Pull perf tooling fixes from Thomas Gleixner:
 "A set of updates for perf tools and documentation:

  perf header:
    - Prevent a division by zero
    - Deal with an uninitialized warning proper

  libbpf:
    - Fix the missiong __WORDSIZE definition for musl & al

  UAPI headers:
    - Synchronize kernel headers

  Documentation:
    - Fix the memory units for perf.data size"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  libbpf: fix missing __WORDSIZE definition
  perf tools: Fix perf.data documentation units for memory size
  perf header: Fix use of unitialized value warning
  perf header: Fix divide by zero error if f_header.attr_size==0
  tools headers UAPI: Sync if_link.h with the kernel
  tools headers UAPI: Sync sched.h with the kernel
  tools headers UAPI: Sync usbdevice_fs.h with the kernels to get new ioctl
  tools perf beauty: Fix usbdevfs_ioctl table generator to handle _IOC()
  tools headers UAPI: Update tools's copy of drm.h headers
  tools headers UAPI: Update tools's copy of mman.h headers
  tools headers UAPI: Update tools's copy of kvm.h headers
  tools include UAPI: Sync x86's syscalls_64.tbl and generic unistd.h to pick up clone3 and pidfd_open

Pull vdso timer fixes from Thomas Gleixner:
 "A series of commits to deal with the regression caused by the generic
  VDSO implementation.

  The usage of clock_gettime64() for 32bit compat fallback syscalls
  caused seccomp filters to kill innocent processes because they only
  allow clock_gettime().

  Handle the compat syscalls with clock_gettime() as before, which is
  not a functional problem for the VDSO as the legacy compat application
  interface is not y2038 safe anyway. It's just extra fallback code
  which needs to be implemented on every architecture.

  It's opt in for now so that it does not break the compile of already
  converted architectures in linux-next. Once these are fixed, the
  #ifdeffery goes away.

  So much for trying to be smart and reuse code..."

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  arm64: compat: vdso: Use legacy syscalls as fallback
  x86/vdso/32: Use 32bit syscall fallback
  lib/vdso/32: Provide legacy syscall fallbacks
  lib/vdso: Move fallback invocation to the callers
  lib/vdso/32: Remove inconsistent NULL pointer checks

Pull irq fixes from Thomas Gleixner:
 "A small bunch of fixes from the irqchip department:

   - Fix a couple of UAF on error paths (RZA1, GICv3 ITS)

   - Fix iMX GPCv2 trigger setting

   - Add missing of_node_put() on error path in MBIGEN

   - Add another bunch of /* fall-through */ to silence warnings"

* 'irq-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  irqchip/renesas-rza1: Fix an use-after-free in rza1_irqc_probe()
  irqchip/irq-imx-gpcv2: Forward irq type to parent
  irqchip/irq-mbigen: Add of_node_put() before return
  irqchip/gic-v3-its: Free unused vpt_page when alloc vpe table fail
  irqchip/gic-v3: Mark expected switch fall-through

Pull xfs fixes from Darrick Wong:

 - Avoid leaking kernel stack contents to userspace

 - Fix a potential null pointer dereference in the dabtree scrub code

* tag 'xfs-5.3-fixes-1' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: Fix possible null-pointer dereferences in xchk_da_btree_block_check_sibling()
  xfs: fix stack contents leakage in the v1 inumber ioctls

Merge misc fixes from Andrew Morton:
 "17 fixes"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  drivers/acpi/scan.c: document why we don't need the device_hotplug_lock
  memremap: move from kernel/ to mm/
  lib/test_meminit.c: use GFP_ATOMIC in RCU critical section
  asm-generic: fix -Wtype-limits compiler warnings
  cgroup: kselftest: relax fs_spec checks
  mm/memory_hotplug.c: remove unneeded return for void function
  mm/migrate.c: initialize pud_entry in migrate_vma()
  coredump: split pipe command whitespace before expanding template
  page flags: prioritize kasan bits over last-cpuid
  ubsan: build ubsan.c more conservatively
  kasan: remove clang version check for KASAN_STACK
  mm: compaction: avoid 100% CPU usage during compaction when a task is killed
  mm: migrate: fix reference check race between __find_get_block() and migration
  mm: vmscan: check if mem cgroup is disabled or not before calling memcg slab shrinker
  ocfs2: remove set but not used variable 'last_hash'
  Revert "kmemleak: allow to coexist with fault injection"
  kernel/signal.c: fix a kernel-doc markup

Pull RISC-V fixes from Paul Walmsley:
 "Three minor RISC-V-related changes for v5.3-rc3:

   - Add build ID to VDSO builds to avoid a double-free in perf when
     libelf isn't used

   - Align the RV64 defconfig to the output of "make savedefconfig" so
     subsequent defconfig patches don't get out of hand

   - Drop a superfluous DT property from the FU540 SoC DT data (since it
     must be already set in board data that includes it)"

* tag 'riscv/for-v5.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: defconfig: align RV64 defconfig to the output of "make savedefconfig"
  riscv: dts: fu540-c000: drop "timebase-frequency"
  riscv: Fix perf record without libelf support

Let's document why the lock is not needed in acpi_scan_init(), right now
this is not really obvious.

