Pull block fixes from Jens Axboe:

 - Use import_uuid() where appropriate (Andy)

 - bcache fixes (Coly, Mauricio, Zhiqiang)

 - blktrace sparse warnings fix (Jan)

 - blktrace concurrent setup fix (Luis)

 - blkdev_get use-after-free fix (Jason)

 - Ensure all blk-mq maps are updated (Weiping)

 - Loop invalidate bdev fix (Zheng)

* tag 'block-5.8-2020-06-19' of git://git.kernel.dk/linux-block:
  block: make function 'kill_bdev' static
  loop: replace kill_bdev with invalidate_bdev
  partitions/ldm: Replace uuid_copy() with import_uuid() where it makes sense
  block: update hctx map when use multiple maps
  blktrace: Avoid sparse warnings when assigning q->blk_trace
  blktrace: break out of blktrace setup on concurrent calls
  block: Fix use-after-free in blkdev_get()
  trace/events/block.h: drop kernel-doc for dropped function parameter
  blk-mq: Remove redundant 'return' statement
  bcache: pr_info() format clean up in bcache_device_init()
  bcache: use delayed kworker fo asynchronous devices registration
  bcache: check and adjust logical block size for backing devices
  bcache: fix potential deadlock problem in btree_gc_coalesce

Pull libata fixes from Jens Axboe:
 "A few minor changes that should go into this release"

* tag 'libata-5.8-2020-06-19' of git://git.kernel.dk/linux-block:
  libata: Use per port sync for detach
  ata/libata: Fix usage of page address by page_address in ata_scsi_mode_select_xlat function
  sata_rcar: handle pm_runtime_get_sync failure cases

Pull drm fixes from Dave Airlie:
 "Just i915 and amd here.

  i915 has some workaround movement so they get applied at the right
  times, and a timeslicing fix, along with some display fixes.

  AMD has a few display floating point fix and a devcgroup fix for
  amdkfd.

  i915:
   - Fix for timeslicing and virtual engines/unpremptable requests (+ 1
     dependency patch)
   - Fixes into TypeC register programming and interrupt storm detecting
   - Disable DIP on MST ports with the transcoder clock still on
   - Avoid missing GT workarounds at reset for HSW and older gens
   - Fix for unwinding multiple requests missing force restore
   - Fix encoder type check for DDI vswing sequence
   - Build warning fixes

  amdgpu:
   - Fix kvfree/kfree mixup
   - Fix hawaii device id in powertune configuration
   - Display FP fixes
   - Documentation fixes

  amdkfd:
   - devcgroup check fix"

* tag 'drm-fixes-2020-06-19' of git://anongit.freedesktop.org/drm/drm: (23 commits)
  drm/amdgpu: fix documentation around busy_percentage
  drm/amdgpu/pm: update comment to clarify Overdrive interfaces
  drm/amdkfd: Use correct major in devcgroup check
  drm/i915/display: Fix the encoder type check
  drm/i915/icl+: Fix hotplug interrupt disabling after storm detection
  drm/i915/gt: Move gen4 GT workarounds from init_clock_gating to workarounds
  drm/i915/gt: Move ilk GT workarounds from init_clock_gating to workarounds
  drm/i915/gt: Move snb GT workarounds from init_clock_gating to workarounds
  drm/i915/gt: Move vlv GT workarounds from init_clock_gating to workarounds
  drm/i915/gt: Move ivb GT workarounds from init_clock_gating to workarounds
  drm/i915/gt: Move hsw GT workarounds from init_clock_gating to workarounds
  drm/i915/icl: Disable DIP on MST ports with the transcoder clock still on
  drm/i915/gt: Incrementally check for rewinding
  drm/i915/tc: fix the reset of ln0
  drm/i915/gt: Prevent timeslicing into unpreemptable requests
  drm/i915/selftests: Restore to default heartbeat
  drm/i915: work around false-positive maybe-uninitialized warning
  drm/i915/pmu: avoid an maybe-uninitialized warning
  drm/i915/gt: Incorporate the virtual engine into timeslicing
  drm/amd/display: Rework dsc to isolate FPU operations
  ...

Pull ceph fixes from Ilya Dryomov:
 "An important follow-up for replica reads support that went into -rc1
  and two target_copy() fixups"

* tag 'ceph-for-5.8-rc2' of git://github.com/ceph/ceph-client:
  libceph: don't omit used_replica in target_copy()
  libceph: don't omit recovery_deletes in target_copy()
  libceph: move away from global osd_req_flags

Pull arm64 fixes from Will Deacon:
 "Unfortunately, we still have a number of outstanding issues so there
  will be more fixes to come, but this lot are a good start.

