Using a transaction in btrfs_search_slot is only useful when we are
searching to add or modify the tree. When the function is used for
searching, insert length and mod arguments are 0, there is no need to
use a transaction.

No functional changes, changing for consistency.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

At reada_for_search(), when attempting to readahead a node or leaf's
siblings, we skip the readahead of the siblings if the node/leaf is
already in memory. That is probably fine for the READA_FORWARD and
READA_BACK readahead types, as they are used on contexts where we
end up reading some consecutive leaves, but usually not the whole btree.

However for a READA_FORWARD_ALWAYS mode, currently only used for full
send operations, it does not make sense to skip the readahead if the
target node or leaf is already loaded in memory, since we know the caller
is visiting every node and leaf of the btree in ascending order.

So change the behaviour to not skip the readahead when the target node is
already in memory and the readahead mode is READA_FORWARD_ALWAYS.

The following test script was used to measure the improvement on a box
using an average, consumer grade, spinning disk, with 32GiB of RAM and
using a non-debug kernel config (Debian's default config).

  $ cat test.sh
  #!/bin/bash

  DEV=/dev/sdj
  MNT=/mnt/sdj
  MKFS_OPTIONS="--nodesize 16384"     # default, just to be explicit
  MOUNT_OPTIONS="-o max_inline=2048"  # default, just to be explicit

  mkfs.btrfs -f $MKFS_OPTIONS $DEV > /dev/null
  mount $MOUNT_OPTIONS $DEV $MNT

  # Create files with inline data to make it easier and faster to create
  # large btrees.
  add_files()
  {
      local total=$1
      local start_offset=$2
      local number_jobs=$3
      local total_per_job=$(($total / $number_jobs))

      echo "Creating $total new files using $number_jobs jobs"
      for ((n = 0; n < $number_jobs; n++)); do
          (
              local start_num=$(($start_offset + $n * $total_per_job))
              for ((i = 1; i <= $total_per_job; i++)); do
                  local file_num=$((start_num + $i))
                  local file_path="$MNT/file_${file_num}"
                  xfs_io -f -c "pwrite -S 0xab 0 2000" $file_path > /dev/null
                  if [ $? -ne 0 ]; then
                      echo "Failed creating file $file_path"
                      break
                  fi
              done
          ) &
          worker_pids[$n]=$!
      done

      wait ${worker_pids[@]}

      sync
      echo
      echo "btree node/leaf count: $(btrfs inspect-internal dump-tree -t 5 $DEV | egrep '^(node|leaf) ' | wc -l)"
  }

  file_count=2000000
  add_files $file_count 0 4

  echo
  echo "Creating snapshot..."
  btrfs subvolume snapshot -r $MNT $MNT/snap1

  umount $MNT

  echo 3 > /proc/sys/vm/drop_caches
  blockdev --flushbufs $DEV &> /dev/null
  hdparm -F $DEV &> /dev/null

  mount $MOUNT_OPTIONS $DEV $MNT

  echo
  echo "Testing full send..."
  start=$(date +%s)
  btrfs send $MNT/snap1 > /dev/null
  end=$(date +%s)
  echo
  echo "Full send took $((end - start)) seconds"

  umount $MNT

The duration of the full send operations, in seconds, were the following:

Before this change:  85 seconds
After this change:   76 seconds (-11.2%)
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The pages in block_ctx have never been allocated from highmem (in
btrfsic_read_block) so the mapping is pointless and can be removed.
Signed-off-by: David Sterba <dsterba@suse.com>

The pages in compressed_pages are not from highmem anymore so we can
drop the mapping for checksum calculation and inline extent.
Signed-off-by: David Sterba <dsterba@suse.com>

As we don't use highmem pages anymore, drop the kmap/kunmap. The kmap is
simply page_address and kunmap is a no-op.
Signed-off-by: David Sterba <dsterba@suse.com>

As we don't use highmem pages anymore, drop the kmap/kunmap. The kmap is
simply page_address and kunmap is a no-op.
Signed-off-by: David Sterba <dsterba@suse.com>

As we don't use highmem pages anymore, drop the kmap/kunmap. The kmap is
simply page_address and kunmap is a no-op.
Signed-off-by: David Sterba <dsterba@suse.com>

The highmem flag is used for allocating pages for compression and for
raid56 pages. The high memory makes sense on 32bit systems but is not
without problems. On 64bit system's it's just another layer of wrappers.

