For inline assembly, we place exception fixups out-of-line in the
`.fixup` section such that these are out of the way of the fast path.
This has a few drawbacks:

* Since the fixup code is anonymous, backtraces will symbolize fixups as
  offsets from the nearest prior symbol, currently
  `__entry_tramp_text_end`. This is confusing, and painful to debug
  without access to the relevant vmlinux.

* Since the exception handler adjusts the PC to execute the fixup, and
  the fixup uses a direct branch back into the function it fixes,
  backtraces of fixups miss the original function. This is confusing,
  and violates requirements for RELIABLE_STACKTRACE (and therefore
  LIVEPATCH).

* Inline assembly and associated fixups are generated from templates,
  and we have many copies of logically identical fixups which only
  differ in which specific registers are written to and which address is
  branched to at the end of the fixup. This is potentially wasteful of
  I-cache resources, and makes it hard to add additional logic to fixups
  without significant bloat.

* In the case of load_unaligned_zeropad(), the logic in the fixup
  requires a temporary register that we must allocate even in the
  fast-path where it will not be used.

This patch address all four concerns for load_unaligned_zeropad() fixups
by adding a dedicated exception handler which performs the fixup logic
in exception context and subsequent returns back after the faulting
instruction. For the moment, the fixup logic is identical to the old
assembly fixup logic, but in future we could enhance this by taking the
ESR and FAR into account to constrain the faults we try to fix up, or to
specialize fixups for MTE tag check faults.

Other than backtracing, there should be no functional change as a result
of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-13-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

For inline assembly, we place exception fixups out-of-line in the
`.fixup` section such that these are out of the way of the fast path.
This has a few drawbacks:

* Since the fixup code is anonymous, backtraces will symbolize fixups as
  offsets from the nearest prior symbol, currently
  `__entry_tramp_text_end`. This is confusing, and painful to debug
  without access to the relevant vmlinux.

* Since the exception handler adjusts the PC to execute the fixup, and
  the fixup uses a direct branch back into the function it fixes,
  backtraces of fixups miss the original function. This is confusing,
  and violates requirements for RELIABLE_STACKTRACE (and therefore
  LIVEPATCH).

* Inline assembly and associated fixups are generated from templates,
  and we have many copies of logically identical fixups which only
  differ in which specific registers are written to and which address is
  branched to at the end of the fixup. This is potentially wasteful of
  I-cache resources, and makes it hard to add additional logic to fixups
  without significant bloat.

This patch address all three concerns for inline uaccess fixups by
adding a dedicated exception handler which updates registers in
exception context and subsequent returns back into the function which
faulted, removing the need for fixups specialized to each faulting
instruction.

Other than backtracing, there should be no functional change as a result
of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-12-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

Subsequent patches will add specialized handlers for fixups, in addition
to the simple PC fixup and BPF handlers we have today. In preparation,
this patch adds a new `type` field to struct exception_table_entry, and
uses this to distinguish the fixup and BPF cases. A `data` field is also
added so that subsequent patches can associate data specific to each
exception site (e.g. register numbers).

Handlers are named ex_handler_*() for consistency, following the exmaple
of x86. At the same time, get_ex_fixup() is split out into a helper so
that it can be used by other ex_handler_*() functions ins subsequent
patches.

This patch will increase the size of the exception tables, which will be
remedied by subsequent patches removing redundant fixup code. There
should be no functional change as a result of this patch.

Since each entry is now 12 bytes in size, we must reduce the alignment
of each entry from `.align 3` (i.e. 8 bytes) to `.align 2` (i.e. 4
bytes), which is the natrual alignment of the `insn` and `fixup` fields.
The current 8-byte alignment is a holdover from when the `insn` and
`fixup` fields was 8 bytes, and while not harmful has not been necessary
since commit:

  6c94f27a ("arm64: switch to relative exception tables")

Similarly, RO_EXCEPTION_TABLE_ALIGN is dropped to 4 bytes.

Concurrently with this patch, x86's exception table entry format is
being updated (similarly to a 12-byte format, with 32-bytes of absolute
data). Once both have been merged it should be possible to unify the
sorttable logic for the two.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: James Morse <james.morse@arm.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-11-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

Subsequent patches will extend `struct exception_table_entry` with more
fields, and the distinction between the entry and its `fixup` field will
become more important.