   - Fix handling of watchpoints triggered by uaccess routines

   - Fix initialisation of gigantic pages for CMA buffers

   - Raise minimum clang version for BTI to avoid miscompilation

   - Fix data race in SVE vector length configuration code

   - Ensure address tags are ignored in kern_addr_valid()

   - Dump register state on fatal BTI exception

   - kexec_file() cleanup to use struct_size() macro"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64: hw_breakpoint: Don't invoke overflow handler on uaccess watchpoints
  arm64: kexec_file: Use struct_size() in kmalloc()
  arm64: mm: reserve hugetlb CMA after numa_init
  arm64: bti: Require clang >= 10.0.1 for in-kernel BTI support
  arm64: sve: Fix build failure when ARM64_SVE=y and SYSCTL=n
  arm64: pgtable: Clear the GP bit for non-executable kernel pages
  arm64: mm: reset address tag set by kasan sw tagging
  arm64: traps: Dump registers prior to panic() in bad_mode()
  arm64/sve: Eliminate data races on sve_default_vl
  docs/arm64: Fix typo'd #define in sve.rst
  arm64: remove TEXT_OFFSET randomization

Pull flex-array size helper from Kees Cook:
 "During the treewide clean-ups of zero-length "flexible arrays", the
  struct_size() helper was heavily used, but it was noticed that many
  times it would have been nice to have an additional helper to get the
  size of just the flexible array itself.

  This need appears to be even more common when cleaning up the 1-byte
  array "flexible arrays", so Gustavo implemented it.

  I'd love to get this landed early so it can be used during the v5.9
  dev cycle to ease the 1-byte array cleanups."

* tag 'overflow-v5.8-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  overflow.h: Add flex_array_size() helper

Pull perf tooling fixes from Arnaldo Carvalho de Melo:

 - Update various UAPI headers, some automatically adding support for a
   new MSR and the faccess2 syscall.

 - Fix corner case NULL deref in the histograms code.

 - Fix corner case NULL deref in 'perf stat' aggregation code.

 - Fix array pointer deref and old style declaration in the parsing of
   events.

 - Fix segfault when processing ZSTD compressed perf.data files in 'perf
   script' due to lack of initialization of the ZSTD library.

 - Handle __attribute__((user)) in libtraceevent fixing the parsing of
   syscall tracepoints with user buffers.

 - Make libtraevent aware of __builtin_expect() appearing in tracepoint
   fields.

 - Make the BPF prologue generation use bpf_probe_read_{user,kernel}().

 - Fix the '@user' attribute parsing in kprobes variables in 'perf
   probe'.

 - Fix error message when asking for -fsanitize=address without required
   libraries.

* tag 'perf-tools-fixes-2020-06-02' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux: (22 commits)
  perf build: Fix error message when asking for -fsanitize=address without required libraries
  tools lib traceevent: Add handler for __builtin_expect()
  tools lib traceevent: Handle __attribute__((user)) in field names
  tools lib traceevent: Add append() function helper for appending strings
  tools headers UAPI: Sync linux/fs.h with the kernel sources
  tools include UAPI: Sync linux/vhost.h with the kernel sources
  tools arch x86: Sync the msr-index.h copy with the kernel sources
  perf script: Initialize zstd_data
  perf pmu: Remove unused declaration
  perf parse-events: Fix an old style declaration
  perf parse-events: Fix an incompatible pointer
  perf bpf: Fix bpf prologue generation
  perf probe: Fix user attribute access in kprobes
  perf stat: Fix NULL pointer dereference
  perf report: Fix NULL pointer dereference in hists__fprintf_nr_sample_events()
  tools headers UAPI: Sync kvm.h headers with the kernel sources
  tools headers UAPI: Sync drm/i915_drm.h with the kernel sources
  tools headers UAPI: Sync linux/fscrypt.h with the kernel sources
  perf beauty: Add support to STATX_MNT_ID in the 'statx' syscall 'mask' argument
  tools headers uapi: Sync linux/stat.h with the kernel sources
  ...

Merge tag 'amd-drm-fixes-5.8-2020-06-17' of git://people.freedesktop.org/~agd5f/linux into drm-fixes

amd-drm-fixes-5.8-2020-06-17:

amdgpu:
- Fix kvfree/kfree mixup
- Fix hawaii device id in powertune configuration
- Display FP fixes
- Documentation fixes

amdkfd:
- devcgroup check fix
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Alex Deucher <alexdeucher@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200617220733.3773183-1-alexander.deucher@amd.com

Merge tag 'drm-intel-fixes-2020-06-18' of git://anongit.freedesktop.org/drm/drm-intel into drm-fixes

- Fix for timeslicing and virtual engines/unpremptable requests
  (+ 1 dependency patch)
- Fixes into TypeC register programming and interrupt storm detecting
- Disable DIP on MST ports with the transcoder clock still on
- Avoid missing GT workarounds at reset for HSW and older gens
- Fix for unwinding multiple requests missing force restore
- Fix encoder type check for DDI vswing sequence
- Build warning fixes
Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200618124659.GA12342@jlahtine-desk.ger.corp.intel.com

Merge non-faulting memory access cleanups from Christoph Hellwig:
 "Andrew and I decided to drop the patches implementing your suggested
  rename of the probe_kernel_* and probe_user_* helpers from -mm as
  there were way to many conflicts.

  After -rc1 might be a good time for this as all the conflicts are
  resolved now"

This also adds a type safety checking patch on top of the renaming
series to make the subtle behavioral difference between 'get_user()' and
'get_kernel_nofault()' less potentially dangerous and surprising.