The time the pages are allocated for compression or raid56 is relatively
short (about a transaction commit), so the pages are not blocked
indefinitely. As the number of pages depends on the amount of data being
written/read, there's a theoretical problem. A fast device on a 32bit
system could use most of the low memory pool, while with the highmem
allocation that would not happen. This was possibly the original idea
long time ago, but nowadays we optimize for 64bit systems.

This patch removes all usage of the __GFP_HIGHMEM flag for page
allocation, the kmap/kunmap are still in place and will be removed in
followup patches. Remaining is masking out the bit in
alloc_extent_state and __lookup_free_space_inode, that can safely stay.
Signed-off-by: David Sterba <dsterba@suse.com>

Drop variable 'devices' (used only once) and add new variable for
the fs_devices, so it is used at two locations within btrfs_trim_fs()
function and also helps to access fs_devices->devices.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Both callers use btrfs_header_nritems to feed the max argument.  Remove
the argument and let generic_bin_search call it itself.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Marcos Paulo de Souza <mpdesouza@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

One of the final things that must be done to add a new chunk is
inserting its device extent items in the device tree. They describe
the portion of allocated device physical space during phase 1 of
chunk allocation. This is currently done in btrfs_finish_chunk_alloc
whose name isn't very informative. What's more, this function is only
used in block-group.c but is defined as public. There isn't anything
special about it that would warrant it being defined in volumes.c.

Just move btrfs_finish_chunk_alloc and alloc_chunk_dev_extent to
block-group.c, make the former static and rename both functions to
insert_dev_extents and insert_dev_extent respectively.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

The function prototypes below aren't necessary as the functions are
first defined before called. Remove them.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

On 64K pages the size of the extent_buffer::pages array is 1 and
compilation with -Warray-bounds warns due to

  kaddr = page_address(eb->pages[idx + 1]);

when reading byte range crossing page boundary.

This does never actually overflow the array because on 64K because all
the data fit in one page and bounds are checked by check_setget_bounds.

To fix the reported overflows and warnings add a compile-time condition
that will allow compiler to eliminate the dead code that reads from the
idx + 1 page.

Link: https://lore.kernel.org/lkml/20210623083901.1d49d19d@canb.auug.org.au/
CC: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: David Sterba <dsterba@suse.com>

There used to be a patch in the original series for zoned support which
limited the extent size to max_zone_append_size, but this patch has been
dropped somewhere around v9.

We've decided to go the opposite direction, instead of limiting extents
in the first place we split them before submission to comply with the
device's limits.

Remove the related code, btrfs_fs_info::max_zone_append_size and
btrfs_zoned_device_info::max_zone_append_size.

This also removes the workaround for dm-crypt introduced in
1d68128c ("btrfs: zoned: fail mount if the device does not support
zone append") because the fix has been merged as f34ee1dc ("dm
crypt: Fix zoned block device support").
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Pull powerpc fixes from Michael Ellerman:

 - Fix random crashes on some 32-bit CPUs by adding isync() after
   locking/unlocking KUEP

 - Fix intermittent crashes when loading modules with strict module RWX

 - Fix a section mismatch introduce by a previous fix.

Thanks to Christophe Leroy, Fabiano Rosas, Laurent Vivier, Murilo
Opsfelder Araújo, Nathan Chancellor, and Stan Johnson.

h# -----BEGIN PGP SIGNATURE-----

* tag 'powerpc-5.14-6' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/mm: Fix set_memory_*() against concurrent accesses
  powerpc/32s: Fix random crashes by adding isync() after locking/unlocking KUEP
  powerpc/xive: Do not mark xive_request_ipi() as __init

Pull clk driver fixes from Stephen Boyd:

 - Make the regulator state match the GDSC power domain state at boot on
   Qualcomm SoCs so that the regulator isn't turned off inadvertently.

