We can move the INSN_LDI_R20 instruction into the branch delay slot.

Signed-off-by: Helge Deller <deller@gmx.de>

Add some additional checks to ensure the signal stack is inside
userspace bounds.

Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

As suggested by Arnd Bergmann, drop the parisc version of
strnlen_user() and switch to the generic version.

Suggested-by: Arnd Bergmann <arnd@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Helge Deller <deller@gmx.de>

Signed-off-by: Helge Deller <deller@gmx.de>

Merge yet more updates and hotfixes from Andrew Morton:
 "Post-linux-next material, based upon latest upstream to catch the
  now-merged dependencies:

   - 10 patches.

     Subsystems affected by this patch series: mm (vmstat and migration)
     and compat.

  And bunch of hotfixes, mostly cc:stable:

   - 8 patches.

     Subsystems affected by this patch series: mm (hmm, hugetlb, vmscan,
     pagealloc, pagemap, kmemleak, mempolicy, and memblock)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  arch: remove compat_alloc_user_space
  compat: remove some compat entry points
  mm: simplify compat numa syscalls
  mm: simplify compat_sys_move_pages
  kexec: avoid compat_alloc_user_space
  kexec: move locking into do_kexec_load
  mm: migrate: change to use bool type for 'page_was_mapped'
  mm: migrate: fix the incorrect function name in comments
  mm: migrate: introduce a local variable to get the number of pages
  mm/vmstat: protect per cpu variables with preempt disable on RT

* emailed hotfixes from Andrew Morton <akpm@linux-foundation.org>:
  nds32/setup: remove unused memblock_region variable in setup_memory()
  mm/mempolicy: fix a race between offset_il_node and mpol_rebind_task
  mm/kmemleak: allow __GFP_NOLOCKDEP passed to kmemleak's gfp
  mmap_lock: change trace and locking order
  mm/page_alloc.c: avoid accessing uninitialized pcp page migratetype
  mm,vmscan: fix divide by zero in get_scan_count
  mm/hugetlb: initialize hugetlb_usage in mm_init
  mm/hmm: bypass devmap pte when all pfn requested flags are fulfilled

kernel test robot reports unused variable warning:

   arch/nds32/kernel/setup.c:247:26: warning: Unused variable: region
   [unusedVariable]
    struct memblock_region *region;
                            ^

Remove the unused variable.

Link: https://lkml.kernel.org/r/20210712125218.28951-1-rppt@kernel.org


Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Vincent Chen <deanbo422@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Servers happened below panic:

  Kernel version:5.4.56
  BUG: unable to handle page fault for address: 0000000000002c48
  RIP: 0010:__next_zones_zonelist+0x1d/0x40
  Call Trace:
    __alloc_pages_nodemask+0x277/0x310
    alloc_page_interleave+0x13/0x70
    handle_mm_fault+0xf99/0x1390
    __do_page_fault+0x288/0x500
    do_page_fault+0x30/0x110
    page_fault+0x3e/0x50

The reason for the panic is that MAX_NUMNODES is passed in the third
parameter in __alloc_pages_nodemask(preferred_nid).  So access to
zonelist->zoneref->zone_idx in __next_zones_zonelist will cause a panic.

In offset_il_node(), first_node() returns nid from pol->v.nodes, after
this other threads may chang pol->v.nodes before next_node().  This race
condition will let next_node return MAX_NUMNODES.  So put pol->nodes in
a local variable.

The race condition is between offset_il_node and cpuset_change_task_nodemask:

  CPU0:                                     CPU1:
  alloc_pages_vma()
    interleave_nid(pol,)
      offset_il_node(pol,)
        first_node(pol->v.nodes)            cpuset_change_task_nodemask
                        //nodes==0xc          mpol_rebind_task
                                                mpol_rebind_policy
                                                  mpol_rebind_nodemask(pol,nodes)
                        //nodes==0x3
        next_node(nid, pol->v.nodes)//return MAX_NUMNODES

Link: https://lkml.kernel.org/r/20210906034658.48721-1-yanghui.def@bytedance.com


Signed-off-by: yanghui <yanghui.def@bytedance.com>
Reviewed-by: Muchun Song <songmuchun@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In a memory pressure situation, I'm seeing the lockdep WARNING below.
Actually, this is similar to a known false positive which is already
addressed by commit 6dcde60e ("xfs: more lockdep whackamole with
kmem_alloc*").

This warning still persists because it's not from kmalloc() itself but
from an allocation for kmemleak object.  While kmalloc() itself suppress
the warning with __GFP_NOLOCKDEP, gfp_kmemleak_mask() is dropping the
flag for the kmemleak's allocation.