* emailed patches from Christoph Hellwig <hch@lst.de>:
  maccess: make get_kernel_nofault() check for minimal type compatibility
  maccess: rename probe_kernel_address to get_kernel_nofault
  maccess: rename probe_user_{read,write} to copy_{from,to}_user_nofault
  maccess: rename probe_kernel_{read,write} to copy_{from,to}_kernel_nofault

Now that we've renamed probe_kernel_address() to get_kernel_nofault()
and made it look and behave more in line with get_user(), some of the
subtle type behavior differences end up being more obvious and possibly
dangerous.

When you do

        get_user(val, user_ptr);

the type of the access comes from the "user_ptr" part, and the above
basically acts as

        val = *user_ptr;

by design (except, of course, for the fact that the actual dereference
is done with a user access).

Note how in the above case, the type of the end result comes from the
pointer argument, and then the value is cast to the type of 'val' as
part of the assignment.

So the type of the pointer is ultimately the more important type both
for the access itself.

But 'get_kernel_nofault()' may now _look_ similar, but it behaves very
differently.  When you do

        get_kernel_nofault(val, kernel_ptr);

it behaves like

        val = *(typeof(val) *)kernel_ptr;

except, of course, for the fact that the actual dereference is done with
exception handling so that a faulting access is suppressed and returned
as the error code.

But note how different the casting behavior of the two superficially
similar accesses are: one does the actual access in the size of the type
the pointer points to, while the other does the access in the size of
the target, and ignores the pointer type entirely.

Actually changing get_kernel_nofault() to act like get_user() is almost
certainly the right thing to do eventually, but in the meantime this
patch adds logit to at least verify that the pointer type is compatible
with the type of the result.

In many cases, this involves just casting the pointer to 'void *' to
make it obvious that the type of the pointer is not the important part.
It's not how 'get_user()' acts, but at least the behavioral difference
is now obvious and explicit.

Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Better describe what this helper does, and match the naming of
copy_from_kernel_nofault.

Also switch the argument order around, so that it acts and looks
like get_user().
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Currently, address spaces in warnings are displayed as '<asn:X>' with
'X' being the address space's arbitrary number.

But since sparse v0.6.0-rc1 (late December 2018), sparse allows you to
define the address spaces using an identifier instead of a number.  This
identifier is then directly used in the warnings.

So, use the identifiers '__user', '__iomem', '__percpu' & '__rcu' for
the corresponding address spaces.  The default address space, __kernel,
being not displayed in warnings, stays defined as '0'.

With this change, warnings that used to be displayed as:

	cast removes address space '<asn:1>' of expression
	... void [noderef] <asn:2> *

will now be displayed as:

	cast removes address space '__user' of expression
	... void [noderef] __iomem *

This also moves the __kernel annotation to be the first one, since it is
quite different from the others because it's the default one, and so:

 - it's never displayed

 - it's normally not needed, nor in type annotations, nor in cast
   between address spaces. The only time it's needed is when it's
   combined with a typeof to express "the same type as this one but
   without the address space"

 - it can't be defined with a name, '0' must be used.

So, it seemed strange to me to have it in the middle of the other
ones.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Acked-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kill_bdev does not have any external user, so make it static.
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When a filesystem is mounted on a loop device and on a loop ioctl
LOOP_SET_STATUS64, because of kill_bdev, buffer_head mappings are getting
destroyed.
kill_bdev
  truncate_inode_pages
    truncate_inode_pages_range
      do_invalidatepage
        block_invalidatepage
          discard_buffer  -->clear BH_Mapped flag

sb_bread
  __bread_gfp
  bh = __getblk_gfp
  -->discard_buffer clear BH_Mapped flag
  __bread_slow
    submit_bh
      submit_bh_wbc
        BUG_ON(!buffer_mapped(bh))  --> hit this BUG_ON

Fixes: 5db470e2 ("loop: drop caches if offset or block_size are changed")
Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Commit 130f4caf ("libata: Ensure ata_port probe has completed before
detach") may cause system freeze during suspend.

Using async_synchronize_full() in PM callbacks is wrong, since async
callbacks that are already scheduled may wait for not-yet-scheduled
callbacks, causes a circular dependency.

Instead of using big hammer like async_synchronize_full(), use async
cookie to make sure port probe are synced, without affecting other
scheduled PM callbacks.

Fixes: 130f4caf ("libata: Ensure ata_port probe has completed before detach")
Suggested-by: John Garry <john.garry@huawei.com>
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Tested-by: John Garry <john.garry@huawei.com>
BugLink: https://bugs.launchpad.net/bugs/1867983Signed-off-by: Jens Axboe <axboe@kernel.dk>

There is a specific API to treat raw data as UUID, i.e. import_uuid().
Use it instead of uuid_copy() with explicit casting.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

When build perf with ASan or UBSan, if libasan or libubsan can not find,
the feature-glibc is 0 and there exists the following error log which is
wrong, because we can find gnu/libc-version.h in /usr/include,
glibc-devel is also installed.

