When calling debugfs functions, there is no need to ever check the
return value. The function can work or not, but the code logic should
never do something different based on this.

The only way this can fail is if:

 * debugfs superblock can not be pinned - something really went wrong with the
 vfs layer.
 * file is created with same name - the caller's fault.
 * new_inode() fails - happens if memory is exhausted.

so failing to clean up debugfs properly is the least of the system's
sproblems in uch a situation.

 [ bp: Extend commit message, remove unused err var in inject_init(). ]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190612151531.GA16278@kroah.com

The OS is expected to write all bits to MCA_CTL for each bank,
thus enabling error reporting in all banks. However, some banks
may be unused in which case the registers for such banks are
Read-as-Zero/Writes-Ignored. Also, the OS may avoid setting some control
bits because of quirks, etc.

A bank can be considered uninitialized if the MCA_CTL register returns
zero. This is because either the OS did not write anything or because
the hardware is enforcing RAZ/WI for the bank.

Set a bank's init value based on if the control bits are set or not in
hardware. Return an error code in the sysfs interface for uninitialized
banks.

Do a final bank init check in a separate function which is not part of
any user-controlled code flows. This is so a user may enable/disable a
bank during runtime without having to restart their system.

 [ bp: Massage a bit. Discover bank init state at boot. ]
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "x86@kernel.org" <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190607201752.221446-6-Yazen.Ghannam@amd.com

The number of MCA banks is provided per logical CPU. Historically, this
number has been the same across all CPUs, but this is not an
architectural guarantee. Future AMD systems may have MCA bank counts
that vary between logical CPUs in a system.

This issue was partially addressed in

  006c0770 ("x86/mce: Handle varying MCA bank counts")

by allocating structures using the maximum number of MCA banks and by
saving the maximum MCA bank count in a system as the global count. This
means that some extra structures are allocated. Also, this means that
CPUs will spend more time in the #MC and other handlers checking extra
MCA banks.

Thus, define the number of MCA banks as a per-CPU variable.

 [ bp: Make mce_num_banks an unsigned int. ]
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "x86@kernel.org" <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190607201752.221446-5-Yazen.Ghannam@amd.com

On legacy systems, the addresses of the MCA_MISC* registers need to be
recursively discovered based on a Block Pointer field in the registers.

On Scalable MCA systems, the register space is fixed, and particular
addresses can be derived by regular offsets for bank and register type.
This fixed address space includes the MCA_MISC* registers.

MCA_MISC0 is always available for each MCA bank. MCA_MISC1 through
MCA_MISC4 are considered available if MCA_MISC0[BlkPtr]=1.

Cache the value of MCA_MISC0[BlkPtr] for each bank and per CPU. This
needs to be done only during init. The values should be saved per CPU
to accommodate heterogeneous SMCA systems.

Redo smca_get_block_address() to directly return the block addresses.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "x86@kernel.org" <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190607201752.221446-4-Yazen.Ghannam@amd.com

Current AMD systems have unique MCA banks per logical CPU even though
the type of the banks may all align to the same bank number. Each CPU
will have control of a set of MCA banks in the hardware and these are
not shared with other CPUs.

For example, bank 0 may be the Load-Store Unit on every logical CPU, but
each bank 0 is a unique structure in the hardware. In other words, there
isn't a *single* Load-Store Unit at MCA bank 0 that all logical CPUs
share.

This idea extends even to non-core MCA banks. For example, CPU0 and CPU4
may see a Unified Memory Controller at bank 15, but each CPU is actually
seeing a unique hardware structure that is not shared with other CPUs.

Because the MCA banks are all unique hardware structures, it would be
good to control them in a more granular way. For example, if there is a
known issue with the Floating Point Unit on CPU5 and a user wishes to
disable an error type on the Floating Point Unit, then it would be good
to do this only for CPU5 rather than all CPUs.

Also, future AMD systems may have heterogeneous MCA banks. Meaning
the bank numbers may not necessarily represent the same types between
CPUs. For example, bank 20 visible to CPU0 may be a Unified Memory
Controller and bank 20 visible to CPU4 may be a Coherent Slave. So
granular control will be even more necessary should the user wish to
control specific MCA banks.