For clarity, let's consistently use `ex` to refer to refer to an entire
entry. In subsequent patches we'll use `fixup` to refer to the fixup
field specifically. This matches the naming convention used today in
arch/arm64/net/bpf_jit_comp.c.

There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-10-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

The return values of fixup_exception() and arm64_bpf_fixup_exception()
represent a boolean condition rather than an error code, so for clarity
it would be better to return `bool` rather than `int`.

This patch adjusts the code accordingly. While we're modifying the
prototype, we also remove the unnecessary `extern` keyword, so that this
won't look out of place when we make subsequent additions to the header.

There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: James Morse <james.morse@arm.com>
Cc: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-9-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

In subsequent patches we'll alter the structure and usage of struct
exception_table_entry. For inline assembly, we create these using the
`_ASM_EXTABLE()` CPP macro defined in <asm/uaccess.h>, and for plain
assembly code we use the `_asm_extable()` GAS macro defined in
<asm/assembler.h>, which are largely identical save for different
escaping and stringification requirements.

This patch moves the common definitions to a new <asm/asm-extable.h>
header, so that it's easier to keep the two in-sync, and to remove the
implication that these are only used for uaccess helpers (as e.g.
load_unaligned_zeropad() is only used on kernel memory, and depends upon
`_ASM_EXTABLE()`.

At the same time, a few minor modifications are made for clarity and in
preparation for subsequent patches:

* The structure creation is factored out into an `__ASM_EXTABLE_RAW()`
  macro. This will make it easier to support different fixup variants in
  subsequent patches without needing to update all users of
  `_ASM_EXTABLE()`, and makes it easier to see tha the CPP and GAS
  variants of the macros are structurally identical.

  For the CPP macro, the stringification of fields is left to the
  wrapper macro, `_ASM_EXTABLE()`, as in subsequent patches it will be
  necessary to stringify fields in wrapper macros to safely concatenate
  strings which cannot be token-pasted together in CPP.

* The fields of the structure are created separately on their own lines.
  This will make it easier to add/remove/modify individual fields
  clearly.

* Additional parentheses are added around the use of macro arguments in
  field definitions to avoid any potential problems with evaluation due
  to operator precedence, and to make errors upon misuse clearer.

* USER() is moved into <asm/asm-uaccess.h>, as it is not required by all
  assembly code, and is already refered to by comments in that file.

There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-8-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

In subsequent patches we'll want to map W registers to their register
numbers. Update gpr-num.h so that we can do this.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-7-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

In <asm/sysreg.h> we have macros to convert the names of general purpose
registers (GPRs) into integer constants, which we use to manually build
the encoding for `MRS` and `MSR` instructions where we can't rely on the
assembler to do so for us.

In subsequent patches we'll need to map the same GPR names to integer
constants so that we can use this to build metadata for exception
fixups.

So that the we can use the mappings elsewhere, factor out the
definitions into a new <asm/gpr-num.h> header, renaming the definitions
to align with this "GPR num" naming for clarity.

There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-6-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

In subsequent patches we'll alter `struct exception_table_entry`, adding
fields that are not needed for KVM exception fixups.

In preparation for this, migrate KVM to its own `struct
kvm_exception_table_entry`, which is identical to the current format of
`struct exception_table_entry`. Comments are updated accordingly.

There should be no functional change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Alexandru Elisei <alexandru.elisei@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Cc: Will Deacon <will@kernel.org>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-5-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

Like other functions, __arch_copy_to_user() places its exception fixups
in the `.fixup` section without any clear association with
__arch_copy_to_user() itself. If we backtrace the fixup code, it will be
symbolized as an offset from the nearest prior symbol, which happens to
be `__entry_tramp_text_end`. Further, since the PC adjustment for the
fixup is akin to a direct branch rather than a function call,
__arch_copy_to_user() itself will be missing from the backtrace.

This is confusing and hinders debugging. In general this pattern will
also be problematic for CONFIG_LIVEPATCH, since fixups often return to
their associated function, but this isn't accurately captured in the
stacktrace.

To solve these issues for assembly functions, we must move fixups into
the body of the functions themselves, after the usual fast-path returns.
This patch does so for __arch_copy_to_user().

Inline assembly will be dealt with in subsequent patches.