Allow __GFP_NOLOCKDEP to be passed to kmemleak's allocation, so that the
warning for it is also suppressed.

  ======================================================
  WARNING: possible circular locking dependency detected
  5.14.0-rc7-BTRFS-ZNS+ #37 Not tainted
  ------------------------------------------------------
  kswapd0/288 is trying to acquire lock:
  ffff88825ab45df0 (&xfs_nondir_ilock_class){++++}-{3:3}, at: xfs_ilock+0x8a/0x250

  but task is already holding lock:
  ff...

Print to the trace log before releasing the lock to avoid racing with
other trace log printers of the same lock type.

Link: https://lkml.kernel.org/r/20210903022041.1843024-1-Liam.Howlett@oracle.com


Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michel Lespinasse <walken.cr@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If it's not prepared to free unref page, the pcp page migratetype is
unset.  Thus we will get rubbish from get_pcppage_migratetype() and
might list_del(&page->lru) again after it's already deleted from the list
leading to grumble about data corruption.

Link: https://lkml.kernel.org/r/20210902115447.57050-1-linmiaohe@huawei.com
Fixes: df1acc85

 ("mm/page_alloc: avoid conflating IRQs disabled with zone->lock")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit f56ce412 ("mm: memcontrol: fix occasional OOMs due to
proportional memory.low reclaim") introduced a divide by zero corner
case when oomd is being used in combination with cgroup memory.low
protection.

When oomd decides to kill a cgroup, it will force the cgroup memory to
be reclaimed after killing the tasks, by writing to the memory.max file
for that cgroup, forcing the remaining page cache and reclaimable slab
to be reclaimed down to zero.

Previously, on cgroups with some memory.low protection that would result
in the memory being reclaimed down to the memory.low limit, or likely
not at all, having the page cache reclaimed asynchronously later.

With f56ce412 the oomd write to memory.max tries to reclaim all the
way down to zero, which may race with another reclaimer, to the point of
ending up with the divide by zero below.

This patch implements the obvious fix.

Link: https://lkml.kernel.org/r/20210826220149.058089c6@imladris.surriel.com
Fixes: f56ce412

 ("mm: memcontrol: fix occasional OOMs due to proportional memory.low reclaim")
Signed-off-by: Rik van Riel <riel@surriel.com>
Acked-by: Roman Gushchin <guro@fb.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Chris Down <chris@chrisdown.name>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

After fork, the child process will get incorrect (2x) hugetlb_usage.  If
a process uses 5 2MB hugetlb pages in an anonymous mapping,

	HugetlbPages:	   10240 kB

and then forks, the child will show,

	HugetlbPages:	   20480 kB

The reason for double the amount is because hugetlb_usage will be copied
from the parent and then increased when we copy page tables from parent
to child.  Child will have 2x actual usage.

Fix this by adding hugetlb_count_init in mm_init.

Link: https://lkml.kernel.org/r/20210826071742.877-1-liuzixian4@huawei.com
Fixes: 5d317b2b

 ("mm: hugetlb: proc: add HugetlbPages field to /proc/PID/status")
Signed-off-by: Liu Zixian <liuzixian4@huawei.com>
Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Previously, we noticed the one rpma example was failed[1] since commit
36f30e48 ("IB/core: Improve ODP to use hmm_range_fault()"), where it
will use ODP feature to do RDMA WRITE between fsdax files.

After digging into the code, we found hmm_vma_handle_pte() will still
return EFAULT even though all the its requesting flags has been
fulfilled.  That's because a DAX page will be marked as (_PAGE_SPECIAL |
PAGE_DEVMAP) by pte_mkdevmap().

Link: https://github.com/pmem/rpma/issues/1142 [1]
Link: https://lkml.kernel.org/r/20210830094232.203029-1-lizhijian@cn.fujitsu.com
Fixes: 40550627

 ("mm/hmm: add missing call to hmm_pte_need_fault in HMM_PFN_SPECIAL handling")
Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-f...>

Merge tag 'tag-chrome-platform-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux

Pull chrome platform updates from Benson Leung:
 "cros_ec_typec:

   - make the cros_ec_typec driver to use the pre-existing
     cros_ec_check_features() function

  sensorhub:

   - add trace events for sample

  misc:

   - cros_ec_proto - re-send commands in the event of a timeout (for the
     FPMCU)

   - fix warnings in cros_ec_trace related to format output"

* tag 'tag-chrome-platform-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux:
  platform/chrome: cros_ec_trace: Fix format warnings
  platform/chrome: cros_ec_typec: Use existing feature check
  platform/chrome: cros_ec_proto: Send command again when timeout occurs
  platform/chrome: sensorhub: Add trace events for sample

Pull more power management updates from Rafael Wysocki:
 "These are mostly ARM cpufreq driver updates, including one new
  MediaTek driver that has just passed all of the reviews, with the
  addition of a revert of a recent intel_pstate commit, some core
  cpufreq changes and a DT-related update of the operating performance
  points (OPP) support code.

