Pull cifs fixes from Steve French:
 "cifs/smb3 client fixes, mostly related to reconnect and/or DFS:

   - two important reconnect fixes: cases where status of recently
     connected IPCs and shares were not being updated leaving them in an
     incorrect state

   - fix for older Windows servers that would return
     STATUS_OBJECT_NAME_INVALID to query info requests on DFS links in a
     namespace that contained non-ASCII characters, reducing number of
     wasted roundtrips.

   - fix for leaked -ENOMEM to userspace when cifs.ko couldn't perform
     I/O due to a disconnected server, expired or deleted session.

   - removal of all unneeded DFS related mount option string parsing
     (now using fs_context for automounts)

   - improve clarity/readability, moving various DFS related functions
     out of fs/cifs/connect.c (which was getting too big to be readable)
     to new file.

   - Fix problem when large number of DFS connections. Allow sharing of
     DFS connections and fix how the referral paths are matched

   - Referral caching fix: Instead of looking up ipc connections to
     refresh cached referrals, store direct dfs root server's IPC
     pointer in new sessions so it can simply be accessed to either
     refresh or create a new referral that such connections belong to.

   - Fix to allow dfs root server's connections to also failover

   - Optimized reconnect of nested DFS links

   - Set correct status of IPC connections marked for reconnect"

* tag '6.2-rc-smb3-client-fixes-part2' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: update internal module number
  cifs: don't leak -ENOMEM in smb2_open_file()
  cifs: use origin fullpath for automounts
  cifs: set correct status of tcon ipc when reconnecting
  cifs: optimize reconnect of nested links
  cifs: fix source pathname comparison of dfs supers
  cifs: fix confusing debug message
  cifs: don't block in dfs_cache_noreq_update_tgthint()
  cifs: refresh root referrals
  cifs: fix refresh of cached referrals
  cifs: don't refresh cached referrals from unactive mounts
  cifs: share dfs connections and supers
  cifs: split out ses and tcon retrieval from mount_get_conns()
  cifs: set resolved ip in sockaddr
  cifs: remove unused smb3_fs_context::mount_options
  cifs: get rid of mount options string parsing
  cifs: use fs_context for automounts
  cifs: reduce roundtrips on create/qinfo requests
  cifs: set correct ipc status after initial tree connect
  cifs: set correct tcon status after initial tree connect

Pull ntfs3 updates from Konstantin Komarov:

 - added mount options 'hidedotfiles', 'nocase' and 'windows_names'

 - fixed xfstests (tested on x86_64): generic/083 generic/263
   generic/307 generic/465

 - fix some logic errors

 - code refactoring and dead code removal

* tag 'ntfs3_for_6.2' of https://github.com/Paragon-Software-Group/linux-ntfs3: (61 commits)
  fs/ntfs3: Make if more readable
  fs/ntfs3: Improve checking of bad clusters
  fs/ntfs3: Fix wrong if in hdr_first_de
  fs/ntfs3: Use ALIGN kernel macro
  fs/ntfs3: Fix incorrect if in ntfs_set_acl_ex
  fs/ntfs3: Check fields while reading
  fs/ntfs3: Correct ntfs_check_for_free_space
  fs/ntfs3: Restore correct state after ENOSPC in attr_data_get_block
  fs/ntfs3: Changing locking in ntfs_rename
  fs/ntfs3: Fixing wrong logic in attr_set_size and ntfs_fallocate
  fs/ntfs3: atomic_open implementation
  fs/ntfs3: Fix wrong indentations
  fs/ntfs3: Change new sparse cluster processing
  fs/ntfs3: Fixing work with sparse clusters
  fs/ntfs3: Simplify ntfs_update_mftmirr function
  fs/ntfs3: Remove unused functions
  fs/ntfs3: Fix sparse problems
  fs/ntfs3: Add ntfs_bitmap_weight_le function and refactoring
  fs/ntfs3: Use _le variants of bitops functions
  fs/ntfs3: Add functions to modify LE bitmaps
  ...

Merge tag 'fs.mount.propagation.fix.v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping

Pull mount propagation fix from Christian Brauner:
 "The propagate_mnt() function handles mount propagation when creating
  mounts and propagates the source mount tree @source_mnt to all
  applicable nodes of the destination propagation mount tree headed by
  @dest_mnt.

  Unfortunately it contains a bug where it fails to terminate at peers
  of @source_mnt when looking up copies of the source mount that become
  masters for copies of the source mount tree mounted on top of slaves
  in the destination propagation tree causing a NULL dereference.

  This fixes that bug (with a long commit message for a seven character
  fix but hopefully it'll help us fix issues faster in the future rather
  than having to go through the pain of having to relearn everything
  once more)"

* tag 'fs.mount.propagation.fix.v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping:
  pnode: terminate at peers of source

Pull HID updates from Benjamin Tissoires:

 - Four potential NULL pointers dereferences (Bastien Nocera, Enrik
   Berkhan, Jiasheng Jiang and Roderick Colenbrander)

 - Allow Wacom devices in bootloader mode to be flashed (Jason Gerecke)

 - Some assorted devices quirks (José Expósito and Terry Junge)

* tag 'for-linus-2022122101' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid:
  HID: sony: Fix unused function warning
  HID: plantronics: Additional PIDs for double volume key presses quirk
  HID: multitouch: fix Asus ExpertBook P2 P2451FA trackpoint
  HID: Ignore HP Envy x360 eu0009nv stylus battery
  HID: wacom: Ensure bootloader PID is usable in hidraw mode
  HID: amd_sfh: Add missing check for dma_alloc_coherent
  HID: playstation: fix free of uninialized pointer for DS4 in Bluetooth.
  HID: mcp2221: don't connect hidraw
  HID: logitech-hidpp: Guard FF init code against non-USB devices

Pull media fixes from Mauro Carvalho Chehab:

 - A regression at V4L2 core breaking string controls

 - Build warning fixes on sun6i drivers when building with clang

* tag 'media/v6.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media:
  media: sun6i-isp: params: Unregister pending buffer on cleanup
  media: sun6i-isp: params: Fix incorrect indentation
  media: sun6i-isp: capture: Fix uninitialized variable use
  media: sun6i-isp: proc: Declare subdev ops as static
  media: sun6i-isp: proc: Error out on invalid port to fix warning
  media: sun6i-isp: proc: Fix return code handling in stream off path
  media: sun8i-a83t-mipi-csi2: Clarify return code handling in stream off path
  media: sun6i-mipi-csi2: Clarify return code handling in stream off path
  media: sun6i-csi: capture: Remove useless ret initialization
  media: sun6i-csi: bridge: Error out on invalid port to fix warning
  media: v4l2-ctrls-api.c: add back dropped ctrl->is_new = 1

Merge tag 'pwm/for-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm

Pull pwm updates from Thierry Reding:
 "Various changes across the board, mostly improvements and cleanups"

* tag 'pwm/for-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/thierry.reding/linux-pwm: (42 commits)
  pwm: pca9685: Convert to i2c's .probe_new()
  pwm: sun4i: Propagate errors in .get_state() to the caller
  pwm: Handle .get_state() failures
  pwm: sprd: Propagate errors in .get_state() to the caller
  pwm: rockchip: Propagate errors in .get_state() to the caller
  pwm: mtk-disp: Propagate errors in .get_state() to the caller
  pwm: imx27: Propagate errors in .get_state() to the caller
  pwm: cros-ec: Propagate errors in .get_state() to the caller
  pwm: crc: Propagate errors in .get_state() to the caller
  leds: qcom-lpg: Propagate errors in .get_state() to the caller
  drm/bridge: ti-sn65dsi86: Propagate errors in .get_state() to the caller
  pwm/tracing: Also record trace events for failed API calls
  pwm: Make .get_state() callback return an error code
  pwm: pxa: Enable for MMP platform
  pwm: pxa: Add reference manual link and limitations
  pwm: pxa: Use abrupt shutdown mode
  pwm: pxa: Remove clk enable/disable from pxa_pwm_config
  pwm: pxa: Set duty cycle to 0 when disabling PWM
  pwm: pxa: Remove pxa_pwm_enable/disable
  pwm: mediatek: Add support for MT7986
  ...

Pull remoteproc updates from Bjorn Andersson:
 "rproc-virtio device names are now auto generated, to avoid conflicts
  between remoteproc instances.

  The imx_rproc driver is extended with support for communicating with
  and attaching to a running M4 on i.MX8QXP, as well as support for
  attaching to the M4 after self-recovering from a crash. Support is
  added for i.MX8QM and mailbox channels are reconnected during the
  recovery process, in order to avoid data corruption.

  The Xilinx Zynqmp firmware interface is extended and support for the
  Xilinx R5 RPU is introduced.

  Various resources leaks, primarily in error paths, throughout the
  Qualcomm drivers are corrected.