Other than the improved backtracing, there should be no functional
change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-4-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

Like other functions, __arch_copy_from_user() places its exception
fixups in the `.fixup` section without any clear association with
__arch_copy_from_user() itself. If we backtrace the fixup code, it will
be symbolized as an offset from the nearest prior symbol, which happens
to be `__entry_tramp_text_end`. Further, since the PC adjustment for the
fixup is akin to a direct branch rather than a function call,
__arch_copy_from_user() itself will be missing from the backtrace.

This is confusing and hinders debugging. In general this pattern will
also be problematic for CONFIG_LIVEPATCH, since fixups often return to
their associated function, but this isn't accurately captured in the
stacktrace.

To solve these issues for assembly functions, we must move fixups into
the body of the functions themselves, after the usual fast-path returns.
This patch does so for __arch_copy_from_user().

Inline assembly will be dealt with in subsequent patches.

Other than the improved backtracing, there should be no functional
change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-3-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

Like other functions, __arch_clear_user() places its exception fixups in
the `.fixup` section without any clear association with
__arch_clear_user() itself. If we backtrace the fixup code, it will be
symbolized as an offset from the nearest prior symbol, which happens to
be `__entry_tramp_text_end`. Further, since the PC adjustment for the
fixup is akin to a direct branch rather than a function call,
__arch_clear_user() itself will be missing from the backtrace.

This is confusing and hinders debugging. In general this pattern will
also be problematic for CONFIG_LIVEPATCH, since fixups often return to
their associated function, but this isn't accurately captured in the
stacktrace.

To solve these issues for assembly functions, we must move fixups into
the body of the functions themselves, after the usual fast-path returns.
This patch does so for __arch_clear_user().

Inline assembly will be dealt with in subsequent patches.

Other than the improved backtracing, there should be no functional
change as a result of this patch.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Mark Brown <broonie@kernel.org>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20211019160219.5202-2-mark.rutland@arm.comSigned-off-by: Will Deacon <will@kernel.org>

Pull ksmbd fixes from Steve French:
 "Five fixes for the ksmbd kernel server, including three security
  fixes:

   - remove follow symlinks support

   - use LOOKUP_BENEATH to prevent out of share access

   - SMB3 compounding security fix

   - fix for returning the default streams correctly, fixing a bug when
     writing ppt or doc files from some clients

   - logging more clearly that ksmbd is experimental (at module load
     time)"

* tag '5.15-rc2-ksmbd-fixes' of git://git.samba.org/ksmbd:
  ksmbd: use LOOKUP_BENEATH to prevent the out of share access
  ksmbd: remove follow symlinks support
  ksmbd: check protocol id in ksmbd_verify_smb_message()
  ksmbd: add default data stream name in FILE_STREAM_INFORMATION
  ksmbd: log that server is experimental at module load

Pull EDAC fixes from Borislav Petkov:
 "Fix two EDAC drivers using the wrong value type for the DIMM mode"

* tag 'edac_urgent_for_v5.15_rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/ras/ras:
  EDAC/dmc520: Assign the proper type to dimm->edac_mode
  EDAC/synopsys: Fix wrong value type assignment for edac_mode

Pull thermal fixes from Daniel Lezcano:

 - Fix thermal shutdown after a suspend/resume due to a wrong TCC value
   restored on Intel platform (Antoine Tenart)

 - Fix potential buffer overflow when building the list of policies. The
   buffer size is not updated after writing to it (Dan Carpenter)

 - Fix wrong check against IS_ERR instead of NULL (Ansuel Smith)

* tag 'thermal-v5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/thermal/linux:
  thermal/drivers/tsens: Fix wrong check for tzd in irq handlers
  thermal/core: Potential buffer overflow in thermal_build_list_of_policies()
  thermal/drivers/int340x: Do not set a wrong tcc offset on resume

Pull x86 fixes from Thomas Gleixner:
 "A set of fixes for X86:

   - Prevent sending the wrong signal when protection keys are enabled
     and the kernel handles a fault in the vsyscall emulation.

   - Invoke early_reserve_memory() before invoking e820_memory_setup()
     which is required to make the Xen dom0 e820 hooks work correctly.

   - Use the correct data type for the SETZ operand in the EMQCMDS
     instruction wrapper.