  Specifics:

   - Add new cpufreq driver for the MediaTek MT6779 platform called
     mediatek-hw along with corresponding DT bindings (Hector.Yuan).

   - Add DCVS interrupt support to the qcom-cpufreq-hw driver (Thara
     Gopinath).

   - Make the qcom-cpufreq-hw driver set the dvfs_possible_from_any_cpu
     policy flag (Taniya Das).

   - Blocklist more Qualcomm platforms in cpufreq-dt-platdev (Bjorn
     Andersson).

   - Make the vexpress cpufreq driver set the CPUFREQ_IS_COOLING_DEV
     flag (Viresh Kumar).

   - Add new cpufreq driver callback to allow drivers to register with
     the Energy Model in a consistent way and make several drivers use
     it (Viresh Kumar).

   - Change the remaining users of the .ready() cpufreq driver callback
     to move the code from it elsewhere and drop it from the cpufreq
     core (Viresh Kumar).

   - Revert recent intel_pstate change adding HWP guaranteed performance
     change notification support to it that led to problems, because the
     notification in question is triggered prematurely on some systems
     (Rafael Wysocki).

   - Convert the OPP DT bindings to DT schema and clean them up while at
     it (Rob Herring)"

* tag 'pm-5.15-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (23 commits)
  Revert "cpufreq: intel_pstate: Process HWP Guaranteed change notification"
  cpufreq: mediatek-hw: Add support for CPUFREQ HW
  cpufreq: Add of_perf_domain_get_sharing_cpumask
  dt-bindings: cpufreq: add bindings for MediaTek cpufreq HW
  cpufreq: Remove ready() callback
  cpufreq: sh: Remove sh_cpufreq_cpu_ready()
  cpufreq: acpi: Remove acpi_cpufreq_cpu_ready()
  cpufreq: qcom-hw: Set dvfs_possible_from_any_cpu cpufreq driver flag
  cpufreq: blocklist more Qualcomm platforms in cpufreq-dt-platdev
  cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support
  cpufreq: scmi: Use .register_em() to register with energy model
  cpufreq: vexpress: Use .register_em() to register with energy model
  cpufreq: scpi: Use .register_em() to register with energy model
  dt-bindings: opp: Convert to DT schema
  dt-bindings: Clean-up OPP binding node names in examples
  ARM: dts: omap: Drop references to opp.txt
  cpufreq: qcom-cpufreq-hw: Use .register_em() to register with energy model
  cpufreq: omap: Use .register_em() to register with energy model
  cpufreq: mediatek: Use .register_em() to register with energy model
  cpufreq: imx6q: Use .register_em() to register with energy model
  ...

Pull more ACPI updates from Rafael Wysocki:
 "These add ACPI support to the PCI VMD driver, improve suspend-to-idle
  support for AMD platforms and update documentation.

  Specifics:

   - Add ACPI support to the PCI VMD driver (Rafael Wysocki)

   - Rearrange suspend-to-idle support code to reflect the platform
     firmware expectations on some AMD platforms (Mario Limonciello)

   - Make SSDT overlays documentation follow the code documented by it
     more closely (Andy Shevchenko)"

* tag 'acpi-5.15-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: PM: s2idle: Run both AMD and Microsoft methods if both are supported
  Documentation: ACPI: Align the SSDT overlays file with the code
  PCI: VMD: ACPI: Make ACPI companion lookup work for VMD bus

Pull more documentation updates from Jonathan Corbet:
 "Another collection of documentation patches, mostly fixes but also
  includes another set of traditional Chinese translations"

* tag 'docs-5.15-2' of git://git.lwn.net/linux:
  docs: pdfdocs: Fix typo in CJK-language specific font settings
  docs: kernel-hacking: Remove inappropriate text
  docs/zh_TW: add translations for zh_TW/filesystems
  docs/zh_TW: add translations for zh_TW/cpu-freq
  docs/zh_TW: add translations for zh_TW/arm64
  docs/zh_CN: Modify the translator tag and fix the wrong word
  Documentation/features/vm: correct huge-vmap APIs
  Documentation: block: blk-mq: Fix small typo in multi-queue docs
  Documentation: in_irq() cleanup
  Documentation: arm: marvell: Add 88F6825 model into list
  Documentation/process/maintainer-pgp-guide: Replace broken link to PGP path finder
  Documentation: locking: fix references
  Documentation: Update details of The Linux Kernel Module Programming Guide
  docs: x86: Remove obsolete information about x86_64 vmalloc() faulting
  Documentation/process/applying-patches: Activate linux-next man hyperlink

Pull module updates from Jessica Yu:
 "The only main change I have for this round of updates is the modules
  MAINTAINERS update.