  Lastly a fix to ensure that pm_relax is invoked even if the remoteproc
  instance is stopped between a crash is being reported and the recovery
  handler is scheduled"

* tag 'rproc-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux: (25 commits)
  remoteproc: core: Do pm_relax when in RPROC_OFFLINE state
  remoteproc: qcom: q6v5: Fix missing clk_disable_unprepare() in q6v5_wcss_qcs404_power_on()
  remoteproc: qcom_q6v5_pas: Fix missing of_node_put() in adsp_alloc_memory_region()
  remoteproc: qcom_q6v5_pas: detach power domains on remove
  remoteproc: qcom_q6v5_pas: disable wakeup on probe fail or remove
  remoteproc: qcom: q6v5: Fix potential null-ptr-deref in q6v5_wcss_init_mmio()
  remoteproc: sysmon: fix memory leak in qcom_add_sysmon_subdev()
  remoteproc: sysmon: Make QMI message rules const
  drivers: remoteproc: Add Xilinx r5 remoteproc driver
  firmware: xilinx: Add RPU configuration APIs
  firmware: xilinx: Add shutdown/wakeup APIs
  firmware: xilinx: Add ZynqMP firmware ioctl enums for RPU configuration.
  arm64: dts: xilinx: zynqmp: Add RPU subsystem device node
  dt-bindings: remoteproc: Add Xilinx RPU subsystem bindings
  remoteproc: core: Use device_match_of_node()
  remoteproc: imx_rproc: Correct i.MX93 DRAM mapping
  remoteproc: imx_rproc: Enable attach recovery for i.MX8QM/QXP
  remoteproc: imx_rproc: Request mbox channel later
  remoteproc: imx_rproc: Support i.MX8QM
  remoteproc: imx_rproc: Support kicking Mcore from Linux for i.MX8QXP
  ...

Pull mailbox updates from Jassi Brar:

 - qcom: enable sc8280xp, sm8550 and sm4250 support

 - ti: default to ARCH_K3 for msg manager

 - mediatek:
    - add mt8188 and mt8186 support
    - request irq only after got ready

 - zynq-ipi: fix error handling after device_register

 - mpfs: check sys-con status

 - rockchip: simplify by using device_get_match_data

* tag 'mailbox-v6.2' of git://git.linaro.org/landing-teams/working/fujitsu/integration:
  dt-bindings: mailbox: qcom-ipcc: Add compatible for SM8550
  mailbox: mtk-cmdq: Do not request irq until we are ready
  mailbox: zynq-ipi: fix error handling while device_register() fails
  mailbox: mtk-cmdq-mailbox: Use platform data directly instead of copying
  mailbox: arm_mhuv2: Fix return value check in mhuv2_probe()
  dt-bindings: mailbox: mediatek,gce-mailbox: add mt8188 compatible name
  dt-bindings: mailbox: add GCE header file for mt8188
  mailbox: mpfs: read the system controller's status
  mailbox: mtk-cmdq: add MT8186 support
  mailbox: mtk-cmdq: add gce ddr enable support flow
  mailbox: mtk-cmdq: add gce software ddr enable private data
  mailbox: mtk-cmdq: Use GCE_CTRL_BY_SW definition instead of number
  mailbox: rockchip: Use device_get_match_data() to simplify the code
  dt-bindings: mailbox: qcom-ipcc: Add sc8280xp compatible
  mailbox: config: ti-msgmgr: Default set to ARCH_K3 for TI msg manager
  mailbox: qcom-apcs-ipc: Add SM4250 APCS IPC support
  dt-bindings: mailbox: qcom: Add SM4250 APCS compatible

Pull backlight update from Lee Jones:
 "Convert a bunch of I2C class drivers over to .probe_new()"

* tag 'backlight-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/backlight:
  backlight: tosa: Convert to i2c's .probe_new()
  backlight: lv5207lp: Convert to i2c's .probe_new()
  backlight: lp855x: Convert to i2c's .probe_new()
  backlight: lm3639: Convert to i2c's .probe_new()
  backlight: lm3630a: Convert to i2c's .probe_new()
  backlight: bd6107: Convert to i2c's .probe_new()
  backlight: arcxcnn: Convert to i2c's .probe_new()
  backlight: adp8870: Convert to i2c's .probe_new()
  backlight: adp8860: Convert to i2c's .probe_new()

Pull MFD updates from Lee Jones:
 "New Drivers:
   - Add support for Ampere Computing SMpro
   - Add support for TI TPS65219 PMIC

  New Functionality:
   - Add support for multiple devices of the same type; rk808

  Fix-ups:
   - Convert a bunch of I2C class drivers over to .probe_new()
   - Remove superfluous includes; mc13xxx-*, palmas, timberdale
   - Use correct includes for GPIO handling; madera-core
   - Convert to GPIOD; twl6040
   - Remove unused platform data handling; twl6040
   - Device Tree changes; many
   - Remove unused drivers; dm355evm_msp, davinci_voicecodec, htc-i2cpld
   - Add support for modules; palmas
   - Enable COMPILE_TEST support; intel_soc_pmic*
   - Trivial: spelling / whitespace fixes; mc13xxx-spi
   - Replace old PM helpers with new ones; many
   - Convert deprecated mask_invert usage to unmask_base; many
   - Use devm_*() calls; qcom_rpm
   - MAINTAINER fix-ups
   - Make use of improved / replaced APIs; palmas, fsl-imx25-tsadc,
     stm32-lptimer, qcom_rpm, rohm-*

  Bug Fixes:
   - Add bounds / error checking; mt6360-core
   - No sleeping inside critical sections; axp20x
   - Fix missing dependencies; ROHM_BD957XMUF
   - Repair error paths; qcom-pm8008"

* tag 'mfd-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd: (161 commits)
  dt-bindings: mfd: da9062: Correct file name for watchdog
  mfd: pm8008: Fix return value check in pm8008_probe()
  mfd: rohm: Use dev_err_probe()
  mfd: Drop obsolete dependencies on COMPILE_TEST
  dt-bindings: mfd: da9062: Move IRQ to optional properties
  mfd: qcom_rpm: Use devm_of_platform_populate() to simplify code
  mfd: qcom_rpm: Fix an error handling path in qcom_rpm_probe()
  mfd: stm32-lptimer: Use devm_platform_get_and_ioremap_resource()
  mfd: rohm-bd9576: Convert to i2c's .probe_new()
  mfd: fsl-imx25-tsadc: Use devm_platform_get_and_ioremap_resource()
  dt-bindings: Fix maintainer email for a few ROHM ICs
  mfd: palmas: Use device_get_match_data() to simplify the code
  Input: Add tps65219 interrupt driven powerbutton
  mfd: tps65219: Add driver for TI TPS65219 PMIC
  mfd: bd957x: Fix Kconfig dependency on REGMAP_IRQ
  mfd: wcd934x: Convert irq chip to config regs
  mfd: tps65090: Replace irqchip mask_invert with unmask_base
  mfd: sun4i-gpadc: Replace irqchip mask_invert with unmask_base
  mfd: stpmic1: Fix swapped mask/unmask in irq chip
  mfd: sprd-sc27xx-spi: Replace irqchip mask_invert with unmask_base
  ...

The m68 hand-written assembler version of strcmp() has always been
broken: it returns the difference between the first non-matching byte
done as a 8-bit subtraction.

That is _almost_ right, but is broken for the overflow case.  The
strcmp() function should indeed return the sign of the difference
between the first byte that differs, but the subtraction needs to be
done in a wider type than 'char'.  Otherwise the ordering isn't actually
stable.

This went unnoticed for basically forever, because nobody ever cares
about non-US-ASCII orderings in the kernel (in fact, most users only
care about "exact match or not"), so overflows don't really happen in
practice, even if it was very very wrong.

But that mostly unnoticeable bug becomes very noticeable by the recent
change to make 'char' be unsigned in the kernel across all architectures
(commit 3bc753c0: "kbuild: treat char as always unsigned"). Because
the code not only did the subtraction in the wrong type width, it also
used 'char' to then make the compiler expand the result from an 8-bit
difference to the 'int' return value.

So now with an unsigned char that incorrect arithmetic width was then
not even sign-expanded, and always returned just a positive integer.

We could re-instate the old broken code by just turning the 'char' into
'signed char' as has been done elsewhere where people depended on the
signedness of 'char', but since the whole function was broken to begin
with, and we have a non-broken default fallback implementation, let's
just remove this broken function entirely.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/lkml/20221221145332.GA2399037@roeck-us.net/
Cc: Jason Donenfeld <Jason@zx2c4.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Rasmus Villemoes <rasmus.villemoes@prevas.dk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull networking fixes from Jakub Kicinski:
 "Including fixes from bpf, netfilter and can.