[akpm@linux-foundation.org: fix tpyo]
Link: http://lkml.kernel.org/r/20190731135306.31524-1-david@redhat.com


Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

memremap.c implements MM functionality for ZONE_DEVICE, so it really
should be in the mm/ directory, not the kernel/ one.

Link: http://lkml.kernel.org/r/20190722094143.18387-1-hch@lst.de


Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kmalloc() shouldn't sleep while in RCU critical section, therefore use
GFP_ATOMIC instead of GFP_KERNEL.

The bug was spotted by the 0day kernel testing robot.

Link: http://lkml.kernel.org/r/20190725121703.210874-1-glider@google.com


Fixes: 7e659650cbda ("lib: introduce test_meminit module")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Commit d66acc39 ("bitops: Optimise get_order()") introduced a
compilation warning because "rx_frag_size" is an "ushort" while
PAGE_SHIFT here is 16.

The commit changed the get_order() to be a multi-line macro where
compilers insist to check all statements in the macro even when
__builtin_constant_p(rx_frag_size) will return false as "rx_frag_size"
is a module parameter.

In file included from ./arch/powerpc/include/asm/page_64.h:107,
                 from ./arch/powerpc/include/asm/page.h:242,
                 from ./arch/powerpc/include/asm/mmu.h:132,
                 from ./arch/powerpc/include/asm/lppaca.h:47,
                 from ./arch/powerpc/include/asm/paca.h:17,
                 from ./arch/powerpc/include/asm/current.h:13,
                 from ./include/linux/thread_info.h:21,
                 from ./arch/powerpc/include/asm/processor.h:39,
                 from ./include/linux/prefetch.h:15,
                 from drivers/net/ethernet/emulex/benet/be_main.c:14:
drivers/net/ethernet/emulex/benet/be_main.c: In function 'be_rx_cqs_create':
./include/asm-generic/getorder.h:54:9: warning: comparison is always
true due to limited range of data type [-Wtype-limits]
   (((n) < (1UL << PAGE_SHIFT)) ? 0 :  \
         ^
drivers/net/ethernet/emulex/benet/be_main.c:3138:33: note: in expansion
of macro 'get_order'
  adapter->big_page_size = (1 << get_order(rx_frag_size)) * PAGE_SIZE;
                                 ^~~~~~~~~

Fix it by moving all of this multi-line macro into a proper function,
and killing __get_order() off.

[akpm@linux-foundation.org: remove __get_order() altogether]
[cai@lca.pw: v2]
  Link: http://lkml.kernel.org/r/1564000166-31428-1-git-send-email-cai@lca.pw
Link: http://lkml.kernel.org/r/1563914986-26502-1-git-send-email-cai@lca.pw
Fixes: d66acc39

 ("bitops: Optimise get_order()")
Signed-off-by: Qian Cai <cai@lca.pw>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Howells <dhowells@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Bill Wendling <morbo@google.com>
Cc: James Y Knight <jyknight@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

On my laptop most memcg kselftests were being skipped because it claimed
cgroup v2 hierarchy wasn't mounted, but this isn't correct.  Instead, it
seems current systemd HEAD mounts it with the name "cgroup2" instead of
"cgroup":

    % grep cgroup /proc/mounts
    cgroup2 /sys/fs/cgroup cgroup2 rw,nosuid,nodev,noexec,relatime,nsdelegate 0 0

I can't think of a reason to need to check fs_spec explicitly
since it's arbitrary, so we can just rely on fs_vfstype.

After these changes, `make TARGETS=cgroup kselftest` actually runs the
cgroup v2 tests in more cases.

Link: http://lkml.kernel.org/r/20190723210737.GA487@chrisdown.name


Signed-off-by: Chris Down <chris@chrisdown.name>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

return is unneeded in void function

Link: http://lkml.kernel.org/r/20190723130814.21826-1-houweitaoo@gmail.com


Signed-off-by: Weitao Hou <houweitaoo@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls
migrate_vma_collect() which initializes a struct mm_walk but didn't
initialize mm_walk.pud_entry.  (Found by code inspection) Use a C
structure initialization to make sure it is set to NULL.

Link: http://lkml.kernel.org/r/20190719233225.12243-1-rcampbell@nvidia.com
Fixes: 8763cb45

 ("mm/migrate: new memory migration helper for use with device memory")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Save the offsets of the start of each argument to avoid having to update
pointers to each argument after every corename krealloc and to avoid
having to duplicate the memory for the dump command.

Executable names containing spaces were previously being expanded from
%e or %E and then split in the middle of the filename.  This is
incorrect behaviour since an argument list can represent arguments with
spaces.