  As I find myself with less time to devote to upstream these days, Luis
  has kindly agreed to help maintain the module loader, to eventually
  transition to being the primary maintainer. Since Luis is already very
  involved upstream with experience maintaining various areas of the
  kernel including the kmod usermode helper, I think he is a great fit
  for this area of the kernel.

  Summary:

   - Add Luis Chamberlain as modules maintainer

   - Fix for .ctors sections in module linker script"

* tag 'modules-for-v5.15' of git://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux:
  MAINTAINERS: Add Luis Chamberlain as modules maintainer
  module: combine constructors in module linker script

Pull microblaze update from Michal Simek:

 - Kbuild clean up

* tag 'microblaze-v5.15' of git://git.monstr.eu/linux-2.6-microblaze:
  microblaze: move core-y in arch/microblaze/Makefile to arch/microblaze/Kbuild

Pull nfsd fixes from Chuck Lever:

 - Restore performance on memory-starved servers

* tag 'nfsd-5.15-1' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
  SUNRPC: improve error response to over-size gss credential
  SUNRPC: don't pause on incomplete allocation

Pull ceph updates from Ilya Dryomov:

 - a set of patches to address fsync stalls caused by depending on
   periodic rather than triggered MDS journal flushes in some cases
   (Xiubo Li)

 - a fix for mtime effectively not getting updated in case of competing
   writers (Jeff Layton)

 - a couple of fixes for inode reference leaks and various WARNs after
   "umount -f" (Xiubo Li)

 - a new ceph.auth_mds extended attribute (Jeff Layton)

 - a smattering of fixups and cleanups from Jeff, Xiubo and Colin.

* tag 'ceph-for-5.15-rc1' of git://github.com/ceph/ceph-client:
  ceph: fix dereference of null pointer cf
  ceph: drop the mdsc_get_session/put_session dout messages
  ceph: lockdep annotations for try_nonblocking_invalidate
  ceph: don't WARN if we're forcibly removing the session caps
  ceph: don't WARN if we're force umounting
  ceph: remove the capsnaps when removing caps
  ceph: request Fw caps before updating the mtime in ceph_write_iter
  ceph: reconnect to the export targets on new mdsmaps
  ceph: print more information when we can't find snaprealm
  ceph: add ceph_change_snap_realm() helper
  ceph: remove redundant initializations from mdsc and session
  ceph: cancel delayed work instead of flushing on mdsc teardown
  ceph: add a new vxattr to return auth mds for an inode
  ceph: remove some defunct forward declarations
  ceph: flush the mdlog before waiting on unsafe reqs
  ceph: flush mdlog before umounting
  ceph: make iterate_sessions a global symbol
  ceph: make ceph_create_session_msg a global symbol
  ceph: fix comment about short copies in ceph_write_end
  ceph: fix memory leak on decode error in ceph_handle_caps

Pull 9p updates from Dominique Martinet:
 "A couple of harmless fixes, increase max tcp msize (64KB -> 1MB), and
  increase default msize (8KB -> 128KB)

  The default increase has been discussed with Christian for the qemu
  side of things but makes sense for all supported transports"

* tag '9p-for-5.15-rc1' of git://github.com/martinetd/linux:
  net/9p: increase default msize to 128k
  net/9p: use macro to define default msize
  net/9p: increase tcp max msize to 1MB
  9p/xen: Fix end of loop tests for list_for_each_entry
  9p/trans_virtio: Remove sysfs file on probe failure

All users of compat_alloc_user_space() and copy_in_user() have been
removed from the kernel, only a few functions in sparc remain that can be
changed to calling arch_copy_in_user() instead.

Link: https://lkml.kernel.org/r/20210727144859.4150043-7-arnd@kernel.org


Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

These are all handled correctly when calling the native system call entry
point, so remove the special cases.

Link: https://lkml.kernel.org/r/20210727144859.4150043-6-arnd@kernel.org


Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The compat implementations for mbind, get_mempolicy, set_mempolicy and
migrate_pages are just there to handle the subtly different layout of
bitmaps on 32-bit hosts.

The compat implementation however lacks some of the checks that are
present in the native one, in particular for checking that the extra bits
are all zero when user space has a larger mask size than the kernel.
Worse, those extra bits do not get cleared when copying in or out of the
kernel, which can lead to incorrect data as well.

