syzbot reported the following error from a tree with a head commit of
baf76f0c ("slip: make slhc_free() silently accept an error pointer")

  BUG: unable to handle kernel paging request at ffffea0003348000
  #PF error: [normal kernel read fault]
  PGD 12c3f9067 P4D 12c3f9067 PUD 12c3f8067 PMD 0
  Oops: 0000 [#1] PREEMPT SMP KASAN
  CPU: 1 PID: 28916 Comm: syz-executor.2 Not tainted 5.1.0-rc6+ #89
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:314 [inline]
  RIP: 0010:PageCompound include/linux/page-flags.h:186 [inline]
  RIP: 0010:isolate_freepages_block+0x1c0/0xd40 mm/compaction.c:579
  Code: 01 d8 ff 4d 85 ed 0f 84 ef 07 00 00 e8 29 00 d8 ff 4c 89 e0 83 85 38 ff
  ff ff 01 48 c1 e8 03 42 80 3c 38 00 0f 85 31 0a 00 00 <4d> 8b 2c 24 31 ff 49
  c1 ed 10 41 83 e5 01 44 89 ee e8 3a 01 d8 ff
  RSP: 0018:ffff88802b31eab8 EFLAGS: 00010246
  RAX: 1ffffd4000669000 RBX: 00000000000cd200 RCX: ffffc9000a235000
  RDX: 000000000001ca5e RSI: ffffffff81988cc7 RDI: 0000000000000001
  RBP: ffff88802b31ebd8 R08: ffff88805af700c0 R09: 0000000000000000
  R10: 0000000000000000 R11: 0000000000000000 R12: ffffea0003348000
  R13: 0000000000000000 R14: ffff88802b31f030 R15: dffffc0000000000
  FS:  00007f61648dc700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: ffffea0003348000 CR3: 0000000037c64000 CR4: 00000000001426e0
  Call Trace:
   fast_isolate_around mm/compaction.c:1243 [inline]
   fast_isolate_freepages mm/compaction.c:1418 [inline]
   isolate_freepages mm/compaction.c:1438 [inline]
   compaction_alloc+0x1aee/0x22e0 mm/compaction.c:1550

There is no reproducer and it is difficult to hit -- 1 crash every few
days.  The issue is very similar to the fix in commit 6b0868c8
("mm/compaction.c: correct zone boundary handling when resetting pageblock
skip hints").  When isolating free pages around a target pageblock, the
boundary handling is off by one and can stray into the next pageblock.
Triggering the syzbot error requires that the end of pageblock is section
or zone aligned, and that the next section is unpopulated.

A more subtle consequence of the bug is that pageblocks were being
improperly used as migration targets which potentially hurts fragmentation
avoidance in the long-term one page at a time.

A debugging patch revealed that it's definitely possible to stray outside
of a pageblock which is not intended.  While syzbot cannot be used to
verify this patch, it was confirmed that the debugging warning no longer
triggers with this patch applied.  It has also been confirmed that the THP
allocation stress tests are not degraded by this patch.

Link: http://lkml.kernel.org/r/20190510182124.GI18914@techsingularity.net
Fixes: e332f741 ("mm, compaction: be selective about what pageblocks to clear skip hints")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: syzbot+d84c80f9fe26a0f7a734@syzkaller.appspotmail.com
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org> # v5.1+
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This macro adds some debug code to check that vmap allocations are
happened in ascending order.

By default this option is set to 0 and not active.  It requires
recompilation of the kernel to activate it.  Set to 1, compile the
kernel.

[urezki@gmail.com: v4]
  Link: http://lkml.kernel.org/r/20190406183508.25273-4-urezki@gmail.com
Link: http://lkml.kernel.org/r/20190402162531.10888-4-urezki@gmail.comSigned-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This macro adds some debug code to check that the augment tree is
maintained correctly, meaning that every node contains valid
subtree_max_size value.

By default this option is set to 0 and not active.  It requires
recompilation of the kernel to activate it.  Set to 1, compile the
kernel.

[urezki@gmail.com: v4]
  Link: http://lkml.kernel.org/r/20190406183508.25273-3-urezki@gmail.com
Link: http://lkml.kernel.org/r/20190402162531.10888-3-urezki@gmail.comSigned-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "improve vmap allocation", v3.

Objective
---------

Please have a look for the description at:

  https://lkml.org/lkml/2018/10/19/786

but let me also summarize it a bit here as well.

The current implementation has O(N) complexity. Requests with different
permissive parameters can lead to long allocation time. When i say
"long" i mean milliseconds.

Description
-----------

This approach organizes the KVA memory layout into free areas of the
1-ULONG_MAX range, i.e.  an allocation is done over free areas lookups,
instead of finding a hole between two busy blocks.  It allows to have
lower number of objects which represent the free space, therefore to have
less fragmented memory allocator.  Because free blocks are always as large
as possible.

It uses the augment tree where all free areas are sorted in ascending
order of va->va_start address in pair with linked list that provides
O(1) access to prev/next elements.

Since the tree is augment, we also maintain the "subtree_max_size" of VA
that reflects a maximum available free block in its left or right
sub-tree.  Knowing that, we can easily traversal toward the lowest (left
most path) free area.

Allocation: ~O(log(N)) complexity.  It is sequential allocation method
therefore tends to maximize locality.  The search is done until a first
suitable block is large enough to encompass the requested parameters.
Bigger areas are split.

I copy paste here the description of how the area is split, since i
described it in https://lkml.org/lkml/2018/10/19/786

<snip>

A free block can be split by three different ways.  Their names are
FL_FIT_TYPE, LE_FIT_TYPE/RE_FIT_TYPE and NE_FIT_TYPE, i.e.  they
correspond to how requested size and alignment fit to a free block.

FL_FIT_TYPE - in this case a free block is just removed from the free
list/tree because it fully fits.  Comparing with current design there is
an extra work with rb-tree updating.