   - Prevent undefined behaviour to the potential unaligned accesss in
     the instruction decoder library"

* tag 'x86-urgent-2021-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/insn, tools/x86: Fix undefined behavior due to potential unaligned accesses
  x86/asm: Fix SETZ size enqcmds() build failure
  x86/setup: Call early_reserve_memory() earlier
  x86/fault: Fix wrong signal when vsyscall fails with pkey

Pull timer fix from Thomas Gleixner:
 "A single fix for the recently introduced regression in posix CPU
  timers which failed to stop the timer when requested. That caused
  unexpected signals to be sent to the process/thread causing
  malfunction"

* tag 'timers-urgent-2021-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  posix-cpu-timers: Prevent spuriously armed 0-value itimer

Pull irq fixes from Thomas Gleixner:
 "A set of fixes for interrupt chip drivers:

   - Work around a bad GIC integration on a Renesas platform which can't
     handle byte-sized MMIO access

   - Plug a potential memory leak in the GICv4 driver

   - Fix a regression in the Armada 370-XP IPI code which was caused by
     issuing EOI instack of ACK.

   - A couple of small fixes here and there"

* tag 'irq-urgent-2021-09-26' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/gic: Work around broken Renesas integration
  irqchip/renesas-rza1: Use semicolons instead of commas
  irqchip/gic-v3-its: Fix potential VPE leak on error
  irqchip/goldfish-pic: Select GENERIC_IRQ_CHIP to fix build
  irqchip/mbigen: Repair non-kernel-doc notation
  irqdomain: Change the type of 'size' in __irq_domain_add() to be consistent
  irqchip/armada-370-xp: Fix ack/eoi breakage
  Documentation: Fix irq-domain.rst build warning

Merge misc fixes from Andrew Morton:
 "16 patches.

  Subsystems affected by this patch series: xtensa, sh, ocfs2, scripts,
  lib, and mm (memory-failure, kasan, damon, shmem, tools, pagecache,
  debug, and pagemap)"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm: fix uninitialized use in overcommit_policy_handler
  mm/memory_failure: fix the missing pte_unmap() call
  kasan: always respect CONFIG_KASAN_STACK
  sh: pgtable-3level: fix cast to pointer from integer of different size
  mm/debug: sync up latest migrate_reason to migrate_reason_names
  mm/debug: sync up MR_CONTIG_RANGE and MR_LONGTERM_PIN
  mm: fs: invalidate bh_lrus for only cold path
  lib/zlib_inflate/inffast: check config in C to avoid unused function warning
  tools/vm/page-types: remove dependency on opt_file for idle page tracking
  scripts/sorttable: riscv: fix undeclared identifier 'EM_RISCV' error
  ocfs2: drop acl cache for directories too
  mm/shmem.c: fix judgment error in shmem_is_huge()
  xtensa: increase size of gcc stack frame check
  mm/damon: don't use strnlen() with known-bogus source length
  kasan: fix Kconfig check of CC_HAS_WORKING_NOSANITIZE_ADDRESS
  mm, hwpoison: add is_free_buddy_page() in HWPoisonHandlable()

Pull SCSI fixes from James Bottomley:
 "Thirty-three fixes, I'm afraid.

  Essentially the build up from the last couple of weeks while I've been
  dealling with Linux Plumbers conference infrastructure issues. It's
  mostly the usual assortment of spelling fixes and minor corrections.

  The only core relevant changes are to the sd driver to reduce the spin
  up message spew and fix a small memory leak on the freeing path"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (33 commits)
  scsi: ses: Retry failed Send/Receive Diagnostic commands
  scsi: target: Fix spelling mistake "CONFLIFT" -> "CONFLICT"
  scsi: lpfc: Fix gcc -Wstringop-overread warning, again
  scsi: lpfc: Use correct scnprintf() limit
  scsi: lpfc: Fix sprintf() overflow in lpfc_display_fpin_wwpn()
  scsi: core: Remove 'current_tag'
  scsi: acornscsi: Remove tagged queuing vestiges
  scsi: fas216: Kill scmd->tag
  scsi: qla2xxx: Restore initiator in dual mode
  scsi: ufs: core: Unbreak the reset handler
  scsi: sd_zbc: Support disks with more than 2**32 logical blocks
  scsi: ufs: core: Revert "scsi: ufs: Synchronize SCSI and UFS error handling"
  scsi: bsg: Fix device unregistration
  scsi: sd: Make sd_spinup_disk() less noisy
  scsi: ufs: ufs-pci: Fix Intel LKF link stability
  scsi: mpt3sas: Clean up some inconsistent indenting
  scsi: megaraid: Clean up some inconsistent indenting
  scsi: sr: Fix spelling mistake "does'nt" -> "doesn't"
  scsi: Remove SCSI CDROM MAINTAINERS entry
  scsi: megaraid: Fix Coccinelle warning
  ...