Unify the implementation to handle the compat bitmap layout directly in
the get_nodes() and copy_nodes_to_user() helpers.  Splitting out the
get_bitmap() helper from get_nodes() also helps readability of the native
case.

On x86, two additional problems are addressed by this: compat tasks can
pass a bitmap at the end of a mapping, causing a fault when reading across
the page boundary for a 64-bit word.  x32 tasks might also run into
problems with get_mempolicy corrupting data when an odd number of 32-bit
words gets passed.

On parisc the migrate_pages() system call apparently had the wrong calling
convention, as big-endian architectures expect the words inside of a
bitmap to be swapped.  This is not a problem though since parisc has no
NUMA support.

[arnd@arndb.de: fix mempolicy crash]
  Link: https://lkml.kernel.org/r/20210730143417.3700653-1-arnd@kernel.org
  Link: https://lore.kernel.org/lkml/YQPLG20V3dmOfq3a@osiris/

Link: https://lkml.kernel.org/r/20210727144859.4150043-5-arnd@kernel.org


Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The compat move_pages() implementation uses compat_alloc_user_space() for
converting the pointer array.  Moving the compat handling into the
function itself is a bit simpler and lets us avoid the
compat_alloc_user_space() call.

Link: https://lkml.kernel.org/r/20210727144859.4150043-4-arnd@kernel.org


Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kimage_alloc_init() expects a __user pointer, so compat_sys_kexec_load()
uses compat_alloc_user_space() to convert the layout and put it back onto
the user space caller stack.

Moving the user space access into the syscall handler directly actually
makes the code simpler, as the conversion for compat mode can now be done
on kernel memory.

Link: https://lkml.kernel.org/r/20210727144859.4150043-3-arnd@kernel.org
Link: https://lore.kernel.org/lkml/YPbtsU4GX6PL7%2F42@infradead.org/
Link: https://lore.kernel.org/lkml/m1y2cbzmnw.fsf@fess.ebiederm.org/


Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Co-developed-by: Eric Biederman <ebiederm@xmission.com>
Co-developed-by: Christoph Hellwig <hch@infradead.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "compat: remove compat_alloc_user_space", v5.

Going through compat_alloc_user_space() to convert indirect system call
arguments tends to add complexity compared to handling the native and
compat logic in the same code.

This patch (of 6):

The locking is the same between the native and compat version of
sys_kexec_load(), so it can be done in the common implementation to reduce
duplication.

Link: https://lkml.kernel.org/r/20210727144859.4150043-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20210727144859.4150043-2-arnd@kernel.org


Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Co-developed-by: Eric Biederman <ebiederm@xmission.com>
Co-developed-by: Christoph Hellwig <hch@infradead.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Feng Tang <feng.tang@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change to use bool type for 'page_was_mapped' variable making it more
readable.

Link: https://lkml.kernel.org/r/ce1279df18d2c163998c403e0b5ec6d3f6f90f7a.1629447552.git.baolin.wang@linux.alibaba.com


Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

since commit a98a2f0c ("mm/rmap: split migration into its own
function"), the migration ptes establishment has been split into a
separate try_to_migrate() function, thus update the related comments.

Link: https://lkml.kernel.org/r/5b824bad6183259c916ae6cf42f81d14c6118b06.1629447552.git.baolin.wang@linux.alibaba.com


Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Use thp_nr_pages() instead of compound_nr() to get the number of pages for
THP page, meanwhile introducing a local variable 'nr_pages' to avoid
getting the number of pages repeatedly.

Link: https://lkml.kernel.org/r/a8e331ac04392ee230c79186330fb05e86a2aa77.1629447552.git.baolin.wang@linux.alibaba.com


Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Disable preemption on -RT for the vmstat code.  On vanila the code runs in
IRQ-off regions while on -RT it may not when stats are updated under a
local_lock.  "preempt_disable" ensures that the same resources is not
updated in parallel due to preemption.

This patch differs from the preempt-rt version where __count_vm_event and
__count_vm_events are also protected.  The counters are explicitly
"allowed to be to be racy" so there is no need to protect them from
preemption.  Only the accurate page stats that are updated by a
read-modify-write need protection.  This patch also differs in that a
preempt_[en|dis]able_rt helper is not used.  As vmstat is the only user of
the helper, it was suggested that it be open-coded in vmstat.c instead of
risking the helper being used in unnecessary contexts.

Link: https://lkml.kernel.org/r/20210805160019.1137-2-mgorman@techsingularity.net


Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge more updates from Andrew Morton:
 "147 patches, based on 7d2a07b7.