  [yangtiezhu@linux perf]$ make DEBUG=1 EXTRA_CFLAGS='-fno-omit-frame-pointer -fsanitize=address'
    BUILD:   Doing 'make -j4' parallel build
    HOSTCC   fixdep.o
    HOSTLD   fixdep-in.o
    LINK     fixdep
  <stdin>:1:0: warning: -fsanitize=address and -fsanitize=kernel-address are not supported for this target
  <stdin>:1:0: warning: -fsanitize=address not supported for this target

  Auto-detecting system features:
  ...                         dwarf: [ OFF ]
  ...            dwarf_getlocations: [ OFF ]
  ...                         glibc: [ OFF ]
  ...                          gtk2: [ OFF ]
  ...                      libaudit: [ OFF ]
  ...                        libbfd: [ OFF ]
  ...                        libcap: [ OFF ]
  ...                        libelf: [ OFF ]
  ...                       libnuma: [ OFF ]
  ...        numa_num_possible_cpus: [ OFF ]
  ...                       libperl: [ OFF ]
  ...                     libpython: [ OFF ]
  ...                     libcrypto: [ OFF ]
  ...                     libunwind: [ OFF ]
  ...            libdw-dwarf-unwind: [ OFF ]
  ...                          zlib: [ OFF ]
  ...                          lzma: [ OFF ]
  ...                     get_cpuid: [ OFF ]
  ...                           bpf: [ OFF ]
  ...                        libaio: [ OFF ]
  ...                       libzstd: [ OFF ]
  ...        disassembler-four-args: [ OFF ]

  Makefile.config:393: *** No gnu/libc-version.h found, please install glibc-dev[el].  Stop.
  Makefile.perf:224: recipe for target 'sub-make' failed
  make[1]: *** [sub-make] Error 2
  Makefile:69: recipe for target 'all' failed
  make: *** [all] Error 2
  [yangtiezhu@linux perf]$ ls /usr/include/gnu/libc-version.h
  /usr/include/gnu/libc-version.h

After install libasan and libubsan, the feature-glibc is 1 and the build
process is success, so the cause is related with libasan or libubsan, we
should check them and print an error log to reflect the reality.

Committer testing:

  $ rm -rf /tmp/build/perf ; mkdir -p /tmp/build/perf
  $ make DEBUG=1 EXTRA_CFLAGS='-fno-omit-frame-pointer -fsanitize=address' O=/tmp/build/perf -C tools/perf/ install-bin
  make: Entering directory '/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j12' parallel build
    HOSTCC   /tmp/build/perf/fixdep.o
    HOSTLD   /tmp/build/perf/fixdep-in.o
    LINK     /tmp/build/perf/fixdep

  Auto-detecting system features:
  ...                         dwarf: [ OFF ]
  ...            dwarf_getlocations: [ OFF ]
  ...                         glibc: [ OFF ]
  ...                          gtk2: [ OFF ]
  ...                        libbfd: [ OFF ]
  ...                        libcap: [ OFF ]
  ...                        libelf: [ OFF ]
  ...                       libnuma: [ OFF ]
  ...        numa_num_possible_cpus: [ OFF ]
  ...                       libperl: [ OFF ]
  ...                     libpython: [ OFF ]
  ...                     libcrypto: [ OFF ]
  ...                     libunwind: [ OFF ]
  ...            libdw-dwarf-unwind: [ OFF ]
  ...                          zlib: [ OFF ]
  ...                          lzma: [ OFF ]
  ...                     get_cpuid: [ OFF ]
  ...                           bpf: [ OFF ]
  ...                        libaio: [ OFF ]
  ...                       libzstd: [ OFF ]
  ...        disassembler-four-args: [ OFF ]

  Makefile.config:401: *** No libasan found, please install libasan.  Stop.
  make[1]: *** [Makefile.perf:231: sub-make] Error 2
  make: *** [Makefile:70: all] Error 2
  make: Leaving directory '/home/acme/git/perf/tools/perf'
  $
  $
  $ sudo dnf install libasan
  <SNIP>
  Installed:
    libasan-9.3.1-2.fc31.x86_64
  $
  $
  $ make DEBUG=1 EXTRA_CFLAGS='-fno-omit-frame-pointer -fsanitize=address' O=/tmp/build/perf -C tools/perf/ install-bin
  make: Entering directory '/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j12' parallel build

  Auto-detecting system features:
  ...                         dwarf: [ on  ]
  ...            dwarf_getlocations: [ on  ]
  ...                         glibc: [ on  ]
  ...                          gtk2: [ on  ]
  ...                        libbfd: [ on  ]
  ...                        libcap: [ on  ]
  ...                        libelf: [ on  ]
  ...                       libnuma: [ on  ]
  ...        numa_num_possible_cpus: [ on  ]
  ...                       libperl: [ on  ]
  ...                     libpython: [ on  ]
  ...                     libcrypto: [ on  ]
  ...                     libunwind: [ on  ]
  ...            libdw-dwarf-unwind: [ on  ]
  ...                          zlib: [ on  ]
  ...                          lzma: [ on  ]
  ...                     get_cpuid: [ on  ]
  ...                           bpf: [ on  ]
  ...                        libaio: [ on  ]
  ...                       libzstd: [ on  ]
  ...        disassembler-four-args: [ on  ]
   <SNIP>
    CC       /tmp/build/perf/util/pmu-flex.o
    FLEX     /tmp/build/perf/util/expr-flex.c
    CC       /tmp/build/perf/util/expr-bison.o
    CC       /tmp/build/perf/util/expr.o
    CC       /tmp/build/perf/util/expr-flex.o
    CC       /tmp/build/perf/util/parse-events-flex.o
    CC       /tmp/build/perf/util/parse-events.o
    LD       /tmp/build/perf/util/intel-pt-decoder/perf-in.o
    LD       /tmp/build/perf/util/perf-in.o
    LD       /tmp/build/perf/perf-in.o
    LINK     /tmp/build/perf/perf
  <SNIP>
    INSTALL  python-scripts
    INSTALL  perf_completion-script
    INSTALL  perf-tip
  make: Leaving directory '/home/acme/git/perf/tools/perf'
  $ ldd ~/bin/perf | grep asan
  	libasan.so.5 => /lib64/libasan.so.5 (0x00007f0904164000)
  $