Pull io_uring fixes from Jens Axboe:
 "This one looks a bit bigger than it is, but that's mainly because 2/3
  of it is enabling IORING_OP_CLOSE to close direct file descriptors.

  We've had a few folks using them and finding it confusing that the way
  to close them is through using -1 for file update, this just brings
  API symmetry for direct descriptors. Hence I think we should just do
  this now and have a better API for 5.15 release. There's some room for
  de-duplicating the close code, but we're leaving that for the next
  merge window.

  Outside of that, just small fixes:

   - Poll race fixes (Hao)

   - io-wq core dump exit fix (me)

   - Reschedule around potentially intensive tctx and buffer iterators
     on teardown (me)

   - Fix for always ending up punting files update to io-wq (me)

   - Put the provided buffer meta data under memcg accounting (me)

   - Tweak for io_write(), removing dead code that was added with the
     iterator changes in this release (Pavel)"

* tag 'io_uring-5.15-2021-09-25' of git://git.kernel.dk/linux-block:
  io_uring: make OP_CLOSE consistent with direct open
  io_uring: kill extra checks in io_write()
  io_uring: don't punt files update to io-wq unconditionally
  io_uring: put provided buffer meta data under memcg accounting
  io_uring: allow conditional reschedule for intensive iterators
  io_uring: fix potential req refcount underflow
  io_uring: fix missing set of EPOLLONESHOT for CQ ring overflow
  io_uring: fix race between poll completion and cancel_hash insertion
  io-wq: ensure we exit if thread group is exiting

Pull block fixes from Jens Axboe:

 - NVMe pull request via Christoph:
      - keep ctrl->namespaces ordered (Christoph Hellwig)
      - fix incorrect h2cdata pdu offset accounting in nvme-tcp (Sagi
        Grimberg)
      - handled updated hw_queues in nvme-fc more carefully (Daniel
        Wagner, James Smart)

 - md lock order fix (Christoph)

 - fallocate locking fix (Ming)

 - blktrace UAF fix (Zhihao)

 - rq-qos bio tracking fix (Ming)

* tag 'block-5.15-2021-09-25' of git://git.kernel.dk/linux-block:
  block: hold ->invalidate_lock in blkdev_fallocate
  blktrace: Fix uaf in blk_trace access after removing by sysfs
  block: don't call rq_qos_ops->done_bio if the bio isn't tracked
  md: fix a lock order reversal in md_alloc
  nvme: keep ctrl->namespaces ordered
  nvme-tcp: fix incorrect h2cdata pdu offset accounting
  nvme-fc: remove freeze/unfreeze around update_nr_hw_queues
  nvme-fc: avoid race between time out and tear down
  nvme-fc: update hardware queues before using them

Pull xen fixes from Juergen Gross:
 "Some minor cleanups and fixes of some theoretical bugs, as well as a
  fix of a bug introduced in 5.15-rc1"

* tag 'for-linus-5.15b-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/x86: fix PV trap handling on secondary processors
  xen/balloon: fix balloon kthread freezing
  swiotlb-xen: this is PV-only on x86
  xen/pci-swiotlb: reduce visibility of symbols
  PCI: only build xen-pcifront in PV-enabled environments
  swiotlb-xen: ensure to issue well-formed XENMEM_exchange requests
  Xen/gntdev: don't ignore kernel unmapping error
  xen/x86: drop redundant zeroing from cpu_initialize_context()

Merge tag 'linux-kselftest-fixes-5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest

Pull Kselftest fixes from Shuah Khan:

 - fix to Kselftest common framework header install to run before other
   targets for it work correctly in parallel build case.

 - fixes to kvm test to not ignore fscanf() returns which could result
   in inconsistent test behavior and failures.

* tag 'linux-kselftest-fixes-5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  selftests: kvm: fix get_run_delay() ignoring fscanf() return warn
  selftests: kvm: move get_run_delay() into lib/test_util
  selftests:kvm: fix get_trans_hugepagesz() ignoring fscanf() return warn
  selftests:kvm: fix get_warnings_count() ignoring fscanf() return warn
  selftests: be sure to make khdr before other targets

Pull erofs fixes from Gao Xiang:
 "Two bugfixes to fix the 4KiB blockmap chunk format availability and a
  dangling pointer usage. There is also a trivial cleanup to clarify
  compacted_2b if compacted_4b_initial > totalidx.