LE_FIT_TYPE/RE_FIT_TYPE - left/right edges fit.  In this case what we do
is just cutting a free block.  It is as fast as a current design.  Most of
the vmalloc allocations just end up with this case, because the edge is
always aligned to 1.

NE_FIT_TYPE - Is much less common case.  Basically it happens when
requested size and alignment does not fit left nor right edges, i.e.  it
is between them.  In this case during splitting we have to build a
remaining left free area and place it back to the free list/tree.

Comparing with current design there are two extra steps.  First one is we
have to allocate a new vmap_area structure.  Second one we have to insert
that remaining free block to the address sorted list/tree.

In order to optimize a first case there is a cache with free_vmap objects.
Instead of allocating from slab we just take an object from the cache and
reuse it.

Second one is pretty optimized.  Since we know a start point in the tree
we do not do a search from the top.  Instead a traversal begins from a
rb-tree node we split.
<snip>

De-allocation.  ~O(log(N)) complexity.  An area is not inserted straight
away to the tree/list, instead we identify the spot first, checking if it
can be merged around neighbors.  The list provides O(1) access to
prev/next, so it is pretty fast to check it.  Summarizing.  If merged then
large coalesced areas are created, if not the area is just linked making
more fragments.

There is one more thing that i should mention here.  After modification of
VA node, its subtree_max_size is updated if it was/is the biggest area in
its left or right sub-tree.  Apart of that it can also be populated back
to upper levels to fix the tree.  For more details please have a look at
the __augment_tree_propagate_from() function and the description.

Tests and stressing
-------------------

I use the "test_vmalloc.sh" test driver available under
"tools/testing/selftests/vm/" since 5.1-rc1 kernel.  Just trigger "sudo
./test_vmalloc.sh" to find out how to deal with it.

Tested on different platforms including x86_64/i686/ARM64/x86_64_NUMA.
Regarding last one, i do not have any physical access to NUMA system,
therefore i emulated it.  The time of stressing is days.

If you run the test driver in "stress mode", you also need the patch that
is in Andrew's tree but not in Linux 5.1-rc1.  So, please apply it:

http://git.cmpxchg.org/cgit.cgi/linux-mmotm.git/commit/?id=e0cf7749bade6da318e98e934a24d8b62fab512c

After massive testing, i have not identified any problems like memory
leaks, crashes or kernel panics.  I find it stable, but more testing would
be good.

Performance analysis
--------------------

I have used two systems to test.  One is i5-3320M CPU @ 2.60GHz and
another is HiKey960(arm64) board.  i5-3320M runs on 4.20 kernel, whereas
Hikey960 uses 4.15 kernel.  I have both system which could run on 5.1-rc1
as well, but the results have not been ready by time i an writing this.

Currently it consist of 8 tests.  There are three of them which correspond
to different types of splitting(to compare with default).  We have 3
ones(see above).  Another 5 do allocations in different conditions.

a) sudo ./test_vmalloc.sh performance

When the test driver is run in "performance" mode, it runs all available
tests pinned to first online CPU with sequential execution test order.  We
do it in order to get stable and repeatable results.  Take a look at time
difference in "long_busy_list_alloc_test".  It is not surprising because
the worst case is O(N).

# i5-3320M
How many cycles all tests took:
CPU0=646919905370(default) cycles vs CPU0=193290498550(patched) cycles

# See detailed table with results here:
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_performance_default.txt
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_performance_patched.txt

# Hikey960 8x CPUs
How many cycles all tests took:
CPU0=3478683207 cycles vs CPU0=463767978 cycles

# See detailed table with results here:
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/HiKey960_performance_default.txt
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/HiKey960_performance_patched.txt

b) time sudo ./test_vmalloc.sh test_repeat_count=1

With this configuration, all tests are run on all available online CPUs.
Before running each CPU shuffles its tests execution order.  It gives
random allocation behaviour.  So it is rough comparison, but it puts in
the picture for sure.

# i5-3320M
<default>            vs            <patched>
real    101m22.813s                real    0m56.805s
user    0m0.011s                   user    0m0.015s
sys     0m5.076s                   sys     0m0.023s

# See detailed table with results here:
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_test_repeat_count_1_default.txt
ftp://vps418301.ovh.net/incoming/vmap_test_results_v2/i5-3320M_test_repeat_count_1_patched.txt

# Hikey960 8x CPUs
<default>            vs            <patched>
real    unknown                    real    4m25.214s
user    unknown                    user    0m0.011s
sys     unknown                    sys     0m0.670s

I did not manage to complete this test on "default Hikey960" kernel
version.  After 24 hours it was still running, therefore i had to cancel
it.  That is why real/user/sys are "unknown".

This patch (of 3):

Currently an allocation of the new vmap area is done over busy list
iteration(complexity O(n)) until a suitable hole is found between two busy
areas.  Therefore each new allocation causes the list being grown.  Due to
over fragmented list and different permissive parameters an allocation can
take a long time.  For example on embedded devices it is milliseconds.

This patch organizes the KVA memory layout into free areas of the
1-ULONG_MAX range.  It uses an augment red-black tree that keeps blocks
sorted by their offsets in pair with linked list keeping the free space in
order of increasing addresses.

Nodes are augmented with the size of the maximum available free block in
its left or right sub-tree.  Thus, that allows to take a decision and
traversal toward the block that will fit and will have the lowest start
address, i.e.  it is sequential allocation.

Allocation: to allocate a new block a search is done over the tree until a
suitable lowest(left most) block is large enough to encompass: the
requested size, alignment and vstart point.  If the block is bigger than
requested size - it is split.

De-allocation: when a busy vmap area is freed it can either be merged or
inserted to the tree.  Red-black tree allows efficiently find a spot
whereas a linked list provides a constant-time access to previous and next
blocks to check if merging can be done.  In case of merging of
de-allocated memory chunk a large coalesced area is created.