And if we rebuild without -fsanitize-address:

  $ rm -rf /tmp/build/perf ; mkdir -p /tmp/build/perf
  $ make O=/tmp/build/perf -C tools/perf/ install-bin
  make: Entering directory '/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j12' parallel build
    HOSTCC   /tmp/build/perf/fixdep.o
    HOSTLD   /tmp/build/perf/fixdep-in.o
    LINK     /tmp/build/perf/fixdep

  Auto-detecting system features:
  ...                         dwarf: [ on  ]
  ...            dwarf_getlocations: [ on  ]
  ...                         glibc: [ on  ]
  ...                          gtk2: [ on  ]
  ...                        libbfd: [ on  ]
  ...                        libcap: [ on  ]
  ...                        libelf: [ on  ]
  ...                       libnuma: [ on  ]
  ...        numa_num_possible_cpus: [ on  ]
  ...                       libperl: [ on  ]
  ...                     libpython: [ on  ]
  ...                     libcrypto: [ on  ]
  ...                     libunwind: [ on  ]
  ...            libdw-dwarf-unwind: [ on  ]
  ...                          zlib: [ on  ]
  ...                          lzma: [ on  ]
  ...                     get_cpuid: [ on  ]
  ...                           bpf: [ on  ]
  ...                        libaio: [ on  ]
  ...                       libzstd: [ on  ]
  ...        disassembler-four-args: [ on  ]

    GEN      /tmp/build/perf/common-cmds.h
    CC       /tmp/build/perf/exec-cmd.o
  <SNIP>
    INSTALL  perf_completion-script
    INSTALL  perf-tip
  make: Leaving directory '/home/acme/git/perf/tools/perf'
  $ ldd ~/bin/perf | grep asan
  $
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: tiezhu yang <yangtiezhu@loongson.cn>
Cc: xuefeng li <lixuefeng@loongson.cn>
Link: http://lore.kernel.org/lkml/1592445961-28044-1-git-send-email-yangtiezhu@loongson.cnSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

In order to move pointer checks like IS_ERR_VALUE() out of the hotpath
and into the reader path of a trace event, user space tools need to be
able to parse that. IS_ERR_VALUE() is defined as:

 #define IS_ERR_VALUE() unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO)

Which eventually turns into:

  __builtin_expect(!!((unsigned long)(void *)(x) >= (unsigned long)-4095), 0)

Now the traceevent parser can handle most of that except for the
__builtin_expect(), which needs to be added.

Link: https://lore.kernel.org/linux-mm/20200320055823.27089-3-jaewon31.kim@samsung.com/Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jaewon Kim <jaewon31.kim@samsung.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org
Cc: linux-trace-devel@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200324200956.821799393@goodmis.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Commit c61f13ea ("gcc-plugins: Add structleak for more stack
initialization") added "__attribute__((user))" to the user when
stackleak detector is enabled. This now appears in the field format of
system call trace events for system calls that have user buffers. The
"__attribute__((user))" breaks the parsing in libtraceevent. That needs
to be handled.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jaewon Kim <jaewon31.kim@samsung.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: linux-mm@kvack.org
Cc: linux-trace-devel@vger.kernel.org
Link: http://lore.kernel.org/lkml/20200324200956.663647256@goodmis.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

There's several locations that open code realloc and strcat() to append
text to strings. Add an append() function that takes a delimiter and a
string to append to another string.
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jaewon Lim <jaewon31.kim@samsung.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Kook <keescook@chromium.org>
Cc: linux-mm@kvack.org
Cc: linux-trace-devel@vger.kernel.org
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lore.kernel.org/lkml/20200324200956.515118403@goodmis.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Unprivileged memory accesses generated by the so-called "translated"
instructions (e.g. STTR) at EL1 can cause EL0 watchpoints to fire
unexpectedly if kernel debugging is enabled. In such cases, the
hw_breakpoint logic will invoke the user overflow handler which will
typically raise a SIGTRAP back to the current task. This is futile when
returning back to the kernel because (a) the signal won't have been
delivered and (b) userspace can't handle the thing anyway.

Avoid invoking the user overflow handler for watchpoints triggered by
kernel uaccess routines, and instead single-step over the faulting
instruction as we would if no overflow handler had been installed.

(Fixes tag identifies the introduction of unprivileged memory accesses,
 which exposed this latent bug in the hw_breakpoint code)

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Fixes: 57f4959b ("arm64: kernel: Add support for User Access Override")
Reported-by: Luis Machado <luis.machado@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>

Make use of the struct_size() helper instead of an open-coded version
in order to avoid any potential type mistakes.