  Summary:

   - fix the dangling pointer use in erofs_lookup tracepoint

   - fix unsupported chunk format check

   - zero out compacted_2b if compacted_4b_initial > totalidx"

* tag 'erofs-for-5.15-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  erofs: clear compacted_2b if compacted_4b_initial > totalidx
  erofs: fix misbehavior of unsupported chunk format check
  erofs: fix up erofs_lookup tracepoint

Pull cifs fixes from Steve French:
 "Six small cifs/smb3 fixes, two for stable:

   - important fix for deferred close (found by a git functional test)
     related to attribute caching on close.

   - four (two cosmetic, two more serious) small fixes for problems
     pointed out by smatch via Dan Carpenter

   - fix for comment formatting problems pointed out by W=1"

* tag '5.15-rc2-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  cifs: fix incorrect check for null pointer in header_assemble
  smb3: correct server pointer dereferencing check to be more consistent
  smb3: correct smb3 ACL security descriptor
  cifs: Clear modified attribute bit from inode flags
  cifs: Deal with some warnings from W=1
  cifs: fix a sign extension bug

Pull char/misc driver fixes from Greg KH:
 "Here are some small char and misc driver fixes for 5.15-rc3.

  Nothing huge in here, just fixes for a number of small issues that
  have been reported. These include:

   - habanalabs race conditions and other bugs fixed

   - binder driver fixes

   - fpga driver fixes

   - coresight build warning fix

   - nvmem driver fix

   - comedi memory leak fix

   - bcm-vk tty race fix

   - other tiny driver fixes

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'char-misc-5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (21 commits)
  comedi: Fix memory leak in compat_insnlist()
  nvmem: NVMEM_NINTENDO_OTP should depend on WII
  misc: bcm-vk: fix tty registration race
  fpga: dfl: Avoid reads to AFU CSRs during enumeration
  fpga: machxo2-spi: Fix missing error code in machxo2_write_complete()
  fpga: machxo2-spi: Return an error on failure
  habanalabs: expose a single cs seq in staged submissions
  habanalabs: fix wait offset handling
  habanalabs: rate limit multi CS completion errors
  habanalabs/gaudi: fix LBW RR configuration
  habanalabs: Fix spelling mistake "FEADBACK" -> "FEEDBACK"
  habanalabs: fail collective wait when not supported
  habanalabs/gaudi: use direct MSI in single mode
  habanalabs: fix kernel OOPs related to staged cs
  habanalabs: fix potential race in interrupt wait ioctl
  mcb: fix error handling in mcb_alloc_bus()
  misc: genwqe: Fixes DMA mask setting
  coresight: syscfg: Fix compiler warning
  nvmem: core: Add stubs for nvmem_cell_read_variable_le_u32/64 if !CONFIG_NVMEM
  binder: make sure fd closes complete
  ...

Pull staging driver fixes from Greg KH:
 "Here are two small staging driver fixes for 5.15-rc3:

   - greybus tty use-after-free bugfix

   - r8188eu ioctl overlap build warning fix

  Note, the r8188eu ioctl has been entirely removed for 5.16-rc1, but
  it's good to get this fixed now for people using this in 5.15.

  Both of these have been in linux-next for a while with no reported
  issues"

* tag 'staging-5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging:
  staging: r8188eu: fix -Wrestrict warnings
  staging: greybus: uart: fix tty use after free

Pull tty/serial fixes from Greg KH:
 "Here are four small tty/serial driver fixes for 5.15-rc3. They
  include:

   - remove an export now that no one is using it anymore

   - mvebu-uart tx_empty callback fix

   - 8250_omap bugfix

   - synclink_gt build fix

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: unexport tty_ldisc_release
  tty: synclink_gt: rename a conflicting function name
  serial: mvebu-uart: fix driver's tx_empty callback
  serial: 8250: 8250_omap: Fix RX_LVL register offset

Pull USB driver fixes from Greg KH:
 "Here are some USB driver fixes and new device ids for 5.15-rc3.