  Current release - regressions:

   - bpf: synchronize dispatcher update with bpf_dispatcher_xdp_func

   - rxrpc:
      - fix security setting propagation
      - fix null-deref in rxrpc_unuse_local()
      - fix switched parameters in peer tracing

  Current release - new code bugs:

   - rxrpc:
      - fix I/O thread startup getting skipped
      - fix locking issues in rxrpc_put_peer_locked()
      - fix I/O thread stop
      - fix uninitialised variable in rxperf server
      - fix the return value of rxrpc_new_incoming_call()

   - microchip: vcap: fix initialization of value and mask

   - nfp: fix unaligned io read of capabilities word

  Previous releases - regressions:

   - stop in-kernel socket users from corrupting socket's task_frag

   - stream: purge sk_error_queue in sk_stream_kill_queues()

   - openvswitch: fix flow lookup to use unmasked key

   - dsa: mv88e6xxx: avoid reg_lock deadlock in mv88e6xxx_setup_port()

   - devlink:
      - hold region lock when flushing snapshots
      - protect devlink dump by the instance lock

  Previous releases - always broken:

   - bpf:
      - prevent leak of lsm program after failed attach
      - resolve fext program type when checking map compatibility

   - skbuff: account for tail adjustment during pull operations

   - macsec: fix net device access prior to holding a lock

   - bonding: switch back when high prio link up

   - netfilter: flowtable: really fix NAT IPv6 offload

   - enetc: avoid buffer leaks on xdp_do_redirect() failure

   - unix: fix race in SOCK_SEQPACKET's unix_dgram_sendmsg()

   - dsa: microchip: remove IRQF_TRIGGER_FALLING in
     request_threaded_irq"

* tag 'net-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (64 commits)
  net: fec: check the return value of build_skb()
  net: simplify sk_page_frag
  Treewide: Stop corrupting socket's task_frag
  net: Introduce sk_use_task_frag in struct sock.
  mctp: Remove device type check at unregister
  net: dsa: microchip: remove IRQF_TRIGGER_FALLING in request_threaded_irq
  can: kvaser_usb: hydra: help gcc-13 to figure out cmd_len
  can: flexcan: avoid unbalanced pm_runtime_enable warning
  Documentation: devlink: add missing toc entry for etas_es58x devlink doc
  mctp: serial: Fix starting value for frame check sequence
  nfp: fix unaligned io read of capabilities word
  net: stream: purge sk_error_queue in sk_stream_kill_queues()
  myri10ge: Fix an error handling path in myri10ge_probe()
  net: microchip: vcap: Fix initialization of value and mask
  rxrpc: Fix the return value of rxrpc_new_incoming_call()
  rxrpc: rxperf: Fix uninitialised variable
  rxrpc: Fix I/O thread stop
  rxrpc: Fix switched parameters in peer tracing
  rxrpc: Fix locking issues in rxrpc_put_peer_locked()
  rxrpc: Fix I/O thread startup getting skipped
  ...

Pull vfsuid cleanup from Christian Brauner:
 "This moves the ima specific vfs{g,u}id_t comparison helpers out of the
  header and into the one file in ima where they are used.

  We shouldn't incentivize people to use them by placing them into the
  header. As discussed and suggested by Linus in [1] let's just define
  them locally in the one file in ima where they are used"

Link: https://lore.kernel.org/lkml/CAHk-=wj4BpEwUd=OkTv1F9uykvSrsBNZJVHMp+p_+e2kiV71_A@mail.gmail.com [1]

* tag 'fs.vfsuid.ima.v6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/idmapping:
  mnt_idmapping: move ima-only helpers to ima

Pull more random number generator updates from Jason Donenfeld:
 "Two remaining changes that are now possible after you merged a few
  other trees:

   - #include <asm/archrandom.h> can be removed from random.h now,
     making the direct use of the arch_random_* API more of a private
     implementation detail between the archs and random.c, rather than
     something for general consumers.

   - Two additional uses of prandom_u32_max() snuck in during the
     initial phase of pulls, so these have been converted to
     get_random_u32_below(), and now the deprecated prandom_u32_max()
     alias -- which was just a wrapper around get_random_u32_below() --
     can be removed.

  In addition, there is one fix:

   - Check efi_rt_services_supported() before attempting to use an EFI
     runtime function.

     This affected EFI systems that disable runtime services yet still
     boot via EFI (e.g. the reporter's Lenovo Thinkpad X13s laptop), as
     well systems where EFI runtime services have been forcibly
     disabled, such as on PREEMPT_RT.

     On those machines, a very early and hard to diagnose crash would
     happen, preventing boot"

* tag 'random-6.2-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
  prandom: remove prandom_u32_max()
  efi: random: fix NULL-deref when refreshing seed
  random: do not include <asm/archrandom.h> from random.h

Merge tag 'rcu-urgent.2022.12.17a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull RCU fix from Paul McKenney:
 "This fixes a lockdep false positive in synchronize_rcu() that can
  otherwise occur during early boot.

  The fix simply avoids invoking lockdep if the scheduler has not yet
  been initialized, that is, during that portion of boot when interrupts
  are disabled"

* tag 'rcu-urgent.2022.12.17a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu:
  rcu: Don't assert interrupts enabled too early in boot

The propagate_mnt() function handles mount propagation when creating
mounts and propagates the source mount tree @source_mnt to all
applicable nodes of the destination propagation mount tree headed by
@dest_mnt.

Unfortunately it contains a bug where it fails to terminate at peers of
@source_mnt when looking up copies of the source mount that become
masters for copies of the source mount tree mounted on top of slaves in
the destination propagation tree causing a NULL dereference.

Once the mechanics of the bug are understood it's easy to trigger.
Because of unprivileged user namespaces it is available to unprivileged
users.

While fixing this bug we've gotten confused multiple times due to
unclear terminology or missing concepts. So let's start this with some
clarifications:

* The terms "master" or "peer" denote a shared mount. A shared mount
  belongs to a peer group.

* A peer group is a set of shared mounts that propagate to each other.
  They are identified by a peer group id. The peer group id is available
  in @shared_mnt->mnt_group_id.
  Shared mounts within the same peer group have the same peer group id.
  The peers in a peer group can be reached via @shared_mnt->mnt_share.

* The terms "slave mount" or "dependent mount" denote a mount that
  receives propagation from a peer in a peer group. IOW, shared mounts
  may have slave mounts and slave mounts have shared mounts as their
  master. Slave mounts of a given peer in a peer group are listed on
  that peers slave list available at @shared_mnt->mnt_slave_list.

* The term "master mount" denotes a mount in a peer group. IOW, it
  denotes a shared mount or a peer mount in a peer group. The term
  "master mount" - or "master" for short - is mostly used when talking
  in the context of slave mounts that receive propagation from a master
  mount. A master mount of a slave identifies the closest peer group a
  slave mount receives propagation from. The master mount of a slave can
  be identified via @slave_mount->mnt_master. Different slaves may point
  to different masters in the same peer group.

* Multiple peers in a peer group can have non-empty ->mnt_slave_lists.
  Non-empty ->mnt_slave_lists of peers don't intersect. Consequently, to
  ensure all slave mounts of a peer group are visited the
  ->mnt_slave_lists of all peers in a peer group have to be walked.

* Slave mounts point to a peer in the closest peer group they receive
  propagation from via @slave_mnt->mnt_master (see above). Together with
  these peers they form a propagation group (see below). The closest
  peer group can thus be identified through the peer group id
  @slave_mnt->mnt_master->mnt_group_id of the peer/master that a slave
  mount receives propagation from.

* A shared-slave mount is a slave mount to a peer group pg1 while also
  a peer in another peer group pg2. IOW, a peer group may receive
  propagation from another peer group.

  If a peer group pg1 is a slave to another peer group pg2 then all
  peers in peer group pg1 point to the same peer in peer group pg2 via
  ->mnt_master. IOW, all peers in peer group pg1 appear on the same
  ->mnt_slave_list. IOW, they cannot be slaves to different peer groups.

* A pure slave mount is a slave mount that is a slave to a peer group
  but is not a peer in another peer group.

* A propagation group denotes the set of mounts consisting of a single
  peer group pg1 and all slave mounts and shared-slave mounts that point
  to a peer in that peer group via ->mnt_master. IOW, all slave mounts
  such that @slave_mnt->mnt_master->mnt_group_id is equal to
  @shared_mnt->mnt_group_id.

  The concept of a propagation group makes it easier to talk about a
  single propagation level in a propagation tree.

  For example, in propagate_mnt() the immediate peers of @dest_mnt and
  all slaves of @dest_mnt's peer group form a propagation group propg1.
  So a shared-slave mount that is a slave in propg1 and that is a peer
  in another peer group pg2 forms another propagation group propg2
  together with all slaves that point to that shared-slave mount in
  their ->mnt_master.

* A propagation tree refers to all mounts that receive propagation
  starting from a specific shared mount.

  For example, for propagate_mnt() @dest_mnt is the start of a
  propagation tree. The propagation tree ecompasses all mounts that
  receive propagation from @dest_mnt's peer group down to the leafs.

With that out of the way let's get to the actual algorithm.

