off-by: NVivek Goyal <vgoyal@redhat.com>
Acked-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NMike Snitzer <snitzer@redhat.com>

When CONFIG_EEH=y and CONFIG_VFIO_SPAPR_EEH=n, build fails with the
following:

    drivers/vfio/pci/vfio_pci.o: In function `.vfio_pci_release':
    vfio_pci.c:(.text+0xa98): undefined reference to `.vfio_spapr_pci_eeh_release'
    drivers/vfio/pci/vfio_pci.o: In function `.vfio_pci_open':
    vfio_pci.c:(.text+0x1420): undefined reference to `.vfio_spapr_pci_eeh_open'

In this case, vfio_pci.c should use the empty definitions of
vfio_spapr_pci_eeh_open and vfio_spapr_pci_eeh_release functions.

This patch fixes it by guarding these function definitions with
CONFIG_VFIO_SPAPR_EEH, the symbol that controls whether vfio_spapr_eeh.c is
built, which is where the non-empty versions of these functions are. We need to
make use of IS_ENABLED() macro because CONFIG_VFIO_SPAPR_EEH is a tristate
option.

This issue was found during a randconfig build. Logs are here:

    http://kisskb.ellerman.id.au/kisskb/buildresult/12982362/Signed-off-by: NMurilo Opsfelder Araujo <mopsfelder@gmail.com>
Reviewed-by: NAlexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: NDavid Gibson <david@gibson.dropbear.id.au>
Signed-off-by: NAlex Williamson <alex.williamson@redhat.com>

Simplify and improve the code so that the PID is always available in
the uevent even when debugfs is not available.

This adds a userspace_pid field to struct kvm, as per Radim's
suggestion, so that the PID can be retrieved on destruction too.
Acked-by: NJanosch Frank <frankja@linux.vnet.ibm.com>
Fixes: 286de8f6 ("KVM: trigger uevents when creating or destroying a VM")
Signed-off-by: NClaudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

drop VPFE_CMD_S_CCDC_RAW_PARAMS ioctl from dm355/dm644x following reasons:

- This ioctl was never in public api and was only defined in kernel header.
- The function set_params constantly mixes up pointers and phys_addr_t
  numbers.
- This is part of a 'VPFE_CMD_S_CCDC_RAW_PARAMS' ioctl command that is
  described as an 'experimental ioctl that will change in future kernels'.
- The code to allocate the table never gets called after we copy_from_user
  the user input over the kernel settings, and then compare them
  for inequality.
- We then go on to use an address provided by user space as both the
  __user pointer for input and pass it through phys_to_virt to come up
  with a kernel pointer to copy the data to. This looks like a trivially
  exploitable root hole.
Signed-off-by: NLad, Prabhakar <prabhakar.csengg@gmail.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>