  They include:

   - usb-storage quirk additions

   - usb-serial new device ids

   - usb-serial driver fixes

   - USB roothub registration bugfix to resolve a long-reported issue

   - usb gadget driver fixes for a large number of small things

   - dwc2 driver fixes

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'usb-5.15-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb: (28 commits)
  USB: serial: option: add device id for Foxconn T99W265
  USB: serial: cp210x: add ID for GW Instek GDM-834x Digital Multimeter
  USB: serial: cp210x: add part-number debug printk
  USB: serial: cp210x: fix dropped characters with CP2102
  MAINTAINERS: usb, update Peter Korsgaard's entries
  usb: musb: tusb6010: uninitialized data in tusb_fifo_write_unaligned()
  usb-storage: Add quirk for ScanLogic SL11R-IDE older than 2.6c
  Re-enable UAS for LaCie Rugged USB3-FW with fk quirk
  USB: serial: option: remove duplicate USB device ID
  USB: serial: mos7840: remove duplicated 0xac24 device ID
  arm64: dts: qcom: ipq8074: remove USB tx-fifo-resize property
  usb: gadget: f_uac2: Populate SS descriptors' wBytesPerInterval
  usb: gadget: f_uac2: Add missing companion descriptor for feedback EP
  usb: dwc2: gadget: Fix ISOC transfer complete handling for DDMA
  usb: core: hcd: Modularize HCD stop configuration in usb_stop_hcd()
  xhci: Set HCD flag to defer primary roothub registration
  usb: core: hcd: Add support for deferring roothub registration
  usb: dwc2: gadget: Fix ISOC flow for BDMA and Slave
  usb: dwc3: core: balance phy init and exit
  Revert "USB: bcma: Add a check for devm_gpiod_get"
  ...

instead of removing '..' in a given path, call
kern_path with LOOKUP_BENEATH flag to prevent
the out of share access.

ran various test on this:
smb2-cat-async smb://127.0.0.1/homes/../out_of_share
smb2-cat-async smb://127.0.0.1/homes/foo/../../out_of_share
smbclient //127.0.0.1/homes -c "mkdir ../foo2"
smbclient //127.0.0.1/homes -c "rename bar ../bar"

Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: Ralph Boehme <slow@samba.org>
Tested-by: Steve French <smfrench@gmail.com>
Tested-by: Namjae Jeon <linkinjeon@kernel.org>
Acked-by: Namjae Jeon <linkinjeon@kernel.org>
Signed-off-by: Hyunchul Lee <hyc.lee@gmail.com>
Signed-off-by: Steve French <stfrench@microsoft.com>

We get an unexpected value of /proc/sys/vm/overcommit_memory after
running the following program:

  int main()
  {
      int fd = open("/proc/sys/vm/overcommit_memory", O_RDWR);
      write(fd, "1", 1);
      write(fd, "2", 1);
      close(fd);
  }

write(fd, "2", 1) will pass *ppos = 1 to proc_dointvec_minmax.
proc_dointvec_minmax will return 0 without setting new_policy.

  t.data = &new_policy;
  ret = proc_dointvec_minmax(&t, write, buffer, lenp, ppos)
      -->do_proc_dointvec
         -->__do_proc_dointvec
              if (write) {
                if (proc_first_pos_non_zero_ignore(ppos, table))
                  goto out;

  sysctl_overcommit_memory = new_policy;

so sysctl_overcommit_memory will be set to an uninitialized value.

Check whether new_policy has been changed by proc_dointvec_minmax.

Link: https://lkml.kernel.org/r/20210923020524.13289-1-chenjun102@huawei.com
Fixes: 56f3547b ("mm: adjust vm_committed_as_batch according to vm overcommit policy")
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Feng Tang <feng.tang@intel.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Rui Xiang <rui.xiang@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The paired pte_unmap() call is missing before the
dev_pagemap_mapping_shift() returns.  So fix it.

David says:
 "I guess this code never runs on 32bit / highmem, that's why we didn't
  notice so far".

[akpm@linux-foundation.org: cleanup]

Link: https://lkml.kernel.org/r/20210923122642.4999-1-zhengqi.arch@bytedance.comSigned-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently, the asan-stack parameter is only passed along if
CFLAGS_KASAN_SHADOW is not empty, which requires KASAN_SHADOW_OFFSET to
be defined in Kconfig so that the value can be checked.  In RISC-V's
case, KASAN_SHADOW_OFFSET is not defined in Kconfig, which means that
asan-stack does not get disabled with clang even when CONFIG_KASAN_STACK
is disabled, resulting in large stack warnings with allmodconfig:

  drivers/video/fbdev/omap2/omapfb/displays/panel-lgphilips-lb035q02.c:117:12: error: stack frame size (14400) exceeds limit (2048) in function 'lb035q02_connect' [-Werror,-Wframe-larger-than]
  static int lb035q02_connect(struct omap_dss_device *dssdev)
             ^
  1 error generated.