We know that @dest_mnt is guaranteed to be a pure shared mount or a
shared-slave mount. This is guaranteed by a check in
attach_recursive_mnt(). So propagate_mnt() will first propagate the
source mount tree to all peers in @dest_mnt's peer group:

for (n = next_peer(dest_mnt); n != dest_mnt; n = next_peer(n)) {
        ret = propagate_one(n);
        if (ret)
               goto out;
}

Notice, that the peer propagation loop of propagate_mnt() doesn't
propagate @dest_mnt itself. @dest_mnt is mounted directly in
attach_recursive_mnt() after we propagated to the destination
propagation tree.

The mount that will be mounted on top of @dest_mnt is @source_mnt. This
copy was created earlier even before we entered attach_recursive_mnt()
and doesn't concern us a lot here.

It's just important to notice that when propagate_mnt() is called
@source_mnt will not yet have been mounted on top of @dest_mnt. Thus,
@source_mnt->mnt_parent will either still point to @source_mnt or - in
the case @source_mnt is moved and thus already attached - still to its
former parent.

For each peer @M in @dest_mnt's peer group propagate_one() will create a
new copy of the source mount tree and mount that copy @child on @M such
that @child->mnt_parent points to @M after propagate_one() returns.

propagate_one() will stash the last destination propagation node @M in
@last_dest and the last copy it created for the source mount tree in
@last_source.

Hence, if we call into propagate_one() again for the next destination
propagation node @M, @last_dest will point to the previous destination
propagation node and @last_source will point to the previous copy of the
source mount tree and mounted on @last_dest.

Each new copy of the source mount tree is created from the previous copy
of the source mount tree. This will become important later.

The peer loop in propagate_mnt() is straightforward. We iterate through
the peers copying and updating @last_source and @last_dest as we go
through them and mount each copy of the source mount tree @child on a
peer @M in @dest_mnt's peer group.

After propagate_mnt() handled the peers in @dest_mnt's peer group
propagate_mnt() will propagate the source mount tree down the
propagation tree that @dest_mnt's peer group propagates to:

for (m = next_group(dest_mnt, dest_mnt); m;
                m = next_group(m, dest_mnt)) {
        /* everything in that slave group */
        n = m;
        do {
                ret = propagate_one(n);
                if (ret)
                        goto out;
                n = next_peer(n);
        } while (n != m);
}

The next_group() helper will recursively walk the destination
propagation tree, descending into each propagation group of the
propagation tree.

The important part is that it takes care to propagate the source mount
tree to all peers in the peer group of a propagation group before it
propagates to the slaves to those peers in the propagation group. IOW,
it creates and mounts copies of the source mount tree that become
masters before it creates and mounts copies of the source mount tree
that become slaves to these masters.

It is important to remember that propagating the source mount tree to
each mount @M in the destination propagation tree simply means that we
create and mount new copies @child of the source mount tree on @M such
that @child->mnt_parent points to @M.

Since we know that each node @M in the destination propagation tree
headed by @dest_mnt's peer group will be overmounted with a copy of the
source mount tree and since we know that the propagation properties of
each copy of the source mount tree we create and mount at @M will mostly
mirror the propagation properties of @M. We can use that information to
create and mount the copies of the source mount tree that become masters
before their slaves.

The easy case is always when @M and @last_dest are peers in a peer group
of a given propagation group. In that case we know that we can simply
copy @last_source without having to figure out what the master for the
new copy @child of the source mount tree needs to be as we've done that
in a previous call to propagate_one().

The hard case is when we're dealing with a slave mount or a shared-slave
mount @M in a destination propagation group that we need to create and
mount a copy of the source mount tree on.

For each propagation group in the destination propagation tree we
propagate the source mount tree to we want to make sure that the copies
@child of the source mount tree we create and mount on slaves @M pick an
ealier copy of the source mount tree that we mounted on a master @M of
the destination propagation group as their master. This is a mouthful
but as far as we can tell that's the core of it all.

But, if we keep track of the masters in the destination propagation tree
@M we can use the information to find the correct master for each copy
of the source mount tree we create and mount at the slaves in the
destination propagation tree @M.

Let's walk through the base case as that's still fairly easy to grasp.

If we're dealing with the first slave in the propagation group that
@dest_mnt is in then we don't yet have marked any masters in the
destination propagation tree.

We know the master for the first slave to @dest_mnt's peer group is
simple @dest_mnt. So we expect this algorithm to yield a copy of the
source mount tree that was mounted on a peer in @dest_mnt's peer group
as the master for the copy of the source mount tree we want to mount at
the first slave @M:

for (n = m; ; n = p) {
        p = n->mnt_master;
        if (p == dest_master || IS_MNT_MARKED(p))
                break;
}

For the first slave we walk the destination propagation tree all the way
up to a peer in @dest_mnt's peer group. IOW, the propagation hierarchy
can be walked by walking up the @mnt->mnt_master hierarchy of the
destination propagation tree @M. We will ultimately find a peer in
@dest_mnt's peer group and thus ultimately @dest_mnt->mnt_master.

Btw, here the assumption we listed at the beginning becomes important.
Namely, that peers in a peer group pg1 that are slaves in another peer
group pg2 appear on the same ->mnt_slave_list. IOW, all slaves who are
peers in peer group pg1 point to the same peer in peer group pg2 via
their ->mnt_master. Otherwise the termination condition in the code
above would be wrong and next_group() would be broken too.

So the first iteration sets:

n = m;
p = n->mnt_master;

such that @p now points to a peer or @dest_mnt itself. We walk up one
more level since we don't have any marked mounts. So we end up with:

n = dest_mnt;
p = dest_mnt->mnt_master;

If @dest_mnt's peer group is not slave to another peer group then @p is
now NULL. If @dest_mnt's peer group is a slave to another peer group
then @p now points to @dest_mnt->mnt_master points which is a master
outside the propagation tree we're dealing with.

Now we need to figure out the master for the copy of the source mount
tree we're about to create and mount on the first slave of @dest_mnt's
peer group:

do {
        struct mount *parent = last_source->mnt_parent;
        if (last_source == first_source)
                break;
        done = parent->mnt_master == p;
        if (done && peers(n, parent))
                break;
        last_source = last_source->mnt_master;
} while (!done);

We know that @last_source->mnt_parent points to @last_dest and
@last_dest is the last peer in @dest_mnt's peer group we propagated to
in the peer loop in propagate_mnt().

Consequently, @last_source is the last copy we created and mount on that
last peer in @dest_mnt's peer group. So @last_source is the master we
want to pick.

We know that @last_source->mnt_parent->mnt_master points to
@last_dest->mnt_master. We also know that @last_dest->mnt_master is
either NULL or points to a master outside of the destination propagation
tree and so does @p. Hence:

done = parent->mnt_master == p;

is trivially true in the base condition.

We also know that for the first slave mount of @dest_mnt's peer group
that @last_dest either points @dest_mnt itself because it was
initialized to:

last_dest = dest_mnt;

at the beginning of propagate_mnt() or it will point to a peer of
@dest_mnt in its peer group. In both cases it is guaranteed that on the
first iteration @n and @parent are peers (Please note the check for
peers here as that's important.):

if (done && peers(n, parent))
        break;

So, as we expected, we select @last_source, which referes to the last
copy of the source mount tree we mounted on the last peer in @dest_mnt's
peer group, as the master of the first slave in @dest_mnt's peer group.
The rest is taken care of by clone_mnt(last_source, ...). We'll skip
over that part otherwise this becomes a blogpost.

At the end of propagate_mnt() we now mark @m->mnt_master as the first
master in the destination propagation tree that is distinct from
@dest_mnt->mnt_master. IOW, we mark @dest_mnt itself as a master.

By marking @dest_mnt or one of it's peers we are able to easily find it
again when we later lookup masters for other copies of the source mount
tree we mount copies of the source mount tree on slaves @M to
@dest_mnt's peer group. This, in turn allows us to find the master we
selected for the copies of the source mount tree we mounted on master in
the destination propagation tree again.

The important part is to realize that the code makes use of the fact
that the last copy of the source mount tree stashed in @last_source was
mounted on top of the previous destination propagation node @last_dest.
What this means is that @last_source allows us to walk the destination
propagation hierarchy the same way each destination propagation node @M
does.

If we take @last_source, which is the copy of @source_mnt we have
mounted on @last_dest in the previous iteration of propagate_one(), then
we know @last_source->mnt_parent points to @last_dest but we also know
that as we walk through the destination propagation tree that
@last_source->mnt_master will point to an earlier copy of the source
mount tree we mounted one an earlier destination propagation node @M.

IOW, @last_source->mnt_parent will be our hook into the destination
propagation tree and each consecutive @last_source->mnt_master will lead
us to an earlier propagation node @M via
@last_source->mnt_master->mnt_parent.

Hence, by walking up @last_source->mnt_master, each of which is mounted
on a node that is a master @M in the destination propagation tree we can
also walk up the destination propagation hierarchy.

So, for each new destination propagation node @M we use the previous
copy of @last_source and the fact it's mounted on the previous
propagation node @last_dest via @last_source->mnt_master->mnt_parent to
determine what the master of the new copy of @last_source needs to be.