Split the device attributes from struct mce_bank leaving only the MCA
bank control fields.

Make struct mce_banks[] per_cpu in order to have more granular control
over individual MCA banks in the hardware.

Allocate the device attributes statically based on the maximum number of
MCA banks supported. The sysfs interface will use as many as needed per
CPU. Currently, this is set to mca_cfg.banks, but will be changed to a
per_cpu bank count in a future patch.

Allocate the MCA control bits statically. This is in order to avoid
locking warnings when memory is allocated during secondary CPUs' init
sequences.

Also, remove the now unnecessary return values from
__mcheck_cpu_mce_banks_init() and __mcheck_cpu_cap_init().

Redo the sysfs store/show functions to handle the per_cpu mce_banks[].

 [ bp: s/mce_banks_percpu/mce_banks_array/g ]

[ Locking issue reported by ]
Reported-by: kernel test robot <rong.a.chen@intel.com>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "linux-edac@vger.kernel.org" <linux-edac@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "x86@kernel.org" <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190607201752.221446-3-Yazen.Ghannam@amd.com

The struct mce_banks[] array is only used in mce/core.c so move its
definition there and make it static. Also, change the "init" field to
bool type.
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: "x86@kernel.org" <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190607201752.221446-2-Yazen.Ghannam@amd.com

Signed-off-by: Borislav Petkov <bp@suse.de>

The pfn and array files in (debugfs)/ras/cec are intended for debugging
the CEC code itself. They are not needed on production systems, so the
default setting for this CONFIG option is "n".

 [ bp: Have it with less ifdeffery by using IS_ENABLED(). ]
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>

When dumping the array elements, print them in the following format:

  [ PFN | generation in binary | count ]

to be perfectly clear what all those sections are.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>

... which is the better, more-fitting name anyway.

Tony:
 - make action_threshold u64 due to debugfs accessors expecting u64.
 - rename the remaining: s/count_threshold/action_threshold/g
Co-developed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: linux-edac <linux-edac@vger.kernel.org>

Check the elements order in the array after every insertion.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>

Free the array page if a failure is encountered while creating the
debugfs nodes.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>

When the value requested doesn't match the allowed (min,max) range,
the @data buffer should not be modified with the invalid value because
reading "decay_interval" shows it otherwise as if the previous write
succeeded.

Move the data write after the check.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>

The count_threshold should be checked unconditionally, after insertion
too, so that a count_threshold value of 1 can cause an immediate
offlining. I.e., offline the page on the *first* error encountered.

Add comments to make it clear what cec_add_elem() does, while at it.
Reported-by: WANG Chao <chao.wang@ucloud.cn>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac@vger.kernel.org
Link: https://lkml.kernel.org/r/20190418034115.75954-3-chao.wang@ucloud.cn

When inserting random PFNs for debugging the CEC through
(debugfs)/ras/cec/pfn, depending on the return value of pfn_set(),
multiple values get inserted per a single write.

That is because simple_attr_write() interprets a retval of 0 as
success and claims the whole input. However, pfn_set() returns the
cec_add_elem() value, which, if > 0 and smaller than the whole input
length, makes glibc continue issuing the write syscall until there's
input left:

  pfn_set
  simple_attr_write
  debugfs_attr_write
  full_proxy_write
  vfs_write
  ksys_write
  do_syscall_64
  entry_SYSCALL_64_after_hwframe

leading to those repeated calls.

Return 0 to fix that.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>

cec_timer_fn() is a timer callback which reads ce_arr.array[] and
updates its decay values. However, it runs in interrupt context and the
mutex protection the CEC uses for that array, is inadequate. Convert the
used timer to a workqueue to keep the tasks the CEC performs preemptible
and thus low-prio.

 [ bp: Rewrite commit message.
   s/timer/decay/gi to make it agnostic as to what facility is used. ]

Fixes: 011d8261 ("RAS: Add a Corrected Errors Collector")
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/20190416213351.28999-2-xiyou.wangcong@gmail.com

Switch to using Donald Knuth's binary search algorithm (The Art of
Computer Programming, vol. 3, section 6.2.1). This should've been done
from the very beginning but the author must've been smoking something
very potent at the time.