Complexity: ~O(log(N))

[urezki@gmail.com: v3]
  Link: http://lkml.kernel.org/r/20190402162531.10888-2-urezki@gmail.com
[urezki@gmail.com: v4]
  Link: http://lkml.kernel.org/r/20190406183508.25273-2-urezki@gmail.com
Link: http://lkml.kernel.org/r/20190321190327.11813-2-urezki@gmail.comSigned-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joel Fernandes <joelaf@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull KVM updates from Paolo Bonzini:
 "ARM:
   - support for SVE and Pointer Authentication in guests
   - PMU improvements

  POWER:
   - support for direct access to the POWER9 XIVE interrupt controller
   - memory and performance optimizations

  x86:
   - support for accessing memory not backed by struct page
   - fixes and refactoring

  Generic:
   - dirty page tracking improvements"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (155 commits)
  kvm: fix compilation on aarch64
  Revert "KVM: nVMX: Expose RDPMC-exiting only when guest supports PMU"
  kvm: x86: Fix L1TF mitigation for shadow MMU
  KVM: nVMX: Disable intercept for FS/GS base MSRs in vmcs02 when possible
  KVM: PPC: Book3S: Remove useless checks in 'release' method of KVM device
  KVM: PPC: Book3S HV: XIVE: Fix spelling mistake "acessing" -> "accessing"
  KVM: PPC: Book3S HV: Make sure to load LPID for radix VCPUs
  kvm: nVMX: Set nested_run_pending in vmx_set_nested_state after checks complete
  tests: kvm: Add tests for KVM_SET_NESTED_STATE
  KVM: nVMX: KVM_SET_NESTED_STATE - Tear down old EVMCS state before setting new state
  tests: kvm: Add tests for KVM_CAP_MAX_VCPUS and KVM_CAP_MAX_CPU_ID
  tests: kvm: Add tests to .gitignore
  KVM: Introduce KVM_CAP_MANUAL_DIRTY_LOG_PROTECT2
  KVM: Fix kvm_clear_dirty_log_protect off-by-(minus-)one
  KVM: Fix the bitmap range to copy during clear dirty
  KVM: arm64: Fix ptrauth ID register masking logic
  KVM: x86: use direct accessors for RIP and RSP
  KVM: VMX: Use accessors for GPRs outside of dedicated caching logic
  KVM: x86: Omit caching logic for always-available GPRs
  kvm, x86: Properly check whether a pfn is an MMIO or not
  ...

Merge tag 'nds32-for-linus-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux

Pull nds32 updates from Greentime Hu:

 - Clean up codes and Makefile

 - Fix a vDSO bug

 - Remove useless functions/header files

 - Update git repo path in MAINTAINERS

* tag 'nds32-for-linus-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/greentime/linux:
  nds32: Fix vDSO clock_getres()
  MAINTAINERS: update nds32 git repo path
  nds32: don't export low-level cache flushing routines
  arch: nds32: Kconfig: pedantic formatting
  nds32: fix semicolon code style issue
  nds32: vdso: drop unnecessary cc-ldoption
  nds32: remove unused generic-y += cmpxchg-local.h
  nds32: Use the correct style for SPDX License Identifier
  nds32: remove __virt_to_bus and __bus_to_virt
  nds32: vdso: fix and clean-up Makefile
  nds32: add vmlinux.lds and vdso.so to .gitignore
  nds32: ex-exit: Remove unneeded need_resched() loop
  nds32/io: Remove useless definition of mmiowb()
  nds32: Removed unused thread flag TIF_USEDFPU

Pull more s390 updates from Martin Schwidefsky:

 - Enhancements for the QDIO layer

 - Remove the RCP trace event

 - Avoid three build issues

 - Move the defconfig to the configs directory

* tag 's390-5.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390: move arch/s390/defconfig to arch/s390/configs/defconfig
  s390/qdio: optimize state inspection of HW-owned SBALs
  s390/qdio: use get_buf_state() in debug_get_buf_state()
  s390/qdio: allow to scan all Output SBALs in one go
  s390/cio: Remove tracing for rchp instruction
  s390/kasan: adapt disabled_wait usage to avoid build error
  latent_entropy: avoid build error when plugin cflags are not set
  s390/boot: fix compiler error due to missing awk strtonum

Pull more vfs mount updates from Al Viro:
 "Propagation of new syscalls to other architectures + cosmetic change
  from Christian (fscontext didn't follow the convention for anon inode
  names)"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  uapi: Wire up the mount API syscalls on non-x86 arches [ver #2]
  uapi, x86: Fix the syscall numbering of the mount API syscalls [ver #2]
  uapi, fsopen: use square brackets around "fscontext" [ver #2]

Commit e45adf66 ("KVM: Introduce a new guest mapping API", 2019-01-31)
introduced a build failure on aarch64 defconfig:

$ make -j$(nproc) ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- O=out defconfig \
                Image.gz
...
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:
    In function '__kvm_map_gfn':
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:1763:9: error:
    implicit declaration of function 'memremap'; did you mean 'memset_p'?
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:1763:46: error:
    'MEMREMAP_WB' undeclared (first use in this function)
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:
    In function 'kvm_vcpu_unmap':
../arch/arm64/kvm/../../../virt/kvm/kvm_main.c:1795:3: error:
    implicit declaration of function 'memunmap'; did you mean 'vm_munmap'?

because these functions are declared in <linux/io.h> rather than <asm/io.h>,
and the former was being pulled in already on x86 but not on aarch64.
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Pull io_uring fixes from Jens Axboe:
 "A small set of fixes for io_uring.