The goal is to find the _closest_ master that the new copy of the source
mount tree we are about to create and mount on a slave @M in the
destination propagation tree needs to pick. IOW, we want to find a
suitable master in the propagation group.

As the propagation structure of the source mount propagation tree we
create mirrors the propagation structure of the destination propagation
tree we can find @M's closest master - i.e., a marked master - which is
a peer in the closest peer group that @M receives propagation from. We
store that closest master of @M in @p as before and record the slave to
that master in @n

We then search for this master @p via @last_source by walking up the
master hierarchy starting from the last copy of the source mount tree
stored in @last_source that we created and mounted on the previous
destination propagation node @M.

We will try to find the master by walking @last_source->mnt_master and
by comparing @last_source->mnt_master->mnt_parent->mnt_master to @p. If
we find @p then we can figure out what earlier copy of the source mount
tree needs to be the master for the new copy of the source mount tree
we're about to create and mount at the current destination propagation
node @M.

If @last_source->mnt_master->mnt_parent and @n are peers then we know
that the closest master they receive propagation from is
@last_source->mnt_master->mnt_parent->mnt_master. If not then the
closest immediate peer group that they receive propagation from must be
one level higher up.

This builds on the earlier clarification at the beginning that all peers
in a peer group which are slaves of other peer groups all point to the
same ->mnt_master, i.e., appear on the same ->mnt_slave_list, of the
closest peer group that they receive propagation from.

However, terminating the walk has corner cases.

If the closest marked master for a given destination node @M cannot be
found by walking up the master hierarchy via @last_source->mnt_master
then we need to terminate the walk when we encounter @source_mnt again.

This isn't an arbitrary termination. It simply means that the new copy
of the source mount tree we're about to create has a copy of the source
mount tree we created and mounted on a peer in @dest_mnt's peer group as
its master. IOW, @source_mnt is the peer in the closest peer group that
the new copy of the source mount tree receives propagation from.

We absolutely have to stop @source_mnt because @last_source->mnt_master
either points outside the propagation hierarchy we're dealing with or it
is NULL because @source_mnt isn't a shared-slave.

So continuing the walk past @source_mnt would cause a NULL dereference
via @last_source->mnt_master->mnt_parent. And so we have to stop the
walk when we encounter @source_mnt again.

One scenario where this can happen is when we first handled a series of
slaves of @dest_mnt's peer group and then encounter peers in a new peer
group that is a slave to @dest_mnt's peer group. We handle them and then
we encounter another slave mount to @dest_mnt that is a pure slave to
@dest_mnt's peer group. That pure slave will have a peer in @dest_mnt's
peer group as its master. Consequently, the new copy of the source mount
tree will need to have @source_mnt as it's master. So we walk the
propagation hierarchy all the way up to @source_mnt based on
@last_source->mnt_master.

So terminate on @source_mnt, easy peasy. Except, that the check misses
something that the rest of the algorithm already handles.

If @dest_mnt has peers in it's peer group the peer loop in
propagate_mnt():

for (n = next_peer(dest_mnt); n != dest_mnt; n = next_peer(n)) {
        ret = propagate_one(n);
        if (ret)
                goto out;
}

will consecutively update @last_source with each previous copy of the
source mount tree we created and mounted at the previous peer in
@dest_mnt's peer group. So after that loop terminates @last_source will
point to whatever copy of the source mount tree was created and mounted
on the last peer in @dest_mnt's peer group.

Furthermore, if there is even a single additional peer in @dest_mnt's
peer group then @last_source will __not__ point to @source_mnt anymore.
Because, as we mentioned above, @dest_mnt isn't even handled in this
loop but directly in attach_recursive_mnt(). So it can't even accidently
come last in that peer loop.

So the first time we handle a slave mount @M of @dest_mnt's peer group
the copy of the source mount tree we create will make the __last copy of
the source mount tree we created and mounted on the last peer in
@dest_mnt's peer group the master of the new copy of the source mount
tree we create and mount on the first slave of @dest_mnt's peer group__.

But this means that the termination condition that checks for
@source_mnt is wrong. The @source_mnt cannot be found anymore by
propagate_one(). Instead it will find the last copy of the source mount
tree we created and mounted for the last peer of @dest_mnt's peer group
again. And that is a peer of @source_mnt not @source_mnt itself.

IOW, we fail to terminate the loop correctly and ultimately dereference
@last_source->mnt_master->mnt_parent. When @source_mnt's peer group
isn't slave to another peer group then @last_source->mnt_master is NULL
causing the splat below.

For example, assume @dest_mnt is a pure shared mount and has three peers
in its peer group:

===================================================================================
                                         mount-id   mount-parent-id   peer-group-id
===================================================================================
(@dest_mnt) mnt_master[216]              309        297               shared:216
    \
     (@source_mnt) mnt_master[218]:      609        609               shared:218

(1) mnt_master[216]:                     607        605               shared:216
    \
     (P1) mnt_master[218]:               624        607               shared:218

(2) mnt_master[216]:                     576        574               shared:216
    \
     (P2) mnt_master[218]:               625        576               shared:218

(3) mnt_master[216]:                     545        543               shared:216
    \
     (P3) mnt_master[218]:               626        545               shared:218

After this sequence has been processed @last_source will point to (P3),
the copy generated for the third peer in @dest_mnt's peer group we
handled. So the copy of the source mount tree (P4) we create and mount
on the first slave of @dest_mnt's peer group:

===================================================================================
                                         mount-id   mount-parent-id   peer-group-id
===================================================================================
    mnt_master[216]                      309        297               shared:216
   /
  /
(S0) mnt_slave                           483        481               master:216
  \
   \    (P3) mnt_master[218]             626        545               shared:218
    \  /
     \/
    (P4) mnt_slave                       627        483               master:218

will pick the last copy of the source mount tree (P3) as master, not (S0).

When walking the propagation hierarchy via @last_source's master
hierarchy we encounter (P3) but not (S0), i.e., @source_mnt.

We can fix this in multiple ways:

(1) By setting @last_source to @source_mnt after we processed the peers
    in @dest_mnt's peer group right after the peer loop in
    propagate_mnt().

(2) By changing the termination condition that relies on finding exactly
    @source_mnt to finding a peer of @source_mnt.

(3) By only moving @last_source when we actually venture into a new peer
    group or some clever variant thereof.

The first two options are minimally invasive and what we want as a fix.
The third option is more intrusive but something we'd like to explore in
the near future.

This passes all LTP tests and specifically the mount propagation
testsuite part of it. It also holds up against all known reproducers of
this issues.

Final words.
First, this is a clever but __worringly__ underdocumented algorithm.
There isn't a single detailed comment to be found in next_group(),
propagate_one() or anywhere else in that file for that matter. This has
been a giant pain to understand and work through and a bug like this is
insanely difficult to fix without a detailed understanding of what's
happening. Let's not talk about the amount of time that was sunk into
fixing this.

Second, all the cool kids with access to
unshare --mount --user --map-root --propagation=unchanged
are going to have a lot of fun. IOW, triggerable by unprivileged users
while namespace_lock() lock is held.