The problem with the current one was that it would return the wrong
element index in certain situations:

  https://lkml.kernel.org/r/CAM_iQpVd02zkVJ846cj-Fg1yUNuz6tY5q1Vpj4LrXmE06dPYYg@mail.gmail.com

and the noodling code after the loop was fishy at best.

So switch to using Knuth's binary search. The final result is much
cleaner and straightforward.

Fixes: 011d8261 ("RAS: Add a Corrected Errors Collector")
Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: linux-edac <linux-edac@vger.kernel.org>
Cc: <stable@vger.kernel.org>

Pull x86 fixes from Ingo Molnar:
 "Two fixes: a quirk for KVM guests running on certain AMD CPUs, and a
  KASAN related build fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/CPU/AMD: Don't force the CPB cap when running under a hypervisor
  x86/boot: Provide KASAN compatible aliases for string routines

Pull perf fixes from Ingo Molnar:
 "On the kernel side there's a bunch of ring-buffer ordering fixes for a
  reproducible bug, plus a PEBS constraints regression fix.

  Plus tooling fixes"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tools headers UAPI: Sync kvm.h headers with the kernel sources
  perf record: Fix s390 missing module symbol and warning for non-root users
  perf machine: Read also the end of the kernel
  perf test vmlinux-kallsyms: Ignore aliases to _etext when searching on kallsyms
  perf session: Add missing swap ops for namespace events
  perf namespace: Protect reading thread's namespace
  tools headers UAPI: Sync drm/drm.h with the kernel
  tools headers UAPI: Sync drm/i915_drm.h with the kernel
  tools headers UAPI: Sync linux/fs.h with the kernel
  tools headers UAPI: Sync linux/sched.h with the kernel
  tools arch x86: Sync asm/cpufeatures.h with the with the kernel
  tools include UAPI: Update copy of files related to new fspick, fsmount, fsconfig, fsopen, move_mount and open_tree syscalls
  perf arm64: Fix mksyscalltbl when system kernel headers are ahead of the kernel
  perf data: Fix 'strncat may truncate' build failure with recent gcc
  perf/ring-buffer: Use regular variables for nesting
  perf/ring-buffer: Always use {READ,WRITE}_ONCE() for rb->user_page data
  perf/ring_buffer: Add ordering to rb->nest increment
  perf/ring_buffer: Fix exposing a temporarily decreased data_head
  perf/x86/intel/ds: Fix EVENT vs. UEVENT PEBS constraints

Pull EFI fixes from Ingo Molnar:
 "Two EFI fixes: a quirk for weird systabs, plus add more robust error
  handling in the old 1:1 mapping code"

* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: Allow the number of EFI configuration tables entries to be zero
  efi/x86/Add missing error handling to old_memmap 1:1 mapping code

Pull stacktrace fix from Ingo Molnar:
 "Fix a stack_trace_save_tsk_reliable() regression"

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  stacktrace: Unbreak stack_trace_save_tsk_reliable()

Pull SPDX fixes from Greg KH:
 "Here are just two small patches, that fix up some found SPDX
  identifier issues.

  The first patch fixes an error in a previous SPDX fixup patch, that
  causes build errors when doing 'make clean' on the tree (the fact that
  almost no one noticed it reflects the fact that kernel developers
  don't like doing that option very often...)

  The second patch fixes up a number of places in the tree where people
  mistyped the string "SPDX-License-Identifier". Given that people can
  not even type their own name all the time without mistakes, this was
  bound to happen, and odds are, we will have to add some type of check
  for this to checkpatch.pl to catch this happening in the future.

  Both of these have passed testing by 0-day"

* tag 'spdx-5.2-rc3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  treewide: fix typos of SPDX-License-Identifier
  crypto: ux500 - fix license comment syntax error

Pull powerpc fixes from Michael Ellerman:
 "A minor fix to our IMC PMU code to print a less confusing error
  message when the driver can't initialise properly.

  A fix for a bug where a user requesting an unsupported branch sampling
  filter can corrupt PMU state, preventing the PMU from counting
  properly.

  And finally a fix for a bug in our support for kexec_file_load(),
  which prevented loading a kernel and initramfs. Most versions of kexec
  don't yet use kexec_file_load().