  This contains:

   - smp_rmb() cleanup for io_cqring_events() (Jackie)

   - io_cqring_wait() simplification (Jackie)

   - removal of dead 'ev_flags' passing (me)

   - SQ poll CPU affinity verification fix (me)

   - SQ poll wait fix (Roman)

   - SQE command prep cleanup and fix (Stefan)"

* tag 'for-linus-20190516' of git://git.kernel.dk/linux-block:
  io_uring: use wait_event_interruptible for cq_wait conditional wait
  io_uring: adjust smp_rmb inside io_cqring_events
  io_uring: fix infinite wait in khread_park() on io_finish_async()
  io_uring: remove 'ev_flags' argument
  io_uring: fix failure to verify SQ_AFF cpu
  io_uring: fix race condition reading SQE data

Pull more block updates from Jens Axboe:
 "This is mainly some late lightnvm changes that came in just before the
  merge window, as well as fixes that have been queued up since the
  initial pull request was frozen.

  This contains:

   - lightnvm changes, fixing race conditions, improving memory
     utilization, and improving pblk compatability (Chansol, Igor,
     Marcin)

   - NVMe pull request with minor fixes all over the map (via Christoph)

   - remove redundant error print in sata_rcar (Geert)

   - struct_size() cleanup (Jackie)

   - dasd CONFIG_LBADF warning fix (Ming)

   - brd cond_resched() improvement (Mikulas)"

* tag 'for-5.2/block-post-20190516' of git://git.kernel.dk/linux-block: (41 commits)
  block/bio-integrity: use struct_size() in kmalloc()
  nvme: validate cntlid during controller initialisation
  nvme: change locking for the per-subsystem controller list
  nvme: trace all async notice events
  nvme: fix typos in nvme status code values
  nvme-fabrics: remove unused argument
  nvme-multipath: avoid crash on invalid subsystem cntlid enumeration
  nvme-fc: use separate work queue to avoid warning
  nvme-rdma: remove redundant reference between ib_device and tagset
  nvme-pci: mark expected switch fall-through
  nvme-pci: add known admin effects to augument admin effects log page
  nvme-pci: init shadow doorbell after each reset
  brd: add cond_resched to brd_free_pages
  sata_rcar: Remove ata_host_alloc() error printing
  s390/dasd: fix build warning in dasd_eckd_build_cp_raw
  lightnvm: pblk: use nvm_rq_to_ppa_list()
  lightnvm: pblk: simplify partial read path
  lightnvm: do not remove instance under global lock
  lightnvm: track inflight target creations
  lightnvm: pblk: recover only written metadata
  ...

Pull more clk framework updates from Stephen Boyd:
 "One more patch to remove io.h from clk-provider.h.

  We used to need this include when we had clk_readl() and clk_writel(),
  but those are gone now so this patch pushes the dependency out to the
  users of clk-provider.h"

* tag 'clk-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: Remove io.h from clk-provider.h

Pull cgroup fix from Tejun Heo:
 "The cgroup2 freezer pulled in this cycle broke strace. This pull
  request includes a workaround for the problem.

  It's not a complete fix in that it may cause spurious frozen state
  flip-flops which is fairly minor. Will push a full fix once it's
  ready"

* 'for-5.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  signal: unconditionally leave the frozen state in ptrace_stop()

Merge tag 'linux-kselftest-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull more kselftest updates from Shuah Khan:

 - kselftest framework bpf build/test workflow regression fix

 - Fix to kselftest install to use default install path

 - Fix to kselftest KBUILD_OUTPUT builds to not clutter main
   KBUILD_OUTPUT directory with selftest objects

 - .gitignore fixes (Kelsey Skunberg)

 - rseq selftests updates (Mathieu Desnoyers and Martin Schwidefsky)

   They change the per-architecture pre-abort signatures to ensure those
   are valid trap instructions.

   The way exit points are presented to debuggers is enhanced, ensuring
   all exit points are present, so debuggers don't have to disassemble
   rseq critical section to properly skip over them.

   Discussions with the glibc community is reaching a consensus of
   exposing a __rseq_handled symbol from glibc to coexist with rseq
   early adopters. Update the rseq selftest code to expose and use this
   symbol.

   Support for compiling asm goto with clang is added with the
   "-no-integrated-as" compiler switch, similarly to the top level
   kernel Makefile.

 - kselftest Makefile test run output refactoring and making test output
   TAP13 compliant from Kees Cook:

   This re-factors the selftest Makefiles to extract the test running
   logic to be reused between "run_tests" and "emit_tests", while also
   fixing up the test output to be TAP version 13 compliant:
	- added "plan" line
	- fixed result line syntax
	- moved all test output to be "# "-prefixed as TAP "diagnostic"
	  lines

   The prefixing code includes a fallback mode for limited execution
   environments.

   Additionally, the plan lines are fixed for all callers of
   kselftest.h.

* tag 'linux-kselftest-5.2-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest: (25 commits)
  selftests: avoid KBUILD_OUTPUT dir cluttering with selftest objects
  selftests: drivers: Create .gitignore to include /dma-buf/udmabuf
  selftests: pidfd: Create .gitignore to include pidfd_test
  selftests: fix bpf build/test workflow regression when KBUILD_OUTPUT is set
  selftests: fix install target to use default install path
  rseq/selftests: add -no-integrated-as for clang
  rseq/selftests: mips: use break instruction for RSEQ_SIG
  rseq/selftests: powerpc code signature: generate valid instructions
  rseq/selftests: aarch64 code signature: handle big-endian environment
  rseq/selftests: arm: use udf instruction for RSEQ_SIG
  rseq/selftests: s390: use trap4 for RSEQ_SIG
  rseq/selftests: x86: use ud1 instruction as RSEQ_SIG opcode
  rseq/selftests: s390: use jg instruction for jumps outside of the asm
  rseq/selftests: Use __rseq_handled symbol to coexist with glibc
  rseq/selftests: Introduce __rseq_cs_ptr_array, rename __rseq_table to __rseq_cs
  rseq/selftests: Add __rseq_exit_point_array section for debuggers
  rseq/selftests: x86: Work-around bogus gcc-8 optimisation
  selftests: Add test plan API to kselftest.h and adjust callers
  selftests: Remove KSFT_TAP_LEVEL
  selftests: Move test output to diagnostic lines
  ...