This code was detected with the help of Coccinelle and, audited and
fixed manually.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200617213407.GA1385@embeddedorSigned-off-by: Will Deacon <will@kernel.org>

hugetlb_cma_reserve() is called at the wrong place. numa_init has not been
done yet. so all reserved memory will be located at node0.

Fixes: cf11e85f ("mm: hugetlb: optionally allocate gigantic hugepages using cma")
Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Roman Gushchin <guro@fb.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20200617215828.25296-1-song.bao.hua@hisilicon.comSigned-off-by: Will Deacon <will@kernel.org>

There is an issue when tune the number for read and write queues,
if the total queue count was not changed. The hctx->type cannot
be updated, since __blk_mq_update_nr_hw_queues will return directly
if the total queue count has not been changed.

Reproduce:

dmesg | grep "default/read/poll"
[    2.607459] nvme nvme0: 48/0/0 default/read/poll queues
cat /sys/kernel/debug/block/nvme0n1/hctx*/type | sort | uniq -c
     48 default

tune the write queues to 24:
echo 24 > /sys/module/nvme/parameters/write_queues
echo 1 > /sys/block/nvme0n1/device/reset_controller

dmesg | grep "default/read/poll"
[  433.547235] nvme nvme0: 24/24/0 default/read/poll queues

cat /sys/kernel/debug/block/nvme0n1/hctx*/type | sort | uniq -c
     48 default

The driver's hardware queue mapping is not same as block layer.
Signed-off-by: Weiping Zhang <zhangweiping@didiglobal.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Add rename the gpu busy percentage for consistency and
add the mem busy percentage documentation.
Reviewed-by: Evan Quan <evan.quan@amd.com>
Reviewed-by: Nirmoy Das <nirmoy.das@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Vega10 and previous asics use one interface, vega20 and newer
use another.
Reviewed-by: Evan Quan <evan.quan@amd.com>
Acked-by: Nirmoy Das <nirmoy.das@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

The existing code used the major version number of the DRM driver
instead of the device major number of the DRM subsystem for
validating access for a devices cgroup.

This meant that accesses allowed by the devices cgroup weren't
permitted and certain accesses denied by the devices cgroup were
permitted (if they matched the wrong major device number).
Signed-off-by: Lorenz Brun <lorenz@brun.one>
Fixes: 6b855f7b ("drm/amdkfd: Check against device cgroup")
Reviewed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

Pull dma-mapping fixes from Christoph Hellwig:
 "Fixes for the SEV atomic pool (Geert Uytterhoeven and David Rientjes)"

* tag 'dma-mapping-5.8-3' of git://git.infradead.org/users/hch/dma-mapping:
  dma-pool: decouple DMA_REMAP from DMA_COHERENT_POOL
  dma-pool: fix too large DMA pools on medium memory size systems

Better describe what these functions do.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Better describe what these functions do.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

To pick the changes from:

  b383a73f ("fs/ext4: Introduce DAX inode flag")

And silence this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/fs.h' differs from latest version at 'include/uapi/linux/fs.h'
  diff -u tools/include/uapi/linux/fs.h include/uapi/linux/fs.h

It causes various beautifiers for things like fspick, fsmount, etc (see
below) to get rebuilt, but this specific change doesn't make 'perf
trace' be capable of decoding anything new, as we still don't decode
what comes from ioctls, just its cmds.

Details about the update:

  $ cp include/uapi/linux/fs.h tools/include/uapi/linux/fs.h
  $ git diff
  diff --git a/tools/include/uapi/linux/fs.h b/tools/include/uapi/linux/fs.h
  index 379a612f8f1d..f44eb0a04afd 100644
  --- a/tools/include/uapi/linux/fs.h
  +++ b/tools/include/uapi/linux/fs.h
  @@ -262,6 +262,7 @@ struct fsxattr {
   #define FS_EA_INODE_FL                 0x00200000 /* Inode used for large EA */
   #define FS_EOFBLOCKS_FL                        0x00400000 /* Reserved for ext4 */
   #define FS_NOCOW_FL                    0x00800000 /* Do not cow file */
  +#define FS_DAX_FL                      0x02000000 /* Inode is DAX */
   #define FS_INLINE_DATA_FL              0x10000000 /* Reserved for ext4 */
   #define FS_PROJINHERIT_FL              0x20000000 /* Create with parents projid */
   #define FS_CASEFOLD_FL                 0x40000000 /* Folder is case insensitive */
  $ m
  make: Entering directory '/home/acme/git/perf/tools/perf'
    BUILD:   Doing 'make -j8' parallel build
    INSTALL  GTK UI
    CC       /tmp/build/perf/builtin-trace.o
    DESCEND  plugins
    CC       /tmp/build/perf/trace/beauty/fsmount.o
    CC       /tmp/build/perf/trace/beauty/fspick.o
    CC       /tmp/build/perf/trace/beauty/mount_flags.o
    CC       /tmp/build/perf/trace/beauty/move_mount.o
    CC       /tmp/build/perf/trace/beauty/renameat.o
    CC       /tmp/build/perf/trace/beauty/sync_file_range.o
    INSTALL  trace_plugins
    LD       /tmp/build/perf/trace/beauty/perf-in.o
    LD       /tmp/build/perf/perf-in.o
    LINK     /tmp/build/perf/perf
  <SNIP>