  Subsystems affected by this patch series: mm (memory-hotplug, rmap,
  ioremap, highmem, cleanups, secretmem, kfence, damon, and vmscan),
  alpha, percpu, procfs, misc, core-kernel, MAINTAINERS, lib,
  checkpatch, epoll, init, nilfs2, coredump, fork, pids, criu, kconfig,
  selftests, ipc, and scripts"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (94 commits)
  scripts: check_extable: fix typo in user error message
  mm/workingset: correct kernel-doc notations
  ipc: replace costly bailout check in sysvipc_find_ipc()
  selftests/memfd: remove unused variable
  Kconfig.debug: drop selecting non-existing HARDLOCKUP_DETECTOR_ARCH
  configs: remove the obsolete CONFIG_INPUT_POLLDEV
  prctl: allow to setup brk for et_dyn executables
  pid: cleanup the stale comment mentioning pidmap_init().
  kernel/fork.c: unexport get_{mm,task}_exe_file
  coredump: fix memleak in dump_vma_snapshot()
  fs/coredump.c: log if a core dump is aborted due to changed file permissions
  nilfs2: use refcount_dec_and_lock() to fix potential UAF
  nilfs2: fix memory leak in nilfs_sysfs_delete_snapshot_group
  nilfs2: fix memory leak in nilfs_sysfs_create_snapshot_group
  nilfs2: fix memory leak in nilfs_sysfs_delete_##name##_group
  nilfs2: fix memory leak in nilfs_sysfs_create_##name##_group
  nilfs2: fix NULL pointer in nilfs_##name##_attr_release
  nilfs2: fix memory leak in nilfs_sysfs_create_device_group
  trap: cleanup trap_init()
  init: move usermodehelper_enable() to populate_rootfs()
  ...

Pull SLUB updates from Vlastimil Babka:
 "SLUB: reduce irq disabled scope and make it RT compatible

  This series was initially inspired by Mel's pcplist local_lock
  rewrite, and also interest to better understand SLUB's locking and the
  new primitives and RT variants and implications. It makes SLUB
  compatible with PREEMPT_RT and generally more preemption-friendly,
  apparently without significant regressions, as the fast paths are not
  affected.

  The main changes to SLUB by this series:

   - irq disabling is now only done for minimum amount of time needed to
     protect the strict kmem_cache_cpu fields, and as part of spin lock,
     local lock and bit lock operations to make them irq-safe

   - SLUB is fully PREEMPT_RT compatible

  The series should now be sufficiently tested in both RT and !RT
  configs, mainly thanks to Mike.

  The RFC/v1 version also got basic performance screening by Mel that
  didn't show major regressions. Mike's testing with hackbench of v2 on
  !RT reported negligible differences [6]:

    virgin(ish) tip
    5.13.0.g60ab3ed-tip
              7,320.67 msec task-clock                #    7.792 CPUs utilized            ( +-  0.31% )
               221,215      context-switches          #    0.030 M/sec                    ( +-  3.97% )
                16,234      cpu-migrations            #    0.002 M/sec                    ( +-  4.07% )
                13,233      page-faults               #    0.002 M/sec                    ( +-  0.91% )
        27,592,205,252      cycles                    #    3.769 GHz                      ( +-  0.32% )
         8,309,495,040      instructions              #    0.30  insn per cycle           ( +-  0.37% )
         1,555,210,607      branches                  #  212.441 M/sec                    ( +-  0.42% )
             5,484,209      branch-misses             #    0.35% of all branches          ( +-  2.13% )

               0.93949 +- 0.00423 seconds time elapsed  ( +-  0.45% )
               0.94608 +- 0.00384 seconds time elapsed  ( +-  0.41% ) (repeat)
               0.94422 +- 0.00410 seconds time elapsed  ( +-  0.43% )

    5.13.0.g60ab3ed-tip +slub-local-lock-v2r3
              7,343.57 msec task-clock                #    7.776 CPUs utilized            ( +-  0.44% )
               223,044      context-switches          #    0.030 M/sec                    ( +-  3.02% )
                16,057      cpu-migrations            #    0.002 M/sec                    ( +-  4.03% )
                13,164      page-faults               #    0.002 M/sec                    ( +-  0.97% )
        27,684,906,017      cycles                    #    3.770 GHz                      ( +-  0.45% )
         8,323,273,871      instructions              #    0.30  insn per cycle           ( +-  0.28% )
         1,556,106,680      branches                  #  211.901 M/sec                    ( +-  0.31% )
             5,463,468      branch-misses             #    0.35% of all branches          ( +-  1.33% )

               0.94440 +- 0.00352 seconds time elapsed  ( +-  0.37% )
               0.94830 +- 0.00228 seconds time elapsed  ( +-  0.24% ) (repeat)
               0.93813 +- 0.00440 seconds time elapsed  ( +-  0.47% ) (repeat)

  RT configs showed some throughput regressions, but that's expected
  tradeoff for the preemption improvements through the RT mutex. It
  didn't prevent the v2 to be incorporated to the 5.13 RT tree [7],
  leading to testing exposure and bugfixes.