 - Fix earlycon on i.MX6Q SoCs

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: qcom: gdsc: Ensure regulator init state matches GDSC state
  clk: imx6q: fix uart earlycon unwork

Pull char/misc driver fixes from Greg KH:
 "Here are some small driver fixes for 5.14-rc7.

  They consist of:

   - revert for an interconnect patch that was found to have problems

   - ipack tpci200 driver fixes for reported problems

   - slimbus messaging and ngd fixes for reported problems

  All are small and have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  ipack: tpci200: fix memory leak in the tpci200_register
  ipack: tpci200: fix many double free issues in tpci200_pci_probe
  slimbus: ngd: reset dma setup during runtime pm
  slimbus: ngd: set correct device for pm
  slimbus: messaging: check for valid transaction id
  slimbus: messaging: start transaction ids from 1 instead of zero
  Revert "interconnect: qcom: icc-rpmh: Add BCMs to commit list in pre_aggregate"

Pull USB fix from Greg KH:
 "Here is a single USB typec tcpm fix for a reported problem for
  5.14-rc7. It showed up in 5.13 and resolves an issue that Hans found.
  It has been in linux-next this week with no reported problems"

* tag 'usb-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb:
  usb: typec: tcpm: Fix VDMs sometimes not being forwarded to alt-mode drivers

Pull RISC-V fixes from Palmer Dabbelt:

 - fix the sifive-l2-cache device tree bindings for json-schema
   compatibility. This does not change the intended behavior of the
   binding.

 - avoid improperly freeing necessary resources during early boot.

* tag 'riscv-for-linus-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: Fix a number of free'd resources in init_resources()
  dt-bindings: sifive-l2-cache: Fix 'select' matching

Pull s390 fix from Vasily Gorbik:

 - fix use after free of zpci_dev in pci code

* tag 's390-5.14-5' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/pci: fix use after free of zpci_dev

Pull mandatory file locking deprecation warning from Jeff Layton:
 "As discussed on the list, this patch just adds a new warning for folks
  who still have mandatory locking enabled and actually mount with '-o
  mand'. I'd like to get this in for v5.14 so we can push this out into
  stable kernels and hopefully reach folks who have mounts with -o mand.

  For now, I'm operating under the assumption that we'll fully remove
  this support in v5.15, but we can move that out if any legitimate
  users of this facility speak up between now and then"

* tag 'locks-v5.14' of git://git.kernel.org/pub/scm/linux/kernel/git/jlayton/linux:
  fs: warn about impending deprecation of mandatory locks

Pull block fixes from Jens Axboe:
 "Three fixes from Ming Lei that should go into 5.14:

   - Fix for a kernel panic when iterating over tags for some cases
     where a flush request is present, a regression in this cycle.

   - Request timeout fix

   - Fix flush request checking"

* tag 'block-5.14-2021-08-20' of git://git.kernel.dk/linux-block:
  blk-mq: fix is_flush_rq
  blk-mq: fix kernel panic during iterating over flush request
  blk-mq: don't grab rq's refcount in blk_mq_check_expired()

Pull io_uring fixes from Jens Axboe:
 "A few small fixes that should go into this release:

   - Fix never re-assigning an initial error value for io_uring_enter()
     for SQPOLL, if asked to do nothing

   - Fix xa_alloc_cycle() return value checking, for cases where we have
     wrapped around

   - Fix for a ctx pin issue introduced in this cycle (Pavel)"

* tag 'io_uring-5.14-2021-08-20' of git://git.kernel.dk/linux-block:
  io_uring: fix xa_alloc_cycle() error return value check
  io_uring: pin ctx on fallback execution
  io_uring: only assign io_uring_enter() SQPOLL error in actual error case

We've had CONFIG_MANDATORY_FILE_LOCKING since 2015 and a lot of distros
have disabled it. Warn the stragglers that still use "-o mand" that
we'll be dropping support for that mount option.