The splitting could lead to extra arguments being passed to the core
dump handler that it might have interpreted as options or ignored
completely.

Core dump handlers that are not aware of this Linux kernel issue will be
using %e or %E without considering that it may be split and so they will
be vulnerable to processes with spaces in their names breaking their
argument list.  If their internals are otherwise well written, such as
if they are written in shell but quote arguments, they will work better
after this change than before.  If they are not well written, then there
is a slight chance of breakage depending on the details of the code but
they will already be fairly broken by the split filenames.

Core dump handlers that are aware of this Linux kernel issue will be
placing %e or %E as the last item in their core_pattern and then
aggregating all of the remaining arguments into one, separated by
spaces.  Alternatively they will be obtaining the filename via other
methods.  Both of these will be compatible with the new arrangement.

A side effect from this change is that unknown template types (for
example %z) result in an empty argument to the dump handler instead of
the argument being dropped.  This is a desired change as:

It is easier for dump handlers to process empty arguments than dropped
ones, especially if they are written in shell or don't pass each
template item with a preceding command-line option in order to
differentiate between individual template types.  Most core_patterns in
the wild do not use options so they can confuse different template types
(especially numeric ones) if an earlier one gets dropped in old kernels.
If the kernel introduces a new template type and a core_pattern uses it,
the core dump handler might not expect that the argument can be dropped
in old kernels.

For example, this can result in security issues when %d is dropped in
old kernels.  This happened with the corekeeper package in Debian and
resulted in the interface between corekeeper and Linux having to be
rewritten to use command-line options to differentiate between template
types.

The core_pattern for most core dump handlers is written by the handler
author who would generally not insert unknown template types so this
change should be compatible with all the core dump handlers that exist.

Link: http://lkml.kernel.org/r/20190528051142.24939-1-pabs3@bonedaddy.net
Fixes: 74aadce9

 ("core_pattern: allow passing of arguments to user mode helper when core_pattern is a pipe")
Signed-off-by: Paul Wise <pabs3@bonedaddy.net>
Reported-by: Jakub Wilk <jwilk@jwilk.net> [https://bugs.debian.org/924398]
Reported-by: Paul Wise <pabs3@bonedaddy.net> [https://lore.kernel.org/linux-fsdevel/c8b7ecb8508895bf4adb62a748e2ea2c71854597.camel@bonedaddy.net/

]
Suggested-by: Jakub Wilk <jwilk@jwilk.net>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

ARM64 randdconfig builds regularly run into a build error, especially
when NUMA_BALANCING and SPARSEMEM are enabled but not SPARSEMEM_VMEMMAP:

  #error "KASAN: not enough bits in page flags for tag"

The last-cpuid bits are already contitional on the available space, so
the result of the calculation is a bit random on whether they were
already left out or not.

Adding the kasan tag bits before last-cpuid makes it much more likely to
end up with a successful build here, and should be reliable for
randconfig at least, as long as that does not randomize NR_CPUS or
NODES_SHIFT but uses the defaults.

In order for the modified check to not trigger in the x86 vdso32 code
where all constants are wrong (building with -m32), enclose all the
definitions with an #ifdef.

[arnd@arndb.de: build fix]
  Link: http://lkml.kernel.org/r/CAK8P3a3Mno1SWTcuAOT0Wa9VS15pdU6EfnkxLbDpyS55yO04+g@mail.gmail.com
Link: http://lkml.kernel.org/r/20190722115520.3743282-1-arnd@arndb.de
Link: https://lore.kernel.org/lkml/20190618095347.3850490-1-arnd@arndb.de/
Fixes: 2813b9c0

 ("kasan, mm, arm64: tag non slab memory allocated via pagealloc")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

objtool points out several conditions that it does not like, depending
on the combination with other configuration options and compiler
variants:

stack protector:
  lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0xbf: call to __stack_chk_fail() with UACCESS enabled
  lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0xbe: call to __stack_chk_fail() with UACCESS enabled

stackleak plugin:
  lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x4a: call to stackleak_track_stack() with UACCESS enabled
  lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x4a: call to stackleak_track_stack() with UACCESS enabled

kasan:
  lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch()+0x25: call to memcpy() with UACCESS enabled
  lib/ubsan.o: warning: objtool: __ubsan_handle_type_mismatch_v1()+0x25: call to memcpy() with UACCESS enabled

The stackleak and kasan options just need to be disabled for this file
as we do for other files already.  For the stack protector, we already
attempt to disable it, but this fails on clang because the check is
mixed with the gcc specific -fno-conserve-stack option.  According to
Andrey Ryabinin, that option is not even needed, dropping it here fixes
the stackprotector issue.

Link: http://lkml.kernel.org/r/20190722125139.1335385-1-arnd@arndb.de
Link: https://lore.kernel.org/lkml/20190617123109.667090-1-arnd@arndb.de/t/
Link: https://lore.kernel.org/lkml/20190722091050.2188664-1-arnd@arndb.de/t/
Fixes: d08965a2

 ("x86/uaccess, ubsan: Fix UBSAN vs. SMAP")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

asan-stack mode still uses dangerously large kernel stacks of tens of
kilobytes in some drivers, and it does not seem that anyone is working
on the clang bug.