  Thanks to: Anju T Sudhakar, Dave Young, Madhavan Srinivasan, Ravi
  Bangoria, Thiago Jung Bauermann"

* tag 'powerpc-5.2-3' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/kexec: Fix loading of kernel + initramfs with kexec_file_load()
  powerpc/perf: Fix MMCRA corruption by bhrb_filter
  powerpc/powernv: Return for invalid IMC domain

Pull KVM fixes from Paolo Bonzini:
 "Fixes for PPC and s390"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: PPC: Book3S HV: Restore SPRG3 in kvmhv_p9_guest_entry()
  KVM: PPC: Book3S HV: Fix lockdep warning when entering guest on POWER9
  KVM: PPC: Book3S HV: XIVE: Fix page offset when clearing ESB pages
  KVM: PPC: Book3S HV: XIVE: Take the srcu read lock when accessing memslots
  KVM: PPC: Book3S HV: XIVE: Do not clear IRQ data of passthrough interrupts
  KVM: PPC: Book3S HV: XIVE: Introduce a new mutex for the XIVE device
  KVM: PPC: Book3S HV: XIVE: Fix the enforced limit on the vCPU identifier
  KVM: PPC: Book3S HV: XIVE: Do not test the EQ flag validity when resetting
  KVM: PPC: Book3S HV: XIVE: Clear file mapping when device is released
  KVM: PPC: Book3S HV: Don't take kvm->lock around kvm_for_each_vcpu
  KVM: PPC: Book3S: Use new mutex to synchronize access to rtas token list
  KVM: PPC: Book3S HV: Use new mutex to synchronize MMU setup
  KVM: PPC: Book3S HV: Avoid touching arch.mmu_ready in XIVE release functions
  KVM: s390: Do not report unusabled IDs via KVM_CAP_MAX_VCPU_ID
  kvm: fix compile on s390 part 2

Pull i2c fixes from Wolfram Sang:
 "A memleak fix for the core, two driver bugfixes, as well as fixing
  missing file patterns to MAINTAINERS"

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  MAINTAINERS: add I2C DT bindings to ARM platforms
  MAINTAINERS: add DT bindings to i2c drivers
  i2c: synquacer: fix synquacer_i2c_doxfer() return value
  i2c: mlxcpld: Fix wrong initialization order in probe
  i2c: dev: fix potential memory leak in i2cdev_ioctl_rdwr

Pull thermal SoC fix from Eduardo Valentin:
 "A single revert, detected to cause issues on the tsens driver"

* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/evalenti/linux-soc-thermal:
  Revert "drivers: thermal: tsens: Add new operation to check if a sensor is enabled"

Merge tag 'led-fixes-for-5.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds

Pull LED fix from Jacek Anaszewski:
 "Fix for a recent change in LED core, that didn't take into account the
  possibility of calling led_blink_setup() from atomic context"

* tag 'led-fixes-for-5.2-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds:
  leds: avoid flush_work in atomic context

Pull block fixes from Jens Axboe:

 - A set of patches fixing code comments / kerneldoc (Bart)

 - Don't allow loop file change for exclusive open (Jan)

 - Fix revalidate of hidden genhd (Jan)

 - Init queue failure memory free fix (Jes)

 - Improve rq limits failure print (John)

 - Fixup for queue removal/addition (Ming)

 - Missed error progagation for io_uring buffer registration (Pavel)

* tag 'for-linus-20190601' of git://git.kernel.dk/linux-block:
  block: print offending values when cloned rq limits are exceeded
  blk-mq: Document the blk_mq_hw_queue_to_node() arguments
  blk-mq: Fix spelling in a source code comment
  block: Fix bsg_setup_queue() kernel-doc header
  block: Fix rq_qos_wait() kernel-doc header
  block: Fix blk_mq_*_map_queues() kernel-doc headers
  block: Fix throtl_pending_timer_fn() kernel-doc header
  block: Convert blk_invalidate_devt() header into a non-kernel-doc header
  block/partitions/ldm: Convert a kernel-doc header into a non-kernel-doc header
  blk-mq: Fix memory leak in error handling
  block: don't protect generic_make_request_checks with blk_queue_enter
  block: move blk_exit_queue into __blk_release_queue
  block: Don't revalidate bdev of hidden gendisk
  loop: Don't change loop device under exclusive opener
  io_uring: Fix __io_uring_register() false success

Pull SCSI fixes from James Bottomley:
 "Six minor fixes to device drivers and one to the multipath alua
  handler.