[  115.848393] BUG: kernel NULL pointer dereference, address: 0000000000000010
[  115.848967] #PF: supervisor read access in kernel mode
[  115.849386] #PF: error_code(0x0000) - not-present page
[  115.849803] PGD 0 P4D 0
[  115.850012] Oops: 0000 [#1] PREEMPT SMP PTI
[  115.850354] CPU: 0 PID: 15591 Comm: mount Not tainted 6.1.0-rc7 #3
[  115.850851] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS
VirtualBox 12/01/2006
[  115.851510] RIP: 0010:propagate_one.part.0+0x7f/0x1a0
[  115.851924] Code: 75 eb 4c 8b 05 c2 25 37 02 4c 89 ca 48 8b 4a 10
49 39 d0 74 1e 48 3b 81 e0 00 00 00 74 26 48 8b 92 e0 00 00 00 be 01
00 00 00 <48> 8b 4a 10 49 39 d0 75 e2 40 84 f6 74 38 4c 89 05 84 25 37
02 4d
[  115.853441] RSP: 0018:ffffb8d5443d7d50 EFLAGS: 00010282
[  115.853865] RAX: ffff8e4d87c41c80 RBX: ffff8e4d88ded780 RCX: ffff8e4da4333a00
[  115.854458] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8e4d88ded780
[  115.855044] RBP: ffff8e4d88ded780 R08: ffff8e4da4338000 R09: ffff8e4da43388c0
[  115.855693] R10: 0000000000000002 R11: ffffb8d540158000 R12: ffffb8d5443d7da8
[  115.856304] R13: ffff8e4d88ded780 R14: 0000000000000000 R15: 0000000000000000
[  115.856859] FS:  00007f92c90c9800(0000) GS:ffff8e4dfdc00000(0000)
knlGS:0000000000000000
[  115.857531] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  115.858006] CR2: 0000000000000010 CR3: 0000000022f4c002 CR4: 00000000000706f0
[  115.858598] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  115.859393] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  115.860099] Call Trace:
[  115.860358]  <TASK>
[  115.860535]  propagate_mnt+0x14d/0x190
[  115.860848]  attach_recursive_mnt+0x274/0x3e0
[  115.861212]  path_mount+0x8c8/0xa60
[  115.861503]  __x64_sys_mount+0xf6/0x140
[  115.861819]  do_syscall_64+0x5b/0x80
[  115.862117]  ? do_faccessat+0x123/0x250
[  115.862435]  ? syscall_exit_to_user_mode+0x17/0x40
[  115.862826]  ? do_syscall_64+0x67/0x80
[  115.863133]  ? syscall_exit_to_user_mode+0x17/0x40
[  115.863527]  ? do_syscall_64+0x67/0x80
[  115.863835]  ? do_syscall_64+0x67/0x80
[  115.864144]  ? do_syscall_64+0x67/0x80
[  115.864452]  ? exc_page_fault+0x70/0x170
[  115.864775]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
[  115.865187] RIP: 0033:0x7f92c92b0ebe
[  115.865480] Code: 48 8b 0d 75 4f 0c 00 f7 d8 64 89 01 48 83 c8 ff
c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 49 89 ca b8 a5 00 00
00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 42 4f 0c 00 f7 d8 64 89
01 48
[  115.866984] RSP: 002b:00007fff000aa728 EFLAGS: 00000246 ORIG_RAX:
00000000000000a5
[  115.867607] RAX: ffffffffffffffda RBX: 000055a77888d6b0 RCX: 00007f92c92b0ebe
[  115.868240] RDX: 000055a77888d8e0 RSI: 000055a77888e6e0 RDI: 000055a77888e620
[  115.868823] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000001
[  115.869403] R10: 0000000000001000 R11: 0000000000000246 R12: 000055a77888e620
[  115.869994] R13: 000055a77888d8e0 R14: 00000000ffffffff R15: 00007f92c93e4076
[  115.870581]  </TASK>
[  115.870763] Modules linked in: nft_fib_inet nft_fib_ipv4
nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6
nft_reject nft_ct nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6
nf_defrag_ipv4 ip_set rfkill nf_tables nfnetlink qrtr snd_intel8x0
sunrpc snd_ac97_codec ac97_bus snd_pcm snd_timer intel_rapl_msr
intel_rapl_common snd vboxguest intel_powerclamp video rapl joydev
soundcore i2c_piix4 wmi fuse zram xfs vmwgfx crct10dif_pclmul
crc32_pclmul crc32c_intel polyval_clmulni polyval_generic
drm_ttm_helper ttm e1000 ghash_clmulni_intel serio_raw ata_generic
pata_acpi scsi_dh_rdac scsi_dh_emc scsi_dh_alua dm_multipath
[  115.875288] CR2: 0000000000000010
[  115.875641] ---[ end trace 0000000000000000 ]---
[  115.876135] RIP: 0010:propagate_one.part.0+0x7f/0x1a0
[  115.876551] Code: 75 eb 4c 8b 05 c2 25 37 02 4c 89 ca 48 8b 4a 10
49 39 d0 74 1e 48 3b 81 e0 00 00 00 74 26 48 8b 92 e0 00 00 00 be 01
00 00 00 <48> 8b 4a 10 49 39 d0 75 e2 40 84 f6 74 38 4c 89 05 84 25 37
02 4d
[  115.878086] RSP: 0018:ffffb8d5443d7d50 EFLAGS: 00010282
[  115.878511] RAX: ffff8e4d87c41c80 RBX: ffff8e4d88ded780 RCX: ffff8e4da4333a00
[  115.879128] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8e4d88ded780
[  115.879715] RBP: ffff8e4d88ded780 R08: ffff8e4da4338000 R09: ffff8e4da43388c0
[  115.880359] R10: 0000000000000002 R11: ffffb8d540158000 R12: ffffb8d5443d7da8
[  115.880962] R13: ffff8e4d88ded780 R14: 0000000000000000 R15: 0000000000000000
[  115.881548] FS:  00007f92c90c9800(0000) GS:ffff8e4dfdc00000(0000)
knlGS:0000000000000000
[  115.882234] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  115.882713] CR2: 0000000000000010 CR3: 0000000022f4c002 CR4: 00000000000706f0
[  115.883314] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  115.883966] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Fixes: f2ebb3a9 ("smarter propagate_mnt()")
Fixes: 5ec0811d ("propogate_mnt: Handle the first propogated copy being a slave")
Cc: <stable@vger.kernel.org>
Reported-by: Ditang Chen <ditang.c@gmail.com>
Signed-off-by: Seth Forshee (Digital Ocean) <sforshee@kernel.org>
Signed-off-by: Christian Brauner (Microsoft) <brauner@kernel.org>
---
If there are no big objections I'll get this to Linus rather sooner than later.

The build_skb might return a null pointer but there is no check on the
return value in the fec_enet_rx_queue(). So a null pointer dereference
might occur. To avoid this, we check the return value of build_skb. If
the return value is a null pointer, the driver will recycle the page and
update the statistic of ndev. Then jump to rx_processing_done to clear
the status flags of the BD so that the hardware can recycle the BD.

Fixes: 95698ff6 ("net: fec: using page pool to manage RX buffers")
Signed-off-by: Wei Fang <wei.fang@nxp.com>
Reviewed-by: Shenwei Wang <Shenwei.wang@nxp.com>
Reviewed-by: Alexander Duyck <alexanderduyck@fb.com>
Link: https://lore.kernel.org/r/20221219022755.1047573-1-wei.fang@nxp.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Pull m68knommu update from Greg Ungerer:
 "Only a single change to use the safer strscpy() instead of strncpy()
  when setting up the cmdline"

* tag 'm68knommu-for-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/gerg/m68knommu:
  m68k: use strscpy() to instead of strncpy()

Pull SPDX/License additions from Greg KH:
 "Here are two small updates for LICENSES and some kernel files that add
  the Copyleft-next license and use it in a SPDX tag as a dual-license
  for some kernel files.

  These have been discussed thoroughly in public on the linux-spdx
  mailing list, and have the needed acks on them, as well as having been
  in linux-next with no reported issues for quite some time"

* tag 'spdx-6.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
  testing: use the copyleft-next-0.3.1 SPDX tag
  LICENSES: Add the copyleft-next-0.3.1 license

Pull more devicetree updates from Rob Herring:
 "This is mostly a treewide clean-up from Krzysztof. There's also a
  couple of fixes and things that fell thru the cracks.

  I must say this has been a nice merge window without bindings dumped
  in at the last minute introducing warnings.

  Summary:

   - Treewide dropping of redundant 'binding' or 'schema' from schema
     titles. This will be followed up with a automated check to catch
     these.

   - Re-sort vendor-prefies

   - Convert GPIO based watchdog to schema

   - Handle all the variations for clocks, resets, power domains in i.MX
     PCIe binding

   - Document missing 'power-domains' property in mxsfb

   - Fix error with path references in Tegra XUSB example

   - Honor CONFIG_CMDLINE* even without /chosen node"

* tag 'devicetree-for-6.2-2' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  dt-bindings: drop redundant part of title (manual)
  dt-bindings: clock: drop redundant part of title
  dt-bindings: drop redundant part of title (beginning)
  dt-bindings: drop redundant part of title (end, part three)
  dt-bindings: drop redundant part of title (end, part two)
  dt-bindings: drop redundant part of title (end)
  dt-bindings: clock: st,stm32mp1-rcc: add proper title
  dt-bindings: memory-controllers: ti,gpmc-child: drop redundant part of title
  dt-bindings: drop redundant part of title of shared bindings
  dt-bindings: watchdog: gpio: Convert bindings to YAML
  dt-bindings: imx6q-pcie: Handle more resets on legacy platforms
  dt-bindings: imx6q-pcie: Handle various PD configurations
  dt-bindings: imx6q-pcie: Handle various clock configurations
  dt-bindings: hwmon: ntc-thermistor: drop Naveen Krishna Chatradhi from maintainers
  dt-bindings: mxsfb: Document i.MX8M/i.MX6SX/i.MX6SL power-domains property
  dt-bindings: vendor-prefixes: sort entries alphabetically
  dt-bindings: usb: tegra-xusb: Remove path references
  of: fdt: Honor CONFIG_CMDLINE* even without /chosen node

Pull parisc updates from Helge Deller:
 "There is one noteable patch, which allows the parisc kernel to use the
  same MADV_xxx constants as the other architectures going forward. With
  that change only alpha has one entry left (MADV_DONTNEED is 6 vs 4 on
  others) which is different. To prevent an ABI breakage, a wrapper is
  included which translates old MADV values to the new ones, so existing
  userspace isn't affected. Reason for that patch is, that some
  applications wrongly used the standard MADV_xxx values even on some
  non-x86 platforms and as such those programs failed to run correctly
  on parisc (examples are qemu-user, tor browser and boringssl).