Turn it off for all clang versions to prevent users from accidentally
enabling it once they update to clang-9, and to help automated build
testing with clang-9.

Link: https://bugs.llvm.org/show_bug.cgi?id=38809
Link: http://lkml.kernel.org/r/20190719200347.2596375-1-arnd@arndb.de
Fixes: 6baec880

 ("kasan: turn off asan-stack for clang-8 and earlier")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Reviewed-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

"howaboutsynergy" reported via kernel buzilla number 204165 that
compact_zone_order was consuming 100% CPU during a stress test for
prolonged periods of time.  Specifically the following command, which
should exit in 10 seconds, was taking an excessive time to finish while
the CPU was pegged at 100%.

  stress -m 220 --vm-bytes 1000000000 --timeout 10

Tracing indicated a pattern as follows

          stress-3923  [007]   519.106208: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106212: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106216: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106219: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106223: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106227: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106231: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106235: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106238: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0
          stress-3923  [007]   519.106242: mm_compaction_isolate_migratepages: range=(0x70bb80 ~ 0x70bb80) nr_scanned=0 nr_taken=0

Note that compaction is entered in rapid succession while scanning and
isolating nothing.  The problem is that when a task that is compacting
receives a fatal signal, it retries indefinitely instead of exiting
while making no progress as a fatal signal is pending.

It's not easy to trigger this condition although enabling zswap helps on
the basis that the timing is altered.  A very small window has to be hit
for the problem to occur (signal delivered while compacting and
isolating a PFN for migration that is not aligned to SWAP_CLUSTER_MAX).

This was reproduced locally -- 16G single socket system, 8G swap, 30%
zswap configured, vm-bytes 22000000000 using Colin Kings stress-ng
implementation from github running in a loop until the problem hits).
Tracing recorded the problem occurring almost 200K times in a short
window.  With this patch, the problem hit 4 times but the task existed
normally instead of consuming CPU.

This problem has existed for some time but it was made worse by commit
cf66f070 ("mm, compaction: do not consider a need to reschedule as
contention").  Before that commit, if the same condition was hit then
locks would be quickly contended and compaction would exit that way.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204165
Link: http://lkml.kernel.org/r/20190718085708.GE24383@techsingularity.net
Fixes: cf66f070

 ("mm, compaction: do not consider a need to reschedule as contention")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>	[5.1+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

buffer_migrate_page_norefs() can race with bh users in the following
way:

CPU1                                    CPU2
buffer_migrate_page_norefs()
  buffer_migrate_lock_buffers()
  checks bh refs
  spin_unlock(&mapping->private_lock)
                                        __find_get_block()
                                          spin_lock(&mapping->private_lock)
                                          grab bh ref
                                          spin_unlock(&mapping->private_lock)
  move page                               do bh work

This can result in various issues like lost updates to buffers (i.e.
metadata corruption) or use after free issues for the old page.

This patch closes the race by holding mapping->private_lock while the
mapping is being moved to a new page.  Ordinarily, a reference can be
taken outside of the private_lock using the per-cpu BH LRU but the
references are checked and the LRU invalidated if necessary.  The
private_lock is held once the references are known so the buffer lookup
slow path will spin on the private_lock.  Between the page lock and
private_lock, it should be impossible for other references to be
acquired and updates to happen during the migration.

A user had reported data corruption issues on a distribution kernel with
a similar page migration implementation as mainline.  The data
corruption could not be reproduced with this patch applied.  A small
number of migration-intensive tests were run and no performance problems
were noted.

[mgorman@techsingularity.net: Changelog, removed tracing]
Link: http://lkml.kernel.org/r/20190718090238.GF24383@techsingularity.net
Fixes: 89cb0888

 "mm: migrate: provide buffer_migrate_page_norefs()"
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>	[5.0+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Shakeel Butt reported premature oom on kernel with
"cgroup_disable=memory" since mem_cgroup_is_root() returns false even
though memcg is actually NULL.  The drop_caches is also broken.

It is because commit aeed1d32 ("mm/vmscan.c: generalize
shrink_slab() calls in shrink_node()") removed the !memcg check before
!mem_cgroup_is_root().  And, surprisingly root memcg is allocated even
though memory cgroup is disabled by kernel boot parameter.

Add mem_cgroup_disabled() check to make reclaimer work as expected.

Link: http://lkml.kernel.org/r/1563385526-20805-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: aeed1d32

 ("mm/vmscan.c: generalize shrink_slab() calls in shrink_node()")
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Reported-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Reviewed-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jan Hadrava <had@kam.mff.cuni.cz>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Qian Cai <cai@lca.pw>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: <stable@vger.kernel.org>	[4.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Fixes gcc '-Wunused-but-set-variable' warning:

  fs/ocfs2/xattr.c: In function ocfs2_xattr_bucket_find:
  fs/ocfs2/xattr.c:3828:6: warning: variable last_hash set but not used [-Wunused-but-set-variable]

It's never used and can be removed.