Pull Devicetree vendor prefix conversion from Rob Herring:
 "Conversion of vendor-prefixes.txt to json-schema"

* tag 'devicetree-for-5.2-part2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  dt-bindings: Convert vendor prefixes to json-schema

Pull AFS callback promise fixes from David Howells:
 "This series fixes a bunch of problems in callback promise handling,
  where a callback promise indicates a promise on the part of the server
  to notify the client in the event of some sort of change to a file or
  volume. In the event of a break, the client has to go and refetch the
  client status from the server and discard any cached permission
  information as the ACL might have changed.

  The problem in the current code is that changes made by other clients
  aren't always noticed, primarily because the file status information
  and the callback information aren't updated in the same critical
  section, even if these are carried in the same reply from an RPC
  operation, and so the AFS_VNODE_CB_PROMISED flag is unreliable.

  Arranging for them to be done in the same critical section during
  reply decoding is tricky because of the FS.InlineBulkStatus op - which
  has all the statuses in the reply arriving and then all the callbacks,
  so they have to be buffered. It simplifies things a lot to move the
  critical section out of the decode phase and do it after the RPC
  function returns.

  Also new inodes (either newly fetched or newly created) aren't
  properly managed against a callback break happening before we get the
  local inode up and running.

  Fix this by:

   - There's now a combined file status and callback record (struct
     afs_status_cb) to carry both plus some flags.

   - Each operation wrapper function allocates sufficient afs_status_cb
     records for all the vnodes it is interested in and passes them into
     RPC operations to be filled in from the reply.

   - The FileStatus and CallBack record decoders no longer apply the
     new/revised status and callback information to the inode/vnode at
     the point of decoding and instead store the information into the
     record from (2).

   - afs_vnode_commit_status() then revises the file status, detects
     deletion and notes callback information inside of a single critical
     section. It also checks the callback break counters and cancels the
     callback promise if they changed during the operation.

     [*] Note that "callback break counters" are counters of server
     events that cancel one or more callback promises that the client
     thinks it has. The client counts the events and compares the
     counters before and after an operation to see if the callback
     promise it thinks it just got evaporated before it got recorded
     under lock.

   - Volume and server callback break counters are passed into
     afs_iget() allowing callback breaks concurrent with inode set up to
     be detected and the callback promise thence to be cancelled.

   - AFS validation checks are now done under RCU conditions using a
     read lock on cb_lock. This requires vnode->cb_interest to be made
     RCU safe.

   - If the checks in (6) fail, the callback breaker is then called
     under write lock on the cb_lock - but only if the callback break
     counter didn't change from the value read before the checks were
     made.

   - Results from FS.InlineBulkStatus that correspond to inodes we
     currently have in memory are now used to update those inodes'
     status and callback information rather than being discarded. This
     requires those inodes to be looked up before the RPC op is made and
     all their callback break values saved.

  To aid in this, the following changes have also been made:

   - Don't pass the vnode into the reply delivery functions or the
     decoders. The vnode shouldn't be altered anywhere in those paths.
     The only exception, for the moment, is for the call done hook for
     file lock ops that wants access to both the vnode and the call -
     this can be fixed at a later time.

   - Get rid of the call->reply[] void* array and replace it with named
     and typed members. This avoids confusion since different ops were
     mapping different reply[] members to different things.

   - Fix an order-1 kmalloc allocation in afs_do_lookup() and replace it
     with kvcalloc().

   - Always get the reply time. Since callback, lock and fileserver
     record expiry times are calculated for several RPCs, make this
     mandatory.

   - Call afs_pages_written_back() from the operation wrapper rather
     than from the delivery function.

   - Don't store the version and type from a callback promise in a reply
     as the information in them is of very limited use"

* tag 'afs-fixes-b-20190516' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Fix application of the results of a inline bulk status fetch
  afs: Pass pre-fetch server and volume break counts into afs_iget5_set()
  afs: Fix unlink to handle YFS.RemoveFile2 better
  afs: Clear AFS_VNODE_CB_PROMISED if we detect callback expiry
  afs: Make vnode->cb_interest RCU safe
  afs: Split afs_validate() so first part can be used under LOOKUP_RCU
  afs: Don't save callback version and type fields
  afs: Fix application of status and callback to be under same lock
  afs: Always get the reply time
  afs: Fix order-1 allocation in afs_do_lookup()
  afs: Get rid of afs_call::reply[]
  afs: Don't pass the vnode pointer through into the inline bulk status op

Pull misc AFS fixes from David Howells:
 "This fixes a set of miscellaneous issues in the afs filesystem,
  including:

   - leak of keys on file close.

   - broken error handling in xattr functions.

   - missing locking when updating VL server list.

   - volume location server DNS lookup whereby preloaded cells may not
     ever get a lookup and regular DNS lookups to maintain server lists
     consume power unnecessarily.

   - incorrect error propagation and handling in the fileserver
     iteration code causes operations to sometimes apparently succeed.

   - interruption of server record check/update side op during
     fileserver iteration causes uninterruptible main operations to fail
     unexpectedly.

   - callback promise expiry time miscalculation.

   - over invalidation of the callback promise on directories.

   - double locking on callback break waking up file locking waiters.

   - double increment of the vnode callback break counter.

  Note that it makes some changes outside of the afs code, including:

   - an extra parameter to dns_query() to allow the dns_resolver key
     just accessed to be immediately invalidated. AFS is caching the
     results itself, so the key can be discarded.

   - an interruptible version of wait_var_event().

   - an rxrpc function to allow the maximum lifespan to be set on a
     call.