Cc: stable@vger.kernel.org
Signed-off-by: Jeff Layton <jlayton@kernel.org>

We currently check for ret != 0 to indicate error, but '1' is a valid
return and just indicates that the allocation succeeded with a wrap.
Correct the check to be for < 0, like it was before the xarray
conversion.

Cc: stable@vger.kernel.org
Fixes: 61cf9370 ("io_uring: Convert personality_idr to XArray")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Pull ACPI fixes from Rafael Wysocki:
 "These fix two mistakes in new code.

  Specifics:

   - Prevent confusing messages from being printed if the PRMT table is
     not present or there are no PRM modules (Aubrey Li).

   - Fix the handling of suspend-to-idle entry and exit in the case when
     the Microsoft UUID is used with the Low-Power S0 Idle _DSM
     interface (Mario Limonciello)"

* tag 'acpi-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: PM: s2idle: Invert Microsoft UUID entry and exit
  ACPI: PRM: Deal with table not present or no module found

Pull power management fixes from Rafael Wysocki:
 "These fix some issues in the ARM cpufreq drivers and in the operating
  performance points (OPP) framework.

  Specifics:

   - Fix useless WARN() in the OPP core and prevent a noisy warning
     from being printed by OPP _put functions (Dmitry Osipenko).

   - Fix error path when allocation failed in the arm_scmi cpufreq
     driver (Lukasz Luba).

   - Blacklist Qualcomm sc8180x and Qualcomm sm8150 in
     cpufreq-dt-platdev (Bjorn Andersson, Thara Gopinath).

   - Forbid cpufreq for 1.2 GHz variant in the armada-37xx cpufreq
     driver (Marek Behún)"

* tag 'pm-5.14-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  opp: Drop empty-table checks from _put functions
  cpufreq: armada-37xx: forbid cpufreq for 1.2 GHz variant
  cpufreq: blocklist Qualcomm sm8150 in cpufreq-dt-platdev
  cpufreq: arm_scmi: Fix error path when allocation failed
  opp: remove WARN when no valid OPPs remain
  cpufreq: blacklist Qualcomm sc8180x in cpufreq-dt-platdev

Merge misc fixes from Andrew Morton:
 "10 patches.

  Subsystems affected by this patch series: MAINTAINERS and mm (shmem,
  pagealloc, tracing, memcg, memory-failure, vmscan, kfence, and
  hugetlb)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  hugetlb: don't pass page cache pages to restore_reserve_on_error
  kfence: fix is_kfence_address() for addresses below KFENCE_POOL_SIZE
  mm: vmscan: fix missing psi annotation for node_reclaim()
  mm/hwpoison: retry with shake_page() for unhandlable pages
  mm: memcontrol: fix occasional OOMs due to proportional memory.low reclaim
  MAINTAINERS: update ClangBuiltLinux IRC chat
  mmflags.h: add missing __GFP_ZEROTAGS and __GFP_SKIP_KASAN_POISON names
  mm/page_alloc: don't corrupt pcppage_migratetype
  Revert "mm: swap: check if swap backing device is congested or not"
  Revert "mm/shmem: fix shmem_swapin() race with swapoff"

Pull drm fixes from Dave Airlie:
 "Regularly scheduled fixes. The ttm one solves a problem of GPU drivers
  failing to load if debugfs is off in Kconfig, otherwise the i915 and
  mediatek, and amdgpu fixes all fairly normal.

  Nouveau has a couple of display fixes, but it has a fix for a
  longstanding race condition in it's memory manager code, and the fix
  mostly removes some code that wasn't working properly and has no
  userspace users. This fix makes the diffstat kinda larger but in a
  good (negative line-count) way.

  core:
   - fix drm_wait_vblank uapi copying bug

  ttm:
   - fix debugfs init when debugfs is off

  amdgpu:
   - vega10 SMU workload fix
   - DCN VM fix
   - DCN 3.01 watermark fix

  amdkfd:
   - SVM fix

  nouveau:
   - ampere display fixes
   - remove MM misfeature to fix a longstanding race condition

  i915:
   - tweaked display workaround for all PCHs
   - eDP MSO pipe sanity for ADL-P fix
   - remove unused symbol export

  mediatek:
   - AAL output size setting
   - Delete component in remove function"