  The most extensive fix is the zfcp port remove prevention one, but
  it's impact is only s390"

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: libsas: delete sas port if expander discover failed
  scsi: libsas: only clear phy->in_shutdown after shutdown event done
  scsi: scsi_dh_alua: Fix possible null-ptr-deref
  scsi: smartpqi: properly set both the DMA mask and the coherent DMA mask
  scsi: zfcp: fix to prevent port_remove with pure auto scan LUNs (only sdevs)
  scsi: zfcp: fix missing zfcp_port reference put on -EBUSY from port_remove
  scsi: libcxgbi: add a check for NULL pointer in cxgbi_check_route()

Merge misc fixes from Andrew Morton:
 "Various fixes and followups"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm, compaction: make sure we isolate a valid PFN
  include/linux/generic-radix-tree.h: fix kerneldoc comment
  kernel/signal.c: trace_signal_deliver when signal_group_exit
  drivers/iommu/intel-iommu.c: fix variable 'iommu' set but not used
  spdxcheck.py: fix directory structures
  kasan: initialize tag to 0xff in __kasan_kmalloc
  z3fold: fix sheduling while atomic
  scripts/gdb: fix invocation when CONFIG_COMMON_CLK is not set
  mm/gup: continue VM_FAULT_RETRY processing even for pre-faults
  ocfs2: fix error path kobject memory leak
  memcg: make it work on sparse non-0-node systems
  mm, memcg: consider subtrees in memory.events
  prctl_set_mm: downgrade mmap_sem to read lock
  prctl_set_mm: refactor checks from validate_prctl_map
  kernel/fork.c: make max_threads symbol static
  arch/arm/boot/compressed/decompress.c: fix build error due to lz4 changes
  arch/parisc/configs/c8000_defconfig: remove obsoleted CONFIG_DEBUG_SLAB_LEAK
  mm/vmalloc.c: fix typo in comment
  lib/sort.c: fix kernel-doc notation warnings
  mm: fix Documentation/vm/hmm.rst Sphinx warnings

When we have holes in a normal memory zone, we could endup having
cached_migrate_pfns which may not necessarily be valid, under heavy memory
pressure with swapping enabled ( via __reset_isolation_suitable(),
triggered by kswapd).

Later if we fail to find a page via fast_isolate_freepages(), we may end
up using the migrate_pfn we started the search with, as valid page.  This
could lead to accessing NULL pointer derefernces like below, due to an
invalid mem_section pointer.

Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008 [47/1825]
 Mem abort info:
   ESR = 0x96000004
   Exception class = DABT (current EL), IL = 32 bits
   SET = 0, FnV = 0
   EA = 0, S1PTW = 0
 Data abort info:
   ISV = 0, ISS = 0x00000004
   CM = 0, WnR = 0
 user pgtable: 4k pages, 48-bit VAs, pgdp = 0000000082f94ae9
 [0000000000000008] pgd=0000000000000000
 Internal error: Oops: 96000004 [#1] SMP
 ...
 CPU: 10 PID: 6080 Comm: qemu-system-aar Not tainted 510-rc1+ #6
 Hardware name: AmpereComputing(R) OSPREY EV-883832-X3-0001/OSPREY, BIOS 4819 09/25/2018
 pstate: 60000005 (nZCv daif -PAN -UAO)
 pc : set_pfnblock_flags_mask+0x58/0xe8
 lr : compaction_alloc+0x300/0x950
 [...]
 Process qemu-system-aar (pid: 6080, stack limit = 0x0000000095070da5)
 Call trace:
  set_pfnblock_flags_mask+0x58/0xe8
  compaction_alloc+0x300/0x950
  migrate_pages+0x1a4/0xbb0
  compact_zone+0x750/0xde8
  compact_zone_order+0xd8/0x118
  try_to_compact_pages+0xb4/0x290
  __alloc_pages_direct_compact+0x84/0x1e0
  __alloc_pages_nodemask+0x5e0/0xe18
  alloc_pages_vma+0x1cc/0x210
  do_huge_pmd_anonymous_page+0x108/0x7c8
  __handle_mm_fault+0xdd4/0x1190
  handle_mm_fault+0x114/0x1c0
  __get_user_pages+0x198/0x3c0
  get_user_pages_unlocked+0xb4/0x1d8
  __gfn_to_pfn_memslot+0x12c/0x3b8
  gfn_to_pfn_prot+0x4c/0x60
  kvm_handle_guest_abort+0x4b0/0xcd8
  handle_exit+0x140/0x1b8
  kvm_arch_vcpu_ioctl_run+0x260/0x768
  kvm_vcpu_ioctl+0x490/0x898
  do_vfs_ioctl+0xc4/0x898
  ksys_ioctl+0x8c/0xa0
  __arm64_sys_ioctl+0x28/0x38
  el0_svc_common+0x74/0x118
  el0_svc_handler+0x38/0x78
  el0_svc+0x8/0xc
 Code: f8607840 f100001f 8b011401 9a801020 (f9400400)
 ---[ end trace af6a35219325a9b6 ]---