Ensure that the value of CONFIG_KASAN_STACK is always passed along to
the compiler so that these warnings do not happen when
CONFIG_KASAN_STACK is disabled.

Link: https://github.com/ClangBuiltLinux/linux/issues/1453
References: 6baec880 ("kasan: turn off asan-stack for clang-8 and earlier")
Link: https://lkml.kernel.org/r/20210922205525.570068-1-nathan@kernel.orgSigned-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If X2TLB=y (CPU_SHX2=y or CPU_SHX3=y, e.g. migor_defconfig), pgd_t.pgd
is "unsigned long long", causing:

    In file included from arch/sh/include/asm/pgtable.h:13,
		     from include/linux/pgtable.h:6,
		     from include/linux/mm.h:33,
		     from arch/sh/kernel/asm-offsets.c:14:
    arch/sh/include/asm/pgtable-3level.h: In function `pud_pgtable':
    arch/sh/include/asm/pgtable-3level.h:37:9: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
       37 |  return (pmd_t *)pud_val(pud);
	  |         ^

Fix this by adding an intermediate cast to "unsigned long", which is
basically what the old code did before.

Link: https://lkml.kernel.org/r/2c2eef3c9a2f57e5609100a4864715ccf253d30f.1631713483.git.geert+renesas@glider.be
Fixes: 9cf6fa24 ("mm: rename pud_page_vaddr to pud_pgtable and make it return pmd_t *")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Daniel Palmer <daniel@thingy.jp>
Acked-by: Rob Landley <rob@landley.net>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Cc: Rich Felker <dalias@libc.org>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Sync up MR_DEMOTION to migrate_reason_names and add a synch prompt.

Link: https://lkml.kernel.org/r/20210921064553.293905-3-o451686892@gmail.com
Fixes: 26aa2d19 ("mm/migrate: demote pages during reclaim")
Signed-off-by: Weizhao Ouyang <o451686892@gmail.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Sync up MR_CONTIG_RANGE and MR_LONGTERM_PIN to migrate_reason_names.

Link: https://lkml.kernel.org/r/20210921064553.293905-2-o451686892@gmail.com
Fixes: 31025351 ("mm/migrate: rename migration reason MR_CMA to MR_CONTIG_RANGE")
Fixes: d1e153fe ("mm/gup: migrate pinned pages out of movable zone")
Signed-off-by: Weizhao Ouyang <o451686892@gmail.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Yang Shi <yang.shi@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Mina Almasry <almasrymina@google.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Wei Xu <weixugc@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The kernel test robot reported the regression of fio.write_iops[1] with
commit 8cc621d2 ("mm: fs: invalidate BH LRU during page migration").

Since lru_add_drain is called frequently, invalidate bh_lrus there could
increase bh_lrus cache miss ratio, which needs more IO in the end.

This patch moves the bh_lrus invalidation from the hot path( e.g.,
zap_page_range, pagevec_release) to cold path(i.e., lru_add_drain_all,
lru_cache_disable).

Zhengjun Xing confirmed
 "I test the patch, the regression reduced to -2.9%"

[1] https://lore.kernel.org/lkml/20210520083144.GD14190@xsang-OptiPlex-9020/
[2] 8cc621d2, mm: fs: invalidate BH LRU during page migration

Link: https://lkml.kernel.org/r/20210907212347.1977686-1-minchan@kernel.orgSigned-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: kernel test robot <oliver.sang@intel.com>
Reviewed-by: Chris Goldsworthy <cgoldswo@codeaurora.org>
Tested-by: "Xing, Zhengjun" <zhengjun.xing@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Building Linux for ppc64le with Ubuntu clang version
12.0.0-3ubuntu1~21.04.1 shows the warning below.

    arch/powerpc/boot/inffast.c:20:1: warning: unused function 'get_unaligned16' [-Wunused-function]
    get_unaligned16(const unsigned short *p)
    ^
    1 warning generated.

Fix it by moving the check from the preprocessor to C, so the compiler
sees the use.

Link: https://lkml.kernel.org/r/20210920084332.5752-1-pmenzel@molgen.mpg.deSigned-off-by: Paul Menzel <pmenzel@molgen.mpg.de>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>