  Before the series, SLUB is lockless in both allocation and free fast
  paths, but elsewhere, it's disabling irqs for considerable periods of
  time - especially in allocation slowpath and the bulk allocation,
  where IRQs are re-enabled only when a new page from the page allocator
  is needed, and the context allows blocking. The irq disabled sections
  can then include deactivate_slab() which walks a full freelist and
  frees the slab back to page allocator or unfreeze_partials() going
  through a list of percpu partial slabs. The RT tree currently has some
  patches mitigating these, but we can do much better in mainline too.

  Patches 1-6 are straightforward improvements or cleanups that could
  exist outside of this series too, but are prerequsities.

  Patches 7-9 are also preparatory code changes without functional
  changes, but not so useful without the rest of the series.

  Patch 10 simplifies the fast paths on systems with preemption, based
  on (hopefully correct) observation that the current loops to verify
  tid are unnecessary.

  Patches 11-20 focus on reducing irq disabled scope in the allocation
  slowpath:

   - patch 11 moves disabling of irqs into ___slab_alloc() from its
     callers, which are the allocation slowpath, and bulk allocation.
     Instead these callers only disable preemption to stabilize the cpu.

   - The following patches then gradually reduce the scope of disabled
     irqs in ___slab_alloc() and the functions called from there. As of
     patch 14, the re-enabling of irqs based on gfp flags before calling
     the page allocator is removed from allocate_slab(). As of patch 17,
     it's possible to reach the page allocator (in case of existing
     slabs depleted) without disabling and re-enabling irqs a single
     time.

  Pathces 21-26 reduce the scope of disabled irqs in functions related
  to unfreezing percpu partial slab.

  Patch 27 is preparatory. Patch 28 is adopted from the RT tree and
  converts the flushing of percpu slabs on all cpus from using IPI to
  workqueue, so that the processing isn't happening with irqs disabled
  in the IPI handler. The flushing is not performance critical so it
  should be acceptable.

  Patch 29 also comes from RT tree and makes object_map_lock RT
  compatible.

  Patch 30 make slab_lock irq-safe on RT where we cannot rely on having
  irq disabled from the list_lock spin lock usage.

  Patch 31 changes kmem_cache_cpu->partial handling in put_cpu_partial()
  from cmpxchg loop to a short irq disabled section, which is used by
  all other code modifying the field. This addresses a theoretical race
  scenario pointed out by Jann, and makes the critical section safe wrt
  with RT local_lock semantics after the conversion in patch 35.

  Patch 32 changes preempt disable to migrate disable, so that the
  nested list_lock spinlock is safe to take on RT. Because
  migrate_disable() is a function call even on !RT, a small set of
  private wrappers is introduced to keep using the cheaper
  preempt_disable() on !PREEMPT_RT configurations. As of this patch,
  SLUB should be already compatible with RT's lock semantics.

  Finally, patch 33 changes irq disabled sections that protect
  kmem_cache_cpu fields in the slow paths, with a local lock. However on
  PREEMPT_RT it means the lockless fast paths can now preempt slow paths
  which don't expect that, so the local lock has to be taken also in the
  fast paths and they are no longer lockless. RT folks seem to not mind
  this tradeoff. The patch also updates the locking documentation in the
  file's comment"

Mike Galbraith and Mel Gorman verified that their earlier testing
observations still hold for the final series:

Link: https://lore.kernel.org/lkml/89ba4f783114520c167cc915ba949ad2c04d6790.camel@gmx.de/
Link: https://lore.kernel.org/lkml/20210907082010.GB3959@techsingularity.net/