  Then the kgdb console and the LED code received some fixes, and some
  0-day warnings are now gone. Finally, the very last compile warning
  which was visible during a kernel build is now fixed too (in the vDSO
  code).

  The majority of the patches are tagged for stable series and in
  summary this patchset is quite small and drops more code than it adds:

Fixes:
   - Fix potential null-ptr-deref in start_task()
   - Fix kgdb console on serial port
   - Add missing FORCE prerequisites in Makefile
   - Drop PMD_SHIFT from calculation in pgtable.h

  Enhancements:
   - Implement a wrapper to align madvise() MADV_* constants with other
     architectures
   - If machine supports running MPE/XL, show the MPE model string

  Cleanups:
   - Drop duplicate kgdb console code
   - Indenting fixes in setup_cmdline()"

* tag 'parisc-for-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Show MPE/iX model string at bootup
  parisc: Add missing FORCE prerequisites in Makefile
  parisc: Move pdc_result struct to firmware.c
  parisc: Drop locking in pdc console code
  parisc: Drop duplicate kgdb_pdc console
  parisc: Fix locking in pdc_iodc_print() firmware call
  parisc: Drop PMD_SHIFT from calculation in pgtable.h
  parisc: Align parisc MADV_XXX constants with all other architectures
  parisc: led: Fix potential null-ptr-deref in start_task()
  parisc: Fix inconsistent indenting in setup_cmdline()

Compiling this driver without setting "CONFIG_SONY_FF" generates the
following warning:

	drivers/hid/hid-sony.c:2358:20: warning: unused function
	'sony_send_output_report' [-Wunused-function]
	static inline void sony_send_output_report(struct sony_sc *sc)
	                   ^
	1 warning generated.

Add the missing preprocessor check to fix it.
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

I no longer work for Plantronics (aka Poly, aka HP) and do not have
access to the headsets in order to test. However, as noted by Maxim,
the other 32xx models that share the same base code set as the 3220
would need the same quirk. This patch adds the PIDs for the rest of
the Blackwire 32XX product family that require the quirk.

Plantronics Blackwire 3210 Series (047f:c055)
Plantronics Blackwire 3215 Series (047f:c057)
Plantronics Blackwire 3225 Series (047f:c058)

Quote from previous patch by Maxim Mikityanskiy
Plantronics Blackwire 3220 Series (047f:c056) sends HID reports twice
for each volume key press. This patch adds a quirk to hid-plantronics
for this product ID, which will ignore the second volume key press if
it happens within 5 ms from the last one that was handled.

The patch was tested on the mentioned model only, it shouldn't affect
other models, however, this quirk might be needed for them too.
Auto-repeat (when a key is held pressed) is not affected, because the
rate is about 3 times per second, which is far less frequent than once
in 5 ms.
End quote
Signed-off-by: Terry Junge <linuxhid@cosmicgizmosystems.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

The HID descriptor of this device contains two mouse collections, one
for mouse emulation and the other for the trackpoint.

Both collections get merged and, because the first one defines X and Y,
the movemenent events reported by the trackpoint collection are
ignored.

Set the MT_CLS_WIN_8_FORCE_MULTI_INPUT class for this device to be able
to receive its reports.

This fix is similar to/based on commit 40d5bb87 ("HID: multitouch:
enable multi-input as a quirk for some devices").

Link: https://gitlab.freedesktop.org/libinput/libinput/-/issues/825Reported-by: Akito <the@akito.ooo>
Tested-by: Akito <the@akito.ooo>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Battery status is reported for the HP Envy x360 eu0009nv stylus even
though it does not have battery.

Prevent it from always reporting the battery as low (1%).

Link: https://gitlab.freedesktop.org/libinput/libinput/-/issues/823Reported-by: Ioannis Iliopoulos <jxftw2424@gmail.com>
Tested-by: Ioannis Iliopoulos <jxftw2424@gmail.com>
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Pull asm-generic updates from Arnd Bergmann:
 "There are only three fairly simple patches.

  The #include change to linux/swab.h addresses a userspace build issue,
  and the change to the mmio tracing logic helps provide more useful
  traces"

* tag 'asm-generic-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  uapi: Add missing _UAPI prefix to <asm-generic/types.h> include guard
  asm-generic/io: Add _RET_IP_ to MMIO trace for more accurate debug info
  include/uapi/linux/swab: Fix potentially missing __always_inline

Some Wacom devices have a special "bootloader" mode that is used for
firmware flashing. When operating in this mode, the device cannot be
used for input, and the HID descriptor is not able to be processed by
the driver. The driver generates an "Unknown device_type" warning and
then returns an error code from wacom_probe(). This is a problem because
userspace still needs to be able to interact with the device via hidraw
to perform the firmware flash.

This commit adds a non-generic device definition for 056a:0094 which
is used when devices are in "bootloader" mode. It marks the devices
with a special BOOTLOADER type that is recognized by wacom_probe() and
wacom_raw_event(). When we see this type we ensure a hidraw device is
created and otherwise keep our hands off so that userspace is in full
control.
Signed-off-by: Jason Gerecke <jason.gerecke@wacom.com>
Tested-by: Tatsunosuke Tobita <tatsunosuke.tobita@wacom.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Add check for the return value of the dma_alloc_coherent since
it may return NULL pointer if allocation fails.

Fixes: 4b2c53d9 ("SFH:Transport Driver to add support of AMD Sensor Fusion Hub (SFH)")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Acked-by: Basavaraj Natikar <Basavaraj.Natikar@amd.com>
Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
Link: https://lore.kernel.org/r/20221220024921.21992-1-jiasheng@iscas.ac.cn

Convert the final two users of prandom_u32_max() that slipped in during
6.2-rc1 to use get_random_u32_below().

Then, with no more users left, we can finally remove the deprecated
function.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

Do not try to refresh the RNG seed in case the firmware does not support
setting variables.

This is specifically needed to prevent a NULL-pointer dereference on the
Lenovo X13s with some firmware revisions, or more generally, whenever
the runtime services have been disabled (e.g. efi=noruntime or with
PREEMPT_RT).

Fixes: e7b813b3 ("efi: random: refresh non-volatile random seed when RNG is initialized")
Reported-by: Steev Klimaszewski <steev@kali.org>
Reported-by: Bjorn Andersson <andersson@kernel.org>
Tested-by: Steev Klimaszewski <steev@kali.org>
Tested-by: Andrew Halaney <ahalaney@redhat.com> # sc8280xp-lenovo-thinkpad-x13s
Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

The <asm/archrandom.h> header is a random.c private detail, not
something to be called by other code. As such, don't make it
automatically available by way of random.h.

Cc: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Reviewed-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

Merge tag 'linux-can-fixes-for-6.2-20221219' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
pull-request: can 2022-12-19

The first patch is by Vincent Mailhol and adds the etas_es58x
devlink documentation to the index.

Haibo Chen's patch for the flexcan driver fixes a unbalanced
pm_runtime_enable warning.

The last patch is by me, targets the kvaser_usb driver and fixes
an error occurring with gcc-13.

* tag 'linux-can-fixes-for-6.2-20221219' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can:
  can: kvaser_usb: hydra: help gcc-13 to figure out cmd_len
  can: flexcan: avoid unbalanced pm_runtime_enable warning
  Documentation: devlink: add missing toc entry for etas_es58x devlink doc
====================

Link: https://lore.kernel.org/r/20221219155210.1143439-1-mkl@pengutronix.deSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Benjamin Coddington says:

====================
Stop corrupting socket's task_frag

The networking code uses flags in sk_allocation to determine if it can use
current->task_frag, however in-kernel users of sockets may stop setting
sk_allocation when they convert to the preferred memalloc_nofs_save/restore,
as SUNRPC has done in commit a1231fda ("SUNRPC: Set memalloc_nofs_save()
on all rpciod/xprtiod jobs").

This will cause corruption in current->task_frag when recursing into the
network layer for those subsystems during page fault or reclaim.  The
corruption is difficult to diagnose because stack traces may not contain the
offending subsystem at all.  The corruption is unlikely to show up in
testing because it requires memory pressure, and so subsystems that
convert to memalloc_nofs_save/restore are likely to continue to run into
this issue.

Previous reports and proposed fixes:
https://lore.kernel.org/netdev/96a18bd00cbc6cb554603cc0d6ef1c551965b078.1663762494.git.gnault@redhat.com/
https://lore.kernel.org/netdev/b4d8cb09c913d3e34f853736f3f5628abfd7f4b6.1656699567.git.gnault@redhat.com/
https://lore.kernel.org/linux-nfs/de6d99321d1dcaa2ad456b92b3680aa77c07a747.1665401788.git.gnault@redhat.com/

Guilluame Nault has done all of the hard work tracking this problem down and
finding the best fix for this issue.  I'm just taking a turn posting another
fix.
====================

Link: https://lore.kernel.org/r/cover.1671194454.git.bcodding@redhat.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Now that in-kernel socket users that may recurse during reclaim have benn
converted to sk_use_task_frag = false, we can have sk_page_frag() simply
check that value.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Since moving to memalloc_nofs_save/restore, SUNRPC has stopped setting the
GFP_NOIO flag on sk_allocation which the networking system uses to decide
when it is safe to use current->task_frag.  The results of this are
unexpected corruption in task_frag when SUNRPC is involved in memory
reclaim.