   - a way for an rxrpc call to be marked as non-interruptible"

* tag 'afs-fixes-20190516' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  afs: Fix double inc of vnode->cb_break
  afs: Fix lock-wait/callback-break double locking
  afs: Don't invalidate callback if AFS_VNODE_DIR_VALID not set
  afs: Fix calculation of callback expiry time
  afs: Make dynamic root population wait uninterruptibly for proc_cells_lock
  afs: Make some RPC operations non-interruptible
  rxrpc: Allow the kernel to mark a call as being non-interruptible
  afs: Fix error propagation from server record check/update
  afs: Fix the maximum lifespan of VL and probe calls
  rxrpc: Provide kernel interface to set max lifespan on a call
  afs: Fix "kAFS: AFS vnode with undefined type 0"
  afs: Fix cell DNS lookup
  Add wait_var_event_interruptible()
  dns_resolver: Allow used keys to be invalidated
  afs: Fix afs_cell records to always have a VL server list record
  afs: Fix missing lock when replacing VL server list
  afs: Fix afs_xattr_get_yfs() to not try freeing an error value
  afs: Fix incorrect error handling in afs_xattr_get_acl()
  afs: Fix key leak in afs_release() and afs_evict_inode()

Pull ceph updates from Ilya Dryomov:
 "On the filesystem side we have:

   - a fix to enforce quotas set above the mount point (Luis Henriques)

   - support for exporting snapshots through NFS (Zheng Yan)

   - proper statx implementation (Jeff Layton). statx flags are mapped
     to MDS caps, with AT_STATX_{DONT,FORCE}_SYNC taken into account.

   - some follow-up dentry name handling fixes, in particular
     elimination of our hand-rolled helper and the switch to __getname()
     as suggested by Al (Jeff Layton)

   - a set of MDS client cleanups in preparation for async MDS requests
     in the future (Jeff Layton)

   - a fix to sync the filesystem before remounting (Jeff Layton)

  On the rbd side, work is on-going on object-map and fast-diff image
  features"

* tag 'ceph-for-5.2-rc1' of git://github.com/ceph/ceph-client: (29 commits)
  ceph: flush dirty inodes before proceeding with remount
  ceph: fix unaligned access in ceph_send_cap_releases
  libceph: make ceph_pr_addr take an struct ceph_entity_addr pointer
  libceph: fix unaligned accesses in ceph_entity_addr handling
  rbd: don't assert on writes to snapshots
  rbd: client_mutex is never nested
  ceph: print inode number in __caps_issued_mask debugging messages
  ceph: just call get_session in __ceph_lookup_mds_session
  ceph: simplify arguments and return semantics of try_get_cap_refs
  ceph: fix comment over ceph_drop_caps_for_unlink
  ceph: move wait for mds request into helper function
  ceph: have ceph_mdsc_do_request call ceph_mdsc_submit_request
  ceph: after an MDS request, do callback and completions
  ceph: use pathlen values returned by set_request_path_attr
  ceph: use __getname/__putname in ceph_mdsc_build_path
  ceph: use ceph_mdsc_build_path instead of clone_dentry_name
  ceph: fix potential use-after-free in ceph_mdsc_build_path
  ceph: dump granular cap info in "caps" debugfs file
  ceph: make iterate_session_caps a public symbol
  ceph: fix NULL pointer deref when debugging is enabled
  ...

Pull thermal management updates from Zhang Rui:

 - Remove the 'module' Kconfig option for thermal subsystem framework
   because the thermal framework are required to be ready as early as
   possible to avoid overheat at boot time (Daniel Lezcano)

 - Fix a bug that thermal framework pokes disabled thermal zones upon
   resume (Wei Wang)

  - A couple of cleanups and trivial fixes on int340x thermal drivers
    (Srinivas Pandruvada, Zhang Rui, Sumeet Pawnikar)

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux:
  drivers: thermal: processor_thermal: Downgrade error message
  mlxsw: Remove obsolete dependency on THERMAL=m
  hwmon/drivers/core: Simplify complex dependency
  thermal/drivers/core: Fix typo in the option name
  thermal/drivers/core: Remove depends on THERMAL in Kconfig
  thermal/drivers/core: Remove module unload code
  thermal/drivers/core: Remove the module Kconfig's option
  thermal: core: skip update disabled thermal zones after suspend
  thermal: make device_register's type argument const
  thermal: intel: int340x: processor_thermal_device: simplify to get driver data
  thermal/int3403_thermal: favor _TMP instead of PTYP

Merge tag 'for-5.2/dm-changes-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Improve DM snapshot target's scalability by using finer grained
   locking. Requires some list_bl interface improvements.

 - Add ability for DM integrity to use a bitmap mode, that tracks
   regions where data and metadata are out of sync, instead of using a
   journal.

 - Improve DM thin provisioning target to not write metadata changes to
   disk if the thin-pool and associated thin devices are merely
   activated but not used. This avoids metadata corruption due to
   concurrent activation of thin devices across different OS instances
   (e.g. split brain scenarios, which ultimately would be avoided if
   proper device filters were used -- but not having proper filtering
   has proven a very common configuration mistake)

 - Fix missing call to path selector type->end_io in DM multipath. This
   fixes reported performance problems due to inaccurate path selector
   IO accounting causing an imbalance of IO (e.g. avoiding issuing IO to
   particular path due to it seemingly being heavily used).

 - Fix bug in DM cache metadata's loading of its discard bitset that
   could lead to all cache blocks being discarded if the very first
   cache block was discarded (thankfully in practice the first cache
   block is generally in use; be it FS superblock, partition table, disk
   label, etc).

 - Add testing-only DM dust target which simulates a device that has
   failing sectors and/or read failures.

 - Fix a DM init error path reference count hang that caused boot hangs
   if user supplied malformed input on kernel commandline.

 - Fix a couple issues with DM crypt target's logging being overly
   verbose or lacking context.

 - Various other small fixes to DM init, DM multipath, DM zoned, and DM
   crypt.