* tag 'drm-fixes-2021-08-20-3' of git://anongit.freedesktop.org/drm/drm:
  drm/amd/display: Use DCN30 watermark calc for DCN301
  drm/i915/dp: remove superfluous EXPORT_SYMBOL()
  drm/i915/edp: fix eDP MSO pipe sanity checks for ADL-P
  drm/i915: Tweaked Wa_14010685332 for all PCHs
  drm/nouveau: rip out nvkm_client.super
  drm/nouveau: block a bunch of classes from userspace
  drm/nouveau/fifo/nv50-: rip out dma channels
  drm/nouveau/kms/nv50: workaround EFI GOP window channel format differences
  drm/nouveau/disp: power down unused DP links during init
  drm/nouveau: recognise GA107
  drm: Copy drm_wait_vblank to user before returning
  drm/amd/display: Ensure DCN save after VM setup
  drm/amdkfd: fix random KFDSVMRangeTest.SetGetAttributesTest test failure
  drm/amd/pm: change the workload type for some cards
  Revert "drm/amd/pm: fix workload mismatch on vega10"
  drm: ttm: Don't bail from ttm_global_init if debugfs_create_dir fails
  drm/mediatek: Add component_del in OVL and COLOR remove function
  drm/mediatek: Add AAL output size configuration

Pull PCI fixes from Bjorn Helgaas:

 - Add Rahul Tanwar as Intel LGM Gateway PCIe maintainer (Rahul Tanwar)

 - Add Jim Quinlan et al as Broadcom STB PCIe maintainers (Jim Quinlan)

 - Increase D3hot-to-D0 delay for AMD Renoir/Cezanne XHCI (Marcin
   Bachry)

 - Correct iomem_get_mapping() usage for legacy_mem sysfs (Krzysztof
   Wilczyński)

* tag 'pci-v5.14-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI/sysfs: Use correct variable for the legacy_mem sysfs object
  PCI: Increase D3 delay for AMD Renoir/Cezanne XHCI
  MAINTAINERS: Add Jim Quinlan et al as Broadcom STB PCIe maintainers
  MAINTAINERS: Add Rahul Tanwar as Intel LGM Gateway PCIe maintainer

Pull MMC host fixes from Ulf Hansson:

 - dw_mmc: Fix hang on data CRC error

 - mmci: Fix voltage switch procedure for the stm32 variant

 - sdhci-iproc: Fix some clock issues for BCM2711

 - sdhci-msm: Fixup software timeout value

* tag 'mmc-v5.14-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
  mmc: sdhci-iproc: Set SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN on BCM2711
  mmc: sdhci-iproc: Cap min clock frequency on BCM2711
  mmc: sdhci-msm: Update the software timeout value for sdhc
  mmc: mmci: stm32: Check when the voltage switch procedure should be done
  mmc: dw_mmc: Fix hang on data CRC error

Pull more sound fixes from Takashi Iwai:
 "This is a quick follow up for 5.14: a fix for a very recently
  introduced regression on ASoC Intel Atom driver, and another trivial
  HD-audio quirk for HP laptops"

* tag 'sound-5.14-rc7-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ASoC: intel: atom: Fix breakage for PCM buffer address setup
  ALSA: hda/realtek: Limit mic boost on HP ProBook 445 G8

Pull arm64 fixes from Will Deacon:

 - Fix cleaning of vDSO directories

 - Ensure CNTHCTL_EL2 is fully initialised when booting at EL2

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: initialize all of CNTHCTL_EL2
  arm64: clean vdso & vdso32 files

* acpi-pm:
  ACPI: PM: s2idle: Invert Microsoft UUID entry and exit

Pull iommu fixes from Joerg Roedel:

 - Fix for a potential NULL-ptr dereference in IOMMU core code

 - Two resource leak fixes

 - Cache flush fix in the Intel VT-d driver

* tag 'iommu-fixes-v5.14-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu:
  iommu/vt-d: Fix incomplete cache flush in intel_pasid_tear_down_entry()
  iommu/vt-d: Fix PASID reference leak
  iommu: Check if group is NULL before remove device
  iommu/dma: Fix leak in non-contiguous API

* pm-opp:
  opp: Drop empty-table checks from _put functions
  opp: remove WARN when no valid OPPs remain

syzbot hit kernel BUG at fs/hugetlbfs/inode.c:532 as described in [1].
This BUG triggers if the HPageRestoreReserve flag is set on a page in
the page cache.  It should never be set, as the routine
huge_add_to_page_cache explicitly clears the flag after adding a page to
the cache.

The only code other than huge page allocation which sets the flag is
restore_reserve_on_error.  It will potentially set the flag in rare out
of memory conditions.  syzbot was injecting errors to cause memory
allocation errors which exercised this specific path.

The code in restore_reserve_on_error is doing the right thing.  However,
there are instances where pages in the page cache were being passed to
restore_reserve_on_error.  This is incorrect, as once a page goes into
the cache reservation information will not be modified for the page
until it is removed from the cache.  Error paths do not remove pages
from the cache, so even in the case of error, the page will remain in
the cache and no reservation adjustment is needed.

Modify routines that potentially call restore_reserve_on_error with a
page cache page to no longer do so.

Note on fixes tag: Prior to commit 846be085 ("mm/hugetlb: expand
restore_reserve_on_error functionality") the routine would not process
page cache pages because the HPageRestoreReserve flag is not set on such
pages.  Therefore, this issue could not be trigggered.  The code added
by commit 846be085 ("mm/hugetlb: expand restore_reserve_on_error
functionality") is needed and correct.  It exposed incorrect calls to
restore_reserve_on_error which is the root cause addressed by this
commit.

[1] https://lore.kernel.org/linux-mm/00000000000050776d05c9b7c7f0@google.com/

Link: https://lkml.kernel.org/r/20210818213304.37038-1-mike.kravetz@oracle.com
Fixes: 846be085 ("mm/hugetlb: expand restore_reserve_on_error functionality")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Reported-by: <syzbot+67654e51e54455f1c585@syzkaller.appspotmail.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <naoya.horiguchi@linux.dev>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Originally the addr != NULL check was meant to take care of the case
where __kfence_pool == NULL (KFENCE is disabled).  However, this does
not work for addresses where addr > 0 && addr < KFENCE_POOL_SIZE.

This can be the case on NULL-deref where addr > 0 && addr < PAGE_SIZE or
any other faulting access with addr < KFENCE_POOL_SIZE.  While the
kernel would likely crash, the stack traces and report might be
confusing due to double faults upon KFENCE's attempt to unprotect such
an address.

Fix it by just checking that __kfence_pool != NULL instead.

Link: https://lkml.kernel.org/r/20210818130300.2482437-1-elver@google.com
Fixes: 0ce20dd8 ("mm: add Kernel Electric-Fence infrastructure")
Signed-off-by: Marco Elver <elver@google.com>
Reported-by: Kuan-Ying Lee <Kuan-Ying.Lee@mediatek.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <stable@vger.kernel.org>    [5.12+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In a debugging session the other day, Rik noticed that node_reclaim()
was missing memstall annotations.  This means we'll miss pressure and
lost productivity resulting from reclaim on an overloaded local NUMA
node when vm.zone_reclaim_mode is enabled.

There haven't been any reports, but that's likely because
vm.zone_reclaim_mode hasn't been a commonly used feature recently, and
the intersection between such setups and psi users is probably nil.

But secondary memory such as CXL-connected DIMMS, persistent memory etc,
and the page demotion patches that handle them
(https://lore.kernel.org/lkml/20210401183216.443C4443@viggo.jf.intel.com/)
could soon make this a more common codepath again.

Link: https://lkml.kernel.org/r/20210818152457.35846-1-hannes@cmpxchg.orgSigned-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reported-by: Rik van Riel <riel@surriel.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>