The corruption can be seen in crashes, but the root cause is often
difficult to ascertain as a crashing machine's stack trace will have no
evidence of being near NFS or SUNRPC code.  I believe this problem to
be much more pervasive than reports to the community may indicate.

Fix this by having kernel users of sockets that may corrupt task_frag due
to reclaim set sk_use_task_frag = false.  Preemptively correcting this
situation for users that still set sk_allocation allows them to convert to
memalloc_nofs_save/restore without the same unexpected corruptions that are
sure to follow, unlikely to show up in testing, and difficult to bisect.

CC: Philipp Reisner <philipp.reisner@linbit.com>
CC: Lars Ellenberg <lars.ellenberg@linbit.com>
CC: "Christoph Böhmwalder" <christoph.boehmwalder@linbit.com>
CC: Jens Axboe <axboe@kernel.dk>
CC: Josef Bacik <josef@toxicpanda.com>
CC: Keith Busch <kbusch@kernel.org>
CC: Christoph Hellwig <hch@lst.de>
CC: Sagi Grimberg <sagi@grimberg.me>
CC: Lee Duncan <lduncan@suse.com>
CC: Chris Leech <cleech@redhat.com>
CC: Mike Christie <michael.christie@oracle.com>
CC: "James E.J. Bottomley" <jejb@linux.ibm.com>
CC: "Martin K. Petersen" <martin.petersen@oracle.com>
CC: Valentina Manea <valentina.manea.m@gmail.com>
CC: Shuah Khan <shuah@kernel.org>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: David Howells <dhowells@redhat.com>
CC: Marc Dionne <marc.dionne@auristor.com>
CC: Steve French <sfrench@samba.org>
CC: Christine Caulfield <ccaulfie@redhat.com>
CC: David Teigland <teigland@redhat.com>
CC: Mark Fasheh <mark@fasheh.com>
CC: Joel Becker <jlbec@evilplan.org>
CC: Joseph Qi <joseph.qi@linux.alibaba.com>
CC: Eric Van Hensbergen <ericvh@gmail.com>
CC: Latchesar Ionkov <lucho@ionkov.net>
CC: Dominique Martinet <asmadeus@codewreck.org>
CC: Ilya Dryomov <idryomov@gmail.com>
CC: Xiubo Li <xiubli@redhat.com>
CC: Chuck Lever <chuck.lever@oracle.com>
CC: Jeff Layton <jlayton@kernel.org>
CC: Trond Myklebust <trond.myklebust@hammerspace.com>
CC: Anna Schumaker <anna@kernel.org>
CC: Steffen Klassert <steffen.klassert@secunet.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
Suggested-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Sockets that can be used while recursing into memory reclaim, like
those used by network block devices and file systems, mustn't use
current->task_frag: if the current process is already using it, then
the inner memory reclaim call would corrupt the task_frag structure.

To avoid this, sk_page_frag() uses ->sk_allocation to detect sockets
that mustn't use current->task_frag, assuming that those used during
memory reclaim had their allocation constraints reflected in
->sk_allocation.

This unfortunately doesn't cover all cases: in an attempt to remove all
usage of GFP_NOFS and GFP_NOIO, sunrpc stopped setting these flags in
->sk_allocation, and used memalloc_nofs critical sections instead.
This breaks the sk_page_frag() heuristic since the allocation
constraints are now stored in current->flags, which sk_page_frag()
can't read without risking triggering a cache miss and slowing down
TCP's fast path.

This patch creates a new field in struct sock, named sk_use_task_frag,
which sockets with memory reclaim constraints can set to false if they
can't safely use current->task_frag. In such cases, sk_page_frag() now
always returns the socket's page_frag (->sk_frag). The first user is
sunrpc, which needs to avoid using current->task_frag but can keep
->sk_allocation set to GFP_KERNEL otherwise.

Eventually, it might be possible to simplify sk_page_frag() by only
testing ->sk_use_task_frag and avoid relying on the ->sk_allocation
heuristic entirely (assuming other sockets will set ->sk_use_task_frag
according to their constraints in the future).

The new ->sk_use_task_frag field is placed in a hole in struct sock and
belongs to a cache line shared with ->sk_shutdown. Therefore it should
be hot and shouldn't have negative performance impacts on TCP's fast
path (sk_shutdown is tested just before the while() loop in
tcp_sendmsg_locked()).

Link: https://lore.kernel.org/netdev/b4d8cb09c913d3e34f853736f3f5628abfd7f4b6.1656699567.git.gnault@redhat.com/Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The unregister check could be incorrectly triggered if a netdev
changes its type after register. That is possible for a tun device
using TUNSETLINK ioctl, resulting in mctp unregister failing
and the netdev unregister waiting forever.

This was encountered by https://github.com/openthread/openthread/issues/8523

Neither check at register or unregister is required. They were added in
an attempt to track down mctp_ptr being set unexpectedly, which should
not happen in normal operation.

Fixes: 7b1871af ("mctp: Warn if pointer is set for a wrong dev type")
Signed-off-by: Matt Johnston <matt@codeconstruct.com.au>
Link: https://lore.kernel.org/r/20221215054933.2403401-1-matt@codeconstruct.com.auSigned-off-by: Jakub Kicinski <kuba@kernel.org>

KSZ swithes used interrupts for detecting the phy link up and down.
During registering the interrupt handler, it used IRQF_TRIGGER_FALLING
flag. But this flag has to be retrieved from device tree instead of hard
coding in the driver, so removing the flag.

Fixes: ff319a64 ("net: dsa: microchip: move interrupt handling logic from lan937x to ksz_common")
Reported-by: Christian Eggers <ceggers@arri.de>
Signed-off-by: Arun Ramadoss <arun.ramadoss@microchip.com>
Link: https://lore.kernel.org/r/20221213101440.24667-1-arun.ramadoss@microchip.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Pull ARM SoC fixes from Arnd Bergmann:
 "These are a couple of build fixes from randconfig testing, plus a set
  of Mediatek SoC specific fixes, all trivial"

* tag 'soc-fixes-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
  soc: tegra: fix CPU_BIG_ENDIAN dependencies
  ARM: disallow pre-ARMv5 builds with ld.lld
  ARM: pxa: fix building with clang
  MAINTAINERS: add related dts to IXP4xx
  ARM: dts: spear: drop 0x from unit address
  arm64: dts: mt8183: Fix Mali GPU clock
  arm64: dts: mediatek: mt8195-demo: fix the memory size of node secmon
  soc: mediatek: pm-domains: Fix the power glitch issue

Pull Kbuild updates from Masahiro Yamada:

 - Support zstd-compressed debug info

 - Allow W=1 builds to detect objects shared among multiple modules

 - Add srcrpm-pkg target to generate a source RPM package

 - Make the -s option detection work for future GNU Make versions

 - Add -Werror to KBUILD_CPPFLAGS when CONFIG_WERROR=y

 - Allow W=1 builds to detect -Wundef warnings in any preprocessed files

 - Raise the minimum supported version of binutils to 2.25

 - Use $(intcmp ...) to compare integers if GNU Make >= 4.4 is used

 - Use $(file ...) to read a file if GNU Make >= 4.2 is used

 - Print error if GNU Make older than 3.82 is used

 - Allow modpost to detect section mismatches with Clang LTO

 - Include vmlinuz.efi into kernel tarballs for arm64 CONFIG_EFI_ZBOOT=y

* tag 'kbuild-v6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild: (29 commits)
  buildtar: fix tarballs with EFI_ZBOOT enabled
  modpost: Include '.text.*' in TEXT_SECTIONS
  padata: Mark padata_work_init() as __ref
  kbuild: ensure Make >= 3.82 is used
  kbuild: refactor the prerequisites of the modpost rule
  kbuild: change module.order to list *.o instead of *.ko
  kbuild: use .NOTINTERMEDIATE for future GNU Make versions
  kconfig: refactor Makefile to reduce process forks
  kbuild: add read-file macro
  kbuild: do not sort after reading modules.order
  kbuild: add test-{ge,gt,le,lt} macros
  Documentation: raise minimum supported version of binutils to 2.25
  kbuild: add -Wundef to KBUILD_CPPFLAGS for W=1 builds
  kbuild: move -Werror from KBUILD_CFLAGS to KBUILD_CPPFLAGS
  kbuild: Port silent mode detection to future gnu make.
  init/version.c: remove #include <generated/utsrelease.h>
  firmware_loader: remove #include <generated/utsrelease.h>
  modpost: Mark uuid_le type to be suitable only for MEI
  kbuild: add ability to make source rpm buildable using koji
  kbuild: warn objects shared among multiple modules
  ...