Link: http://lkml.kernel.org/r/20190716132110.34836-1-yuehaibing@huawei.com


Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Cc: Mark Fasheh <mark@fasheh.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Changwei Ge <gechangwei@live.cn>
Cc: Gang He <ghe@suse.com>
Cc: Jun Piao <piaojun@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

When running ltp's oom test with kmemleak enabled, the below warning was
triggerred since kernel detects __GFP_NOFAIL & ~__GFP_DIRECT_RECLAIM is
passed in:

  WARNING: CPU: 105 PID: 2138 at mm/page_alloc.c:4608 __alloc_pages_nodemask+0x1c31/0x1d50
  Modules linked in: loop dax_pmem dax_pmem_core ip_tables x_tables xfs virtio_net net_failover virtio_blk failover ata_generic virtio_pci virtio_ring virtio libata
  CPU: 105 PID: 2138 Comm: oom01 Not tainted 5.2.0-next-20190710+ #7
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.10.2-0-g5f4c7b1-prebuilt.qemu-project.org 04/01/2014
  RIP: 0010:__alloc_pages_nodemask+0x1c31/0x1d50
  ...
   kmemleak_alloc+0x4e/0xb0
   kmem_cache_alloc+0x2a7/0x3e0
   mempool_alloc_slab+0x2d/0x40
   mempool_alloc+0x118/0x2b0
   bio_alloc_bioset+0x19d/0x350
   get_swap_bio+0x80/0x230
   __swap_writepage+0x5ff/0xb20

The mempool_alloc_slab() clears __GFP_DIRECT_RECLAIM, however kmemleak
has __GFP_NOFAIL set all the time due to d9570ee3 ("kmemleak:
allow to coexist with fault injection").  But, it doesn't make any sense
to have __GFP_NOFAIL and ~__GFP_DIRECT_RECLAIM specified at the same
time.

According to the discussion on the mailing list, the commit should be
reverted for short term solution.  Catalin Marinas would follow up with
a better solution for longer term.

The failure rate of kmemleak metadata allocation may increase in some
circumstances, but this should be expected side effect.

Link: http://lkml.kernel.org/r/1563299431-111710-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: d9570ee3

 ("kmemleak: allow to coexist with fault injection")
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The kernel-doc parser doesn't handle expressions with %foo*.  Instead,
when an asterisk should be part of a constant, it uses an alternative
notation: `foo*`.

Link: http://lkml.kernel.org/r/7f18c2e0b5e39e6b7eb55ddeb043b8b260b49f2d.1563361575.git.mchehab+samsung@kernel.org


Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull more drm fixes from Daniel Vetter:
 "Dave sends his pull, everyone realizes they've been asleep at the
  wheel and hits send on their own pulls :-/

  Normally I'd just ignore these all because w/e for me and Dave. But
  this time around the latecomers also included drm-intel-fixes, which
  failed to send out a -fixes pull thus far for this release (screwed up
  vacation coverage, despite that 2/3 maintainers were around ... they
  all look appropriately guilty), and that really is overdue to get
  landed.

  And since I had to do a pull request anyway I pulled the other two
  late ones too.

  intel fixes (didn't have any ever since the main merge window pull):
   - gvt fixes (2 cc: stable)
   - fix gpu reset vs mm-shrinker vs wakeup fun (needed a few patches)
   - two gem locking fixes (one cc: stable)
   - pile of misc fixes all over with minor impact, 6 cc: stable, others
     from this window

  exynos:
   - misc minor fixes

  misc:
   - some build/Kconfig fixes
   - regression fix for vm scalability perf test which seems to mostly
     exercise dmesg/console logging ...
   - the vgem cache flush fix for arm64 broke the world on x86, so
     that's reverted again

* tag 'drm-fixes-2019-08-02-1' of git://anongit.freedesktop.org/drm/drm: (42 commits)
  Revert "drm/vgem: fix cache synchronization on arm/arm64"
  drm/exynos: fix missing decrement of retry counter
  drm/exynos: add CONFIG_MMU dependency
  drm/exynos: remove redundant assignment to pointer 'node'
  drm/exynos: using dev_get_drvdata directly
  drm/bochs: Use shadow buffer for bochs framebuffer console
  drm/fb-helper: Instanciate shadow FB if configured in device's mode_config
  drm/fb-helper: Map DRM client buffer only when required
  drm/client: Support unmapping of DRM client buffers
  drm/i915: Only recover active engines
  drm/i915: Add a wakeref getter for iff the wakeref is already active
  drm/i915: Lift intel_engines_resume() to callers
  drm/vgem: fix cache synchronization on arm/arm64
  drm/i810: Use CONFIG_PREEMPTION
  drm/bridge: tc358764: Fix build error
  drm/bridge: lvds-encoder: Fix build error while CONFIG_DRM_KMS_HELPER=m
  drm/i915/gvt: Adding ppgtt to GVT GEM context after shadow pdps settled.
  drm/i915/gvt: grab runtime pm first for forcewake use
  drm/i915/gvt: fix incorrect cache entry for guest page mapping
  drm/i915/gvt: Checking workload's gma earlier
  ...