* tag 'for-5.2/dm-changes-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (42 commits)
  dm: fix a couple brace coding style issues
  dm crypt: print device name in integrity error message
  dm crypt: move detailed message into debug level
  dm ioctl: fix hang in early create error condition
  dm integrity: whitespace, coding style and dead code cleanup
  dm integrity: implement synchronous mode for reboot handling
  dm integrity: handle machine reboot in bitmap mode
  dm integrity: add a bitmap mode
  dm integrity: introduce a function add_new_range_and_wait()
  dm integrity: allow large ranges to be described
  dm ingerity: pass size to dm_integrity_alloc_page_list()
  dm integrity: introduce rw_journal_sectors()
  dm integrity: update documentation
  dm integrity: don't report unused options
  dm integrity: don't check null pointer before kvfree and vfree
  dm integrity: correctly calculate the size of metadata area
  dm dust: Make dm_dust_init and dm_dust_exit static
  dm dust: remove redundant unsigned comparison to less than zero
  dm mpath: always free attached_handler_name in parse_path()
  dm init: fix max devices/targets checks
  ...

It turned out that DEBUG_SLAB_LEAK is still broken even after recent
recue efforts that when there is a large number of objects like
kmemleak_object which is normal on a debug kernel,

  # grep kmemleak /proc/slabinfo
  kmemleak_object   2243606 3436210 ...

reading /proc/slab_allocators could easily loop forever while processing
the kmemleak_object cache and any additional freeing or allocating
objects will trigger a reprocessing. To make a situation worse,
soft-lockups could easily happen in this sitatuion which will call
printk() to allocate more kmemleak objects to guarantee an infinite
loop.

Also, since it seems no one had noticed when it was totally broken
more than 2-year ago - see the commit fcf88917 ("slab: fix a crash
by reading /proc/slab_allocators"), probably nobody cares about it
anymore due to the decline of the SLAB. Just remove it entirely.
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Qian Cai <cai@lca.pw>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fix afs_do_lookup() such that when it does an inline bulk status fetch op,
it will update inodes that are already extant (something that afs_iget()
doesn't do) and to cache permits for each inode created (thereby avoiding a
follow up FS.FetchStatus call to determine this).

Extant inodes need looking up in advance so that their cb_break counters
before and after the operation can be compared.  To this end, the inode
pointers are cached so that they don't need looking up again after the op.

Fixes: 5cf9dd55 ("afs: Prospectively look up extra files when doing a single lookup")
Signed-off-by: David Howells <dhowells@redhat.com>

Pass the server and volume break counts from before the status fetch
operation that queried the attributes of a file into afs_iget5_set() so
that the new vnode's break counters can be initialised appropriately.

This allows detection of a volume or server break that happened whilst we
were fetching the status or setting up the vnode.

Fixes: c435ee34 ("afs: Overhaul the callback handling")
Signed-off-by: David Howells <dhowells@redhat.com>

Make use of the status update for the target file that the YFS.RemoveFile2
RPC op returns to correctly update the vnode as to whether the file was
actually deleted or just had nlink reduced.

Fixes: 30062bd1 ("afs: Implement YFS support in the fs client")
Signed-off-by: David Howells <dhowells@redhat.com>

Fix afs_validate() to clear AFS_VNODE_CB_PROMISED on a vnode if we detect
any condition that causes the callback promise to be broken implicitly,
including server break (cb_s_break), volume break (cb_v_break) or callback
expiry.

Fixes: ae3b7361 ("afs: Fix validation/callback interaction")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>

Use RCU-based freeing for afs_cb_interest struct objects and use RCU on
vnode->cb_interest.  Use that change to allow afs_check_validity() to use
read_seqbegin_or_lock() instead of read_seqlock_excl().

This also requires the caller of afs_check_validity() to hold the RCU read
lock across the call.
Signed-off-by: David Howells <dhowells@redhat.com>

Split afs_validate() so that the part that decides if the vnode is still
valid can be used under LOOKUP_RCU conditions from afs_d_revalidate().
Signed-off-by: David Howells <dhowells@redhat.com>

Don't save callback version and type fields as the version is about the
format of the callback information and the type is relative to the
particular RPC call.
Signed-off-by: David Howells <dhowells@redhat.com>

Convert the vendor prefix registry to a schema. This will enable checking
that new vendor prefixes are added (in addition to the less than perfect
checkpatch.pl check) and will also check against adding other prefixes
which are not vendors.

Converted vendor-prefixes.txt using the following sed script:

sed -e 's/\([a-zA-Z0-9\-]*\)[[:space:]]*\([a-zA-Z0-9].*\)/  "^\1,\.\*\":\n    description: \2/'
Signed-off-by: Rob Herring <robh@kernel.org>

Pull media fixes from Mauro Carvalho Chehab:
 "Some fixes for some platform drivers (rockchip, atmel, omap, daVinci,
  tegra-cec, coda and rcar).

  Also includes a fix on one of the V4L2 uAPI doc, explaining a border
  case"

* tag 'media/v5.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
  media: rockchip/vpu: Fix/re-order probe-error/remove path
  media: rockchip/vpu: Initialize mdev->bus_info
  media: rockchip/vpu: Get vdev from the file arg in vidioc_querycap()
  media: rockchip/vpu: Add missing dont_use_autosuspend() calls
  media: rockchip/vpu: Do not request id 0 for our video device
  media: tegra-cec: fix cec_notifier_parse_hdmi_phandle return check
  media: davinci/vpbe: array underflow in vpbe_enum_outputs()
  media: field-order.rst: clarify FIELD_ANY and FIELD_NONE
  media: staging/imx: add media device to capture register
  media: rcar-csi2: Propagate the FLD signal for NTSC and PAL
  media: rcar-csi2: restart CSI-2 link if error is detected
  media: omap_vout: potential buffer overflow in vidioc_dqbuf()
  media: coda: fix unset field and fail on invalid field in buf_prepare
  media: atmel: atmel-isc: fix asd memory allocation
  media: atmel: atmel-isc: fix INIT_WORK misplacement
  media: atmel: atmel-isc: limit incoming pixels per frame