* tag 'mm-slub-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux: (33 commits)
  mm, slub: convert kmem_cpu_slab protection to local_lock
  mm, slub: use migrate_disable() on PREEMPT_RT
  mm, slub: protect put_cpu_partial() with disabled irqs instead of cmpxchg
  mm, slub: make slab_lock() disable irqs with PREEMPT_RT
  mm: slub: make object_map_lock a raw_spinlock_t
  mm: slub: move flush_cpu_slab() invocations __free_slab() invocations out of IRQ context
  mm, slab: split out the cpu offline variant of flush_slab()
  mm, slub: don't disable irqs in slub_cpu_dead()
  mm, slub: only disable irq with spin_lock in __unfreeze_partials()
  mm, slub: separate detaching of partial list in unfreeze_partials() from unfreezing
  mm, slub: detach whole partial list at once in unfreeze_partials()
  mm, slub: discard slabs in unfreeze_partials() without irqs disabled
  mm, slub: move irq control into unfreeze_partials()
  mm, slub: call deactivate_slab() without disabling irqs
  mm, slub: make locking in deactivate_slab() irq-safe
  mm, slub: move reset of c->page and freelist out of deactivate_slab()
  mm, slub: stop disabling irqs around get_partial()
  mm, slub: check new pages with restored irqs
  mm, slub: validate slab from partial list or page allocator before making it cpu slab
  mm, slub: restore irqs around calling new_slab()
  ...

Fix typo ("and" should be "an") in an error message.

Link: https://lkml.kernel.org/r/20210727002943.29774-1-rdunlap@infradead.org


Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Use the documented kernel-doc format to prevent kernel-doc warnings.

mm/workingset.c:256: warning: No description found for return value of 'workingset_eviction'
mm/workingset.c:285: warning: Function parameter or member 'folio' not described in 'workingset_refault'
mm/workingset.c:285: warning: Excess function parameter 'page' description in 'workingset_refault'

Link: https://lkml.kernel.org/r/20210808203153.10678-1-rdunlap@infradead.org


Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sysvipc_find_ipc() was left with a costly way to check if the offset
position fed to it is bigger than the total number of IPC IDs in use.  So
much so that the time it takes to iterate over /proc/sysvipc/* files grows
exponentially for a custom benchmark that creates "N" SYSV shm segments
and then times the read of /proc/sysvipc/shm (milliseconds):

    12 msecs to read   1024 segs from /proc/sysvipc/shm
    18 msecs to read   2048 segs from /proc/sysvipc/shm
    65 msecs to read   4096 segs from /proc/sysvipc/shm
   325 msecs to read   8192 segs from /proc/sysvipc/shm
  1303 msecs to read  16384 segs from /proc/sysvipc/shm
  5182 msecs to read  32768 segs from /proc/sysvipc/shm

The root problem lies with the loop that computes the total amount of ids
in use to check if the "pos" feeded to sysvipc_find_ipc() grew bigger than
"ids->in_use".  That is a quite inneficient way to get to the maximum
index in the id lookup table, specially when that value is already
provided by struct ipc_ids.max_idx.

This patch follows up on the optimization introduced via commit
15df03c8 ("sysvipc: make get_maxid O(1) again") and gets rid of the
aforementioned costly loop replacing it by a simpler checkpoint based on
ipc_get_maxidx() returned value, which allows for a smooth linear increase
in time complexity for the same custom benchmark:

     2 msecs to read   1024 segs from /proc/sysvipc/shm
     2 msecs to read   2048 segs from /proc/sysvipc/shm
     4 msecs to read   4096 segs from /proc/sysvipc/shm
     9 msecs to read   8192 segs from /proc/sysvipc/shm
    19 msecs to read  16384 segs from /proc/sysvipc/shm
    39 msecs to read  32768 segs from /proc/sysvipc/shm

Link: https://lkml.kernel.org/r/20210809203554.1562989-1-aquini@redhat.com


Signed-off-by: Rafael Aquini <aquini@redhat.com>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Cc: Waiman Long <llong@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 54402986 ("selftests/memfd: add tests for F_SEAL_FUTURE_WRITE
seal") added an unused variable to mfd_assert_reopen_fd().

Delete the unused variable.

Link: https://lkml.kernel.org/r/20210702045509.1517643-1-gthelen@google.com
Fixes: 54402986

 ("selftests/memfd: add tests for F_SEAL_FUTURE_WRITE seal")
Signed-off-by: Greg Thelen <gthelen@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: "Joel Fernandes (Google)" <joel@joelfernandes.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit 05a4a952 ("kernel/watchdog: split up config options") adds a
new config HARDLOCKUP_DETECTOR, which selects the non-existing config
HARDLOCKUP_DETECTOR_ARCH.

Hence, ./scripts/checkkconfigsymbols.py warns:

HARDLOCKUP_DETECTOR_ARCH Referencing files: lib/Kconfig.debug

Simply drop selecting the non-existing HARDLOCKUP_DETECTOR_ARCH.

Link: https://lkml.kernel.org/r/20210806115618.22088-1-lukas.bulwahn@gmail.com
Fixes: 05a4a952

 ("kernel/watchdog: split up config options")
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Masahiro Yamada <masahiroy@kernel.org>
Cc: Babu Moger <babu.moger@oracle.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>