Pull selinux fix from Paul Moore:
 "One more small fix for a potential memory leak in an error path"

* tag 'selinux-pr-20190801' of git://git.kernel.org/pub/scm/linux/kernel/git/pcmoore/selinux:
  selinux: fix memory leak in policydb_init()

Pull xen fixes from Juergen Gross:

 - a small cleanup

 - a fix for a build error on ARM with some configs

 - a fix of a patch for the Xen gntdev driver

 - three patches for fixing a potential problem in the swiotlb-xen
   driver which Konrad was fine with me carrying them through the Xen
   tree

* tag 'for-linus-5.3a-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/swiotlb: remember having called xen_create_contiguous_region()
  xen/swiotlb: simplify range_straddles_page_boundary()
  xen/swiotlb: fix condition for calling xen_destroy_contiguous_region()
  xen: avoid link error on ARM
  xen/gntdev.c: Replace vm_map_pages() with vm_map_pages_zero()
  xen/pciback: remove set but not used variable 'old_state'

Pull arm64 fixes from Catalin Marinas:

 - Update the compat layer to allow single-byte watchpoints on all
   addresses (similar to the native support)

 - arm_pmu: fix the restoration of the counters on the
   CPU_PM_ENTER_FAILED path

 - Fix build regression with vDSO and Makefile not stripping
   CROSS_COMPILE_COMPAT

 - Fix the CTR_EL0 (cache type register) sanitisation on heterogeneous
   machines (e.g. big.LITTLE)

 - Fix the interrupt controller priority mask value when pseudo-NMIs are
   enabled

 - arm64 kprobes fixes: recovering of the PSTATE.D flag in the
   single-step exception handler, NOKPROBE annotations for
   unwind_frame() and walk_stackframe(), remove unneeded
   rcu_read_lock/unlock from debug handlers

 - Several gcc fall-through warnings

 - Unused variable warnings

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: Make debug exception handlers visible from RCU
  arm64: kprobes: Recover pstate.D in single-step exception handler
  arm64/mm: fix variable 'tag' set but not used
  arm64/mm: fix variable 'pud' set but not used
  arm64: Remove unneeded rcu_read_lock from debug handlers
  arm64: unwind: Prohibit probing on return_address()
  arm64: Lower priority mask for GIC_PRIO_IRQON
  arm64/efi: fix variable 'si' set but not used
  arm64: cpufeature: Fix feature comparison for CTR_EL0.{CWG,ERG}
  arm64: vdso: Fix Makefile regression
  arm64: module: Mark expected switch fall-through
  arm64: smp: Mark expected switch fall-through
  arm64: hw_breakpoint: Fix warnings about implicit fallthrough
  drivers/perf: arm_pmu: Fix failure path in PM notifier
  arm64: compat: Allow single-byte watchpoints on all addresses

Pull parisc fixes from Helge Deller:
 "A few small fixes for the parisc architecture:

   - Fix fall-through warnings in parisc math emu code

   - Fix vmlinuz linking failure with debug-enabled kernels

   - Fix a race condition in kernel live-patching code

   - Add missing archclean Makefile target & defconfig adjustments"

* 'parisc-5.3-4' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Add archclean Makefile target
  parisc: Strip debug info from kernel before creating compressed vmlinuz
  parisc: Fix build of compressed kernel even with debug enabled
  parisc: fix race condition in patching code
  parisc: rename default_defconfig to defconfig
  parisc: Fix fall-through warnings in fpudispatch.c
  parisc: Mark expected switch fall-throughs in fault.c

Pull s390 updates from Vasily Gorbik:

 - Default configs updates

 - Minor qdio cleanup

 - Sparse warnings fixes

 - Implicit-fallthrough warnings fixes

* tag 's390-5.3-4' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux:
  s390/zcrypt: adjust switch fall through comments for -Wimplicit-fallthrough
  vfio-ccw: make vfio_ccw_async_region_ops static
  s390/3215: add switch fall through comment for -Wimplicit-fallthrough
  s390/tape: add fallthrough annotations
  s390/mm: add fallthrough annotations
  s390/mm: make gmap_test_and_clear_dirty_pmd static
  s390/kexec: add missing include to machine_kexec_reloc.c
  s390/perf: make cf_diag_csd static
  s390/lib: add missing include
  s390/boot: add missing declarations and includes
  s390: update configs
  s390: clean up qdio.h

Pull SCSI fixes from James Bottomley:
 "Seven fixes to four drivers with no core changes.