Pull EDAC fixes from Borislav Petkov:

 - Do not build mpc85_edac as a module (Michael Ellerman)

 - Correct edac_mc_find()'s return value on error (Robert Richter)

* tag 'edac_fixes_for_5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp:
  EDAC/mc: Fix edac_mc_find() in case no device is found
  EDAC/mpc85xx: Prevent building as a module

Pull configfs update from Christoph Hellwig:

 - a fix for an error path use after free (YueHaibing)

* tag 'configfs-for-5.2' of git://git.infradead.org/users/hch/configfs:
  configfs: fix possible use-after-free in configfs_register_group

Pull nommu generic uaccess updates from Arnd Bergmann:
 "asm-generic: kill <asm/segment.h> and improve nommu generic uaccess helpers

  Christoph Hellwig writes:

     This is a series doing two somewhat interwinded things. It improves
     the asm-generic nommu uaccess helper to optionally be entirely
     generic and not require any arch helpers for the actual uaccess.
     For the generic uaccess.h to actually be generically useful I also
     had to kill off the mess we made of <asm/segment.h>, which really
     shouldn't exist on most architectures"

* tag 'asm-generic-nommu' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  asm-generic: optimize generic uaccess for 8-byte loads and stores
  asm-generic: provide entirely generic nommu uaccess
  arch: mostly remove <asm/segment.h>
  asm-generic: don't include <asm/segment.h> from <asm/uaccess.h>

Pull x86 fixes from Ingo Molnar:
 "Misc fixes and updates:

   - a handful of MDS documentation/comment updates

   - a cleanup related to hweight interfaces

   - a SEV guest fix for large pages

   - a kprobes LTO fix

   - and a final cleanup commit for vDSO HPET support removal"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/speculation/mds: Improve CPU buffer clear documentation
  x86/speculation/mds: Revert CPU buffer clear on double fault exit
  x86/kconfig: Disable CONFIG_GENERIC_HWEIGHT and remove __HAVE_ARCH_SW_HWEIGHT
  x86/mm: Do not use set_{pud, pmd}_safe() when splitting a large page
  x86/kprobes: Make trampoline_handler() global and visible
  x86/vdso: Remove hpet_page from vDSO

Pull time fixes from Ingo Molnar:
 "A TIA adjtimex interface extension, and a POSIX compliance ABI fix for
  timespec64 users"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  ntp: Allow TAI-UTC offset to be set to zero
  y2038: Make CONFIG_64BIT_TIME unconditional

Pull perf fixes from Ingo Molnar:
 "An x86 PMU constraint fix, an interface fix, and a Sparse fix"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86/intel: Allow PEBS multi-entry in watermark mode
  perf/x86/intel: Fix INTEL_FLAGS_EVENT_CONSTRAINT* masking
  perf/x86/amd/iommu: Make the 'amd_iommu_attr_groups' symbol static

Pull locking fix from Ingo Molnar:
 "A single rwsem fix"

* 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/rwsem: Prevent decrement of reader count before increment

Alex Xu reported a regression in strace, caused by the introduction of
the cgroup v2 freezer. The regression can be reproduced by stracing
the following simple program:

  #include <unistd.h>

  int main() {
      write(1, "a", 1);
      return 0;
  }

An attempt to run strace ./a.out leads to the infinite loop:
  [ pre-main omitted ]
  write(1, "a", 1)                        = ? ERESTARTSYS (To be restarted if SA_RESTART is set)
  write(1, "a", 1)                        = ? ERESTARTSYS (To be restarted if SA_RESTART is set)
  write(1, "a", 1)                        = ? ERESTARTSYS (To be restarted if SA_RESTART is set)
  write(1, "a", 1)                        = ? ERESTARTSYS (To be restarted if SA_RESTART is set)
  write(1, "a", 1)                        = ? ERESTARTSYS (To be restarted if SA_RESTART is set)
  write(1, "a", 1)                        = ? ERESTARTSYS (To be restarted if SA_RESTART is set)
  [ repeats forever ]

The problem occurs because the traced task leaves ptrace_stop()
(and the signal handling loop) with the frozen bit set. So let's
call cgroup_leave_frozen(true) unconditionally after sleeping
in ptrace_stop().

With this patch applied, strace works as expected:
  [ pre-main omitted ]
  write(1, "a", 1)                        = 1
  exit_group(0)                           = ?
  +++ exited with 0 +++
Reported-by: Alex Xu <alex_y_xu@yahoo.ca>
Fixes: 76f969e8 ("cgroup: cgroup v2 freezer")
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

Pull core fixes from Ingo Molnar:
 "A handful of objtool updates, plus a documentation addition for
  __ab_c_size()"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  objtool: Fix whitelist documentation typo
  objtool: Fix function fallthrough detection
  objtool: Don't use ignore flag for fake jumps
  overflow.h: Add comment documenting __ab_c_size()

Pull ARM updates from Russell King:
 "ARM development updates:

   - more unified assembly conversions for clang

   - drop obsolete -mauto-it assembler option

   - remove arm_memory_present in preference to the generic version

   - remove unused asm/limits.h header

   - vdso linker update

  We tried to make the assembler warn if unified syntax was not used,
  but unfortunately older versions of GCC warn, so the commit had to be
  reverted"

* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
  Revert "ARM: 8846/1: warn if divided syntax assembler is used"
  ARM: 8858/1: vdso: use $(LD) instead of $(CC) to link VDSO
  ARM: 8855/1: remove unused <asm/limits.h>
  ARM: 8850/1: use memblocks_present
  ARM: 8854/1: drop -mauto-it
  ARM: 8846/1: warn if divided syntax assembler is used
  ARM: 8853/1: drop WASM to work around LLVM issue
  ARM: 8852/1: uaccess: use unified assembler language syntax
  ARM: 8851/1: add TUSERCOND() macro for conditional postfix