The issue was reported on an arm64 server with 128GB with holes in the
zone (e.g, [32GB@4GB, 96GB@544GB]), with a swap device enabled, while
running 100 KVM guest instances.

This patch fixes the issue by ensuring that the page belongs to a valid
PFN when we fallback to using the lower limit of the scan range upon
failure in fast_isolate_freepages().

Link: http://lkml.kernel.org/r/1558711908-15688-1-git-send-email-suzuki.poulose@arm.com
Fixes: 5a811889 ("mm, compaction: use free lists to quickly locate a migration target")
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Reported-by: Marc Zyngier <marc.zyngier@arm.com>
Reviewed-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Marc Zyngier <marc.zyngier@arm.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 DOC comment block section in include/linux/generic-radix-tree.h
contained a spurious colon, causing this warning in the documentation
build:

  include/linux/generic-radix-tree.h:1: warning: no structured comments found

Remove the colon and make the docs build happy.

Link: http://lkml.kernel.org/r/20190524141933.74ae9050@lwn.netSigned-off-by: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In the fixes commit, removing SIGKILL from each thread signal mask and
executing "goto fatal" directly will skip the call to
"trace_signal_deliver".  At this point, the delivery tracking of the
SIGKILL signal will be inaccurate.

Therefore, we need to add trace_signal_deliver before "goto fatal" after
executing sigdelset.

Note: SEND_SIG_NOINFO matches the fact that SIGKILL doesn't have any info.

Link: http://lkml.kernel.org/r/20190425025812.91424-1-weizhenliang@huawei.com
Fixes: cf43a757 ("signal: Restore the stop PTRACE_EVENT_EXIT")
Signed-off-by: Zhenliang Wei <weizhenliang@huawei.com>
Reviewed-by: Christian Brauner <christian@brauner.io>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Ivan Delalande <colona@arista.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit cf04eee8 ("iommu/vt-d: Include ACPI devices in iommu=pt")
added for_each_active_iommu() in iommu_prepare_static_identity_mapping()
but never used the each element, i.e, "drhd->iommu".

drivers/iommu/intel-iommu.c: In function
'iommu_prepare_static_identity_mapping':
drivers/iommu/intel-iommu.c:3037:22: warning: variable 'iommu' set but
not used [-Wunused-but-set-variable]
 struct intel_iommu *iommu;

Fixed the warning by appending a compiler attribute __maybe_unused for it.

Link: http://lkml.kernel.org/r/20190523013314.2732-1-cai@lca.pwSigned-off-by: Qian Cai <cai@lca.pw>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The LICENSE directory has recently changed structure and this makes
spdxcheck fails as per below:

FAIL: "Blob or Tree named 'other' not found"
Traceback (most recent call last):
  File "scripts/spdxcheck.py", line 240, in <module>
spdx = read_spdxdata(repo)
  File "scripts/spdxcheck.py", line 41, in read_spdxdata
for el in lictree[d].traverse():
[...]
KeyError: "Blob or Tree named 'other' not found"

Fix the script to restore the correctness on checkpatch License checking.