  The mpt3sas one is theoretical until we get a CPU that goes up to 64
  bits physical, the qla2xxx one fixes an oops in a driver
  initialization error leg and the others are mostly cosmetic"

[ The fcoe patches may be worth highlighting - they may be "just"
  cleanups, but they simplify and fix the odd fc_rport_priv structure
  handling rules so that the new gcc-9 warnings about memset crossing
  structure boundaries are gone.

  The old code was hard for humans to understand too, and really
  confused the compiler sanity checks  - Linus ]

* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
  scsi: qla2xxx: Fix possible fcport null-pointer dereferences
  scsi: mpt3sas: Use 63-bit DMA addressing on SAS35 HBA
  scsi: hpsa: remove printing internal cdb on tag collision
  scsi: hpsa: correct scsi command status issue after reset
  scsi: fcoe: pass in fcoe_rport structure instead of fc_rport_priv
  scsi: fcoe: Embed fc_rport_priv in fcoe_rport structure
  scsi: libfc: Whitespace cleanup in libfc.h

Pull block fixes from Jens Axboe:
 "Here's a small collection of fixes that should go into this series.
  This contains:

   - io_uring potential use-after-free fix (Jackie)

   - loop regression fix (Jan)

   - O_DIRECT fragmented bio regression fix (Damien)

   - Mark Denis as the new floppy maintainer (Denis)

   - ataflop switch fall-through annotation (Gustavo)

   - libata zpodd overflow fix (Kees)

   - libata ahci deferred probe fix (Miquel)

   - nbd invalidation BUG_ON() fix (Munehisa)

   - dasd endless loop fix (Stefan)"

* tag 'for-linus-20190802' of git://git.kernel.dk/linux-block:
  s390/dasd: fix endless loop after read unit address configuration
  block: Fix __blkdev_direct_IO() for bio fragments
  MAINTAINERS: floppy: take over maintainership
  nbd: replace kill_bdev() with __invalidate_device() again
  ata: libahci: do not complain in case of deferred probe
  io_uring: fix KASAN use after free in io_sq_wq_submit_work
  loop: Fix mount(2) failure due to race with LOOP_SET_FD
  libata: zpodd: Fix small read overflow in zpodd_get_mech_type()
  ataflop: Mark expected switch fall-through

Merge tag 'for-5.3/dm-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper fixes from Mike Snitzer:
 "Fix NULL pointer and various whitespace issues with DM's recent DAX
  code changes from commit in 5.3 merge"

* tag 'for-5.3/dm-fixes-1' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm table: fix various whitespace issues with recent DAX code
  dm table: fix dax_dev NULL dereference in device_synchronous()

Pull rdma fixes from Doug Ledford:
 "Here's our second -rc pull request. Nothing particularly special in
  this one. The client removal deadlock fix is kindy tricky, but we had
  multiple eyes on it and no one could find a fault in it. A couple
  Spectre V1 fixes too. Otherwise, all just normal -rc fodder:

   - A couple Spectre V1 fixes (umad, hfi1)

   - Fix a tricky deadlock in the rdma core code with refcounting
     instead of locks (client removal patches)

   - Build errors (hns)

   - Fix a scheduling while atomic issue (mlx5)

   - Use after free fix (mad)

   - Fix error path return code (hns)

   - Null deref fix (siw_crypto_hash)

   - A few other misc. minor fixes"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
  RDMA/hns: Fix error return code in hns_roce_v1_rsv_lp_qp()
  RDMA/mlx5: Release locks during notifier unregister
  IB/hfi1: Fix Spectre v1 vulnerability
  IB/mad: Fix use-after-free in ib mad completion handling
  RDMA/restrack: Track driver QP types in resource tracker
  IB/mlx5: Fix MR registration flow to use UMR properly
  RDMA/devices: Remove the lock around remove_client_context
  RDMA/devices: Do not deadlock during client removal
  IB/core: Add mitigation for Spectre V1
  Do not dereference 'siw_crypto_shash' before checking
  RDMA/qedr: Fix the hca_type and hca_rev returned in device attributes
  RDMA/hns: Fix build error

Pull btrfs fixes from David Sterba:

 - tiny race window during 2 transactions aborting at the same time can
   accidentally lead to a commit

 - regression fix, possible deadlock during fiemap

 - fix for an old bug when incremental send can fail on a file that has
   been deduplicated in a special way

* tag 'for-5.3-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  Btrfs: fix deadlock between fiemap and transaction commits
  Btrfs: fix race leading to fs corruption after transaction abort
  Btrfs: fix incremental send failure after deduplication

Pull gfs2 fix from Andreas Gruenbacher:
 "Fix gfs2 cluster coherency bug"

* tag 'gfs2-v5.3-rc2.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2:
  gfs2: Inode dirtying fix

Pull power management fix from Rafael Wysocki:
 "Fix recent regression affecting ACPI device power management"

* tag 'pm-5.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI: PM: Fix regression in acpi_device_set_power()

Pull sound fixes from Takashi Iwai:

 - A further fix for syzcaller issues with USB-audio, addressing NULL
   dereference that was introduced by the recent fix

 - Avoid a long delay at boot with HD-audio when i915 module was built
   but not installed, found on some Debian systems

 - A fix of small race window at PCM draining

* tag 'sound-5.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound:
  ALSA: usb-audio: Fix gpf in snd_usb_pipe_sanity_check
  ALSA: pcm: fix lost wakeup event scenarios in snd_pcm_drain
  ALSA: hda: Fix 1-minute detection delay when i915 module is not available

Pull drm fixes from Dave Airlie:
 "Thanks to Daniel for handling the email the last couple of weeks, flus
  and break-ins combined to derail me. Surprised nothing materialised
  today to take me out again.

  Just more amdgpu navi fixes, msm fixes and a single nouveau regression
  fix:

  amdgpu:
   - navi10 temperature and pstate fixes
   - vcn dynamic power management fix
   - CS ioctl error handling fix
   - debugfs info leak fix
   - amdkfd VegaM fix

  msm:
   - dma sync call fix
   - mdp5 dsi command mode fix
   - fall-through fixes
   - disabled GPU fix

  nouveau:
   - regression fix for displayport MST support"

* tag 'drm-fixes-2019-08-02' of git://anongit.freedesktop.org/drm/drm:
  drm/nouveau: Only release VCPI slots on mode changes
  drm: msm: Fix add_gpu_components
  drm/msm: Annotate intentional switch statement fall throughs
  drm/msm: add support for per-CRTC max_vblank_count on mdp5
  drm/msm: Use the correct dma_sync calls in msm_gem
  drm/amd/powerplay: correct UVD/VCE/VCN power status retrieval
  drm/amd/powerplay: correct Navi10 VCN powergate control (v2)
  drm/amd/powerplay: support VCN powergate status retrieval for SW SMU
  drm/amd/powerplay: support VCN powergate status retrieval on Raven
  drm/amd/powerplay: add new sensor type for VCN powergate status
  drm/amdgpu: fix a potential information leaking bug
  drm/amdgpu: fix error handling in amdgpu_cs_process_fence_dep
  drm/amd/powerplay: enable SW SMU reset functionality
  drm/amd/powerplay: fix null pointer dereference around dpm state relates
  drm/amdgpu/powerplay: use proper revision id for navi
  drm/amd/powerplay: fix temperature granularity error in smu11
  drm/amd/powerplay: add callback function of get_thermal_temperature_range
  drm/amdkfd: Fix byte align on VegaM

Pull clk fixes from Stephen Boyd:
 "A few fixes for code that came in during the merge window or that
  started getting exercised differently this time around:

   - Select regmap MMIO kconfig in spreadtrum driver to avoid compile
     errors

   - Complete kerneldoc on devm_clk_bulk_get_optional()

   - Register an essential clk earlier on mediatek mt8183 SoCs so the
     clocksource driver can use it

   - Fix divisor math in the at91 driver

   - Plug a race in Renesas reset control logic"

* tag 'clk-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/clk/linux:
  clk: renesas: cpg-mssr: Fix reset control race condition
  clk: sprd: Select REGMAP_MMIO to avoid compile errors
  clk: mediatek: mt8183: Register 13MHz clock earlier for clocksource
  clk: Add missing documentation of devm_clk_bulk_get_optional() argument
  clk: at91: generated: Truncate divisor to GENERATED_MAX_DIV + 1

Pull arm swiotlb support from Christoph Hellwig:
 "This fixes a cascade of regressions that originally started with the
  addition of the ia64 port, but only got fatal once we removed most
  uses of block layer bounce buffering in Linux 4.18.

  The reason is that while the original i386/PAE code that was the first
  architecture that supported > 4GB of memory without an iommu decided
  to leave bounce buffering to the subsystems, which in those days just
  mean block and networking as no one else consumed arbitrary userspace
  memory.

  Later with ia64, x86_64 and other ports we assumed that either an
  iommu or something that fakes it up ("software IOTLB" in beautiful
  Intel speak) is present and that subsystems can rely on that for
  dealing with addressing limitations in devices. Except that the ARM
  LPAE scheme that added larger physical address to 32-bit ARM did not
  follow that scheme and thus only worked by chance and only for block
  and networking I/O directly to highmem.

  Long story, short fix - add swiotlb support to arm when build for LPAE
  platforms, which actuallys turns out to be pretty trivial with the
  modern dma-direct / swiotlb code to fix the Linux 4.18-ish regression"

* tag 'arm-swiotlb-5.3' of git://git.infradead.org/users/hch/dma-mapping:
  arm: use swiotlb for bounce buffering on LPAE configs
  dma-mapping: check pfn validity in dma_common_{mmap,get_sgtable}