References: 62be257e ("LICENSES: Rename other to deprecated")
References: 8ea8814f ("LICENSES: Clearly mark dual license only licenses")
Link: http://lkml.kernel.org/r/20190523084755.56739-1-vincenzo.frascino@arm.comSigned-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Cc: Joe Perches <joe@perches.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeremy Cline <jcline@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When building with -Wuninitialized and CONFIG_KASAN_SW_TAGS unset, Clang
warns:

mm/kasan/common.c:484:40: warning: variable 'tag' is uninitialized when
used here [-Wuninitialized]
        kasan_unpoison_shadow(set_tag(object, tag), size);
                                              ^~~

set_tag ignores tag in this configuration but clang doesn't realize it at
this point in its pipeline, as it points to arch_kasan_set_tag as being
the point where it is used, which will later be expanded to (void
*)(object) without a use of tag.  Initialize tag to 0xff, as it removes
this warning and doesn't change the meaning of the code.

Link: https://github.com/ClangBuiltLinux/linux/issues/465
Link: http://lkml.kernel.org/r/20190502163057.6603-1-natechancellor@gmail.com
Fixes: 7f94ffbc ("kasan: add hooks implementation for tag-based mode")
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Nick Desaulniers <ndesaulniers@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>

kmem_cache_alloc() may be called from z3fold_alloc() in atomic context, so
we need to pass correct gfp flags to avoid "scheduling while atomic" bug.

Link: http://lkml.kernel.org/r/20190523153245.119dfeed55927e8755250ddd@gmail.com
Fixes: 7c2b8baa ("mm/z3fold.c: add structure for buddy handles")
Signed-off-by: Vitaly Wool <vitaly.vul@sony.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

CLK_GET_RATE_NOCACHE depends on CONFIG_COMMON_CLK.  Importing constants.py
when CONFIG_COMMON_CLK is not defined causes:

  (gdb) lx-symbols
  (...)
    File "scripts/gdb/linux/proc.py", line 15, in <module>
      from linux import constants
    File "scripts/gdb/linux/constants.py", line 2, in <module>
      LX_CLK_GET_RATE_NOCACHE = gdb.parse_and_eval("CLK_GET_RATE_NOCACHE")
  gdb.error: No symbol "CLK_GET_RATE_NOCACHE" in current context.

Link: http://lkml.kernel.org/r/20190523195313.24701-1-farosas@linux.ibm.com
Fixes: e7e6f462 ("scripts/gdb: print cached rate in lx-clk-summary")
Signed-off-by: Fabiano Rosas <farosas@linux.ibm.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Cc: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kieran Bingham <kbingham@kernel.org>
Cc: Leonard Crestez <leonard.crestez@nxp.com>
Cc: Jackie Liu <liuyun01@kylinos.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When get_user_pages*() is called with pages = NULL, the processing of
VM_FAULT_RETRY terminates early without actually retrying to fault-in all
the pages.

If the pages in the requested range belong to a VMA that has userfaultfd
registered, handle_userfault() returns VM_FAULT_RETRY *after* user space
has populated the page, but for the gup pre-fault case there's no actual
retry and the caller will get no pages although they are present.

This issue was uncovered when running post-copy memory restore in CRIU
after d9c9ce34 ("x86/fpu: Fault-in user stack if
copy_fpstate_to_sigframe() fails").

After this change, the copying of FPU state to the sigframe switched from
copy_to_user() variants which caused a real page fault to get_user_pages()
with pages parameter set to NULL.

In post-copy mode of CRIU, the destination memory is managed with
userfaultfd and lack of the retry for pre-fault case in get_user_pages()
causes a crash of the restored process.

Making the pre-fault behavior of get_user_pages() the same as the "normal"
one fixes the issue.

Link: http://lkml.kernel.org/r/1557844195-18882-1-git-send-email-rppt@linux.ibm.com
Fixes: d9c9ce34 ("x86/fpu: Fault-in user stack if copy_fpstate_to_sigframe() fails")
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Tested-by: Andrei Vagin <avagin@gmail.com> [https://travis-ci.org/avagin/linux/builds/533184940]
Tested-by: Hugh Dickins <hughd@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>