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To get the changes in:

  776f3950 ("vhost_vdpa: Support config interrupt in vdpa")

Silencing this perf build warning:

  Warning: Kernel ABI header at 'tools/include/uapi/linux/vhost.h' differs from latest version at 'include/uapi/linux/vhost.h'
  diff -u tools/include/uapi/linux/vhost.h include/uapi/linux/vhost.h

This automatically picks the new ioctl introduced in the above patch,
making tools such as 'perf trace' aware of them and possibly allowing to
use the strings in filters, etc:

  # perf trace -e ioctl --pid 7951
  <SNIP>
     0.178 ( 0.010 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
     0.194 ( 0.010 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
     0.209 ( 0.010 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
     0.224 (249.413 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.660 ( 0.011 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.675 ( 0.007 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.686 ( 0.007 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.697 ( 0.008 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.709 ( 0.007 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.720 ( 0.007 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.730 ( 0.007 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.740 ( 0.007 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.752 ( 0.007 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.762 ( 0.007 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.772 ( 0.007 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   249.782 (120.138 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   370.201 ( 0.039 ms): CPU 0/KVM/8023 ioctl(fd: 12, cmd: KVM_IRQ_LINE_STATUS, arg: 0x7f744f9e1420) = 0
   370.254 ( 0.052 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   370.575 ( 0.365 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   370.973 ( 0.028 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   371.015 ( 0.037 ms): CPU 0/KVM/8023 ioctl(fd: 14, cmd: KVM_RUN) = 0
   371.071 ( 0.009 ms): CPU 0/KVM/8023 ioctl(fd: 12, cmd: KVM_IRQ_LINE_STATUS, arg: 0x7f744f9e14b0) = 0
  <SNIP>
  #

Details about the update:

  $ diff -u tools/include/uapi/linux/vhost.h include/uapi/linux/vhost.h
  --- tools/include/uapi/linux/vhost.h	2020-04-16 13:19:12.056763843 -0300
  +++ include/uapi/linux/vhost.h	2020-06-17 10:04:20.532056428 -0300
  @@ -15,6 +15,8 @@
   #include <linux/types.h>
   #include <linux/ioctl.h>

  +#define VHOST_FILE_UNBIND -1
  +
   /* ioctls */

   #define VHOST_VIRTIO 0xAF
  @@ -140,4 +142,6 @@
   /* Get the max ring size. */
   #define VHOST_VDPA_GET_VRING_NUM	_IOR(VHOST_VIRTIO, 0x76, __u16)

  +/* Set event fd for config interrupt*/
  +#define VHOST_VDPA_SET_CONFIG_CALL	_IOW(VHOST_VIRTIO, 0x77, int)
   #endif
  $
  $ tools/perf/trace/beauty/vhost_virtio_ioctl.sh > before
  $ cp include/uapi/linux/vhost.h tools/include/uapi/linux/vhost.h
  $ tools/perf/trace/beauty/vhost_virtio_ioctl.sh > after
  $ diff -u before after
  --- before	2020-06-17 10:15:35.123275966 -0300
  +++ after	2020-06-17 10:15:51.812482117 -0300
  @@ -27,6 +27,7 @@
   	[0x72] = "VDPA_SET_STATUS",
   	[0x74] = "VDPA_SET_CONFIG",
   	[0x75] = "VDPA_SET_VRING_ENABLE",
  +	[0x77] = "VDPA_SET_CONFIG_CALL",
   };
   static const char *vhost_virtio_ioctl_read_cmds[] = {
   	[0x00] = "GET_FEATURES",
  $

This causes these parts to get rebuilt:

  CC       /tmp/build/perf/trace/beauty/ioctl.o
  INSTALL  trace_plugins
  LD       /tmp/build/perf/trace/beauty/perf-in.o
  LD       /tmp/build/perf/perf-in.o
  LINK     /tmp/build/perf/perf

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zhu Lingshan <lingshan.zhu@intel.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To pick up the changes in:

  7e5b3c26 ("x86/speculation: Add Special Register Buffer Data Sampling (SRBDS) mitigation")

Addressing these tools/perf build warnings:

  Warning: Kernel ABI header at 'tools/arch/x86/include/asm/msr-index.h' differs from latest version at 'arch/x86/include/asm/msr-index.h'
  diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
  Warning: Kernel ABI header at 'tools/arch/x86/include/asm/cpufeatures.h' differs from latest version at 'arch/x86/include/asm/cpufeatures.h'
  diff -u tools/arch/x86/include/asm/cpufeatures.h arch/x86/include/asm/cpufeatures.h

With this one will be able to use these new AMD MSRs in filters, by
name, e.g.:

  # perf trace -e msr:* --filter "msr==IA32_MCU_OPT_CTRL"
  ^C#

Using -v we can see how it sets up the tracepoint filters, converting
from the string in the filter to the numeric value:

  # perf trace -v -e msr:* --filter "msr==IA32_MCU_OPT_CTRL"
  Using CPUID GenuineIntel-6-8E-A
  0x123
  New filter for msr:read_msr: (msr==0x123) && (common_pid != 335 && common_pid != 30344)
  0x123
  New filter for msr:write_msr: (msr==0x123) && (common_pid != 335 && common_pid != 30344)
  0x123
  New filter for msr:rdpmc: (msr==0x123) && (common_pid != 335 && common_pid != 30344)
  mmap size 528384B
  ^C#

The updating process shows how this affects tooling in more detail:

  $ diff -u tools/arch/x86/include/asm/msr-index.h arch/x86/include/asm/msr-index.h
  --- tools/arch/x86/include/asm/msr-index.h	2020-06-03 10:36:09.959910238 -0300
  +++ arch/x86/include/asm/msr-index.h	2020-06-17 10:04:20.235052901 -0300
  @@ -128,6 +128,10 @@
   #define TSX_CTRL_RTM_DISABLE		BIT(0)	/* Disable RTM feature */
   #define TSX_CTRL_CPUID_CLEAR		BIT(1)	/* Disable TSX enumeration */

  +/* SRBDS support */
  +#define MSR_IA32_MCU_OPT_CTRL		0x00000123
  +#define RNGDS_MITG_DIS			BIT(0)
  +
   #define MSR_IA32_SYSENTER_CS		0x00000174
   #define MSR_IA32_SYSENTER_ESP		0x00000175
   #define MSR_IA32_SYSENTER_EIP		0x00000176
  $ set -o vi
  $ tools/perf/trace/beauty/tracepoints/x86_msr.sh > before
  $ cp arch/x86/include/asm/msr-index.h tools/arch/x86/include/asm/msr-index.h
  $ tools/perf/trace/beauty/tracepoints/x86_msr.sh > after
  $ diff -u before after
  --- before	2020-06-17 10:05:49.653114752 -0300
  +++ after	2020-06-17 10:06:01.777258731 -0300
  @@ -51,6 +51,7 @@
   	[0x0000011e] = "IA32_BBL_CR_CTL3",
   	[0x00000120] = "IDT_MCR_CTRL",
   	[0x00000122] = "IA32_TSX_CTRL",
  +	[0x00000123] = "IA32_MCU_OPT_CTRL",
   	[0x00000140] = "MISC_FEATURES_ENABLES",
   	[0x00000174] = "IA32_SYSENTER_CS",
   	[0x00000175] = "IA32_SYSENTER_ESP",
  $

The related change to cpu-features.h affects this:

  CC       /tmp/build/perf/bench/mem-memcpy-x86-64-asm.o
  CC       /tmp/build/perf/bench/mem-memset-x86-64-asm.o

This shouldn't be affecting that 'perf bench' entry:

  $ find tools/perf/ -type f | xargs grep SRBDS
  $

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Gross <mgross@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

To get some newer headers that got out of sync with the copies in tools/
so that we can try to have the tools/perf/ build clean for v5.8 with
fewer pull requests.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Fixes segmentation fault when trying to interpret zstd-compressed data
with perf script:

```
  $ perf record -z ls
  ...
  [ perf record: Captured and wrote 0,010 MB perf.data, compressed (original 0,001 MB, ratio is 2,190) ]
  $ memcheck perf script
  ...
  ==67911== Invalid read of size 4
  ==67911==    at 0x5568188: ZSTD_decompressStream (in /usr/lib/libzstd.so.1.4.5)
  ==67911==    by 0x6E726B: zstd_decompress_stream (zstd.c:100)
  ==67911==    by 0x65729C: perf_session__process_compressed_event (session.c:72)
  ==67911==    by 0x6598E8: perf_session__process_user_event (session.c:1583)
  ==67911==    by 0x65BA59: reader__process_events (session.c:2177)
  ==67911==    by 0x65BA59: __perf_session__process_events (session.c:2234)
  ==67911==    by 0x65BA59: perf_session__process_events (session.c:2267)
  ==67911==    by 0x5A7397: __cmd_script (builtin-script.c:2447)
  ==67911==    by 0x5A7397: cmd_script (builtin-script.c:3840)
  ==67911==    by 0x5FE9D2: run_builtin (perf.c:312)
  ==67911==    by 0x711627: handle_internal_command (perf.c:364)
  ==67911==    by 0x711627: run_argv (perf.c:408)
  ==67911==    by 0x711627: main (perf.c:538)
  ==67911==  Address 0x71d8 is not stack'd, malloc'd or (recently) free'd
```
Signed-off-by: Milian Wolff <milian.wolff@kdab.com>
Acked-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
LPU-Reference: 20200612230333.72140-1-milian.wolff@kdab.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Mostly for historical reasons, q->blk_trace is assigned through xchg()
and cmpxchg() atomic operations. Although this is correct, sparse
complains about this because it violates rcu annotations since commit
c780e86d ("blktrace: Protect q->blk_trace with RCU") which started
to use rcu for accessing q->blk_trace. Furthermore there's no real need
for atomic operations anymore since all changes to q->blk_trace happen
under q->blk_trace_mutex and since it also makes more sense to check if
q->blk_trace is set with the mutex held earlier.

So let's just replace xchg() with rcu_replace_pointer() and cmpxchg()
with explicit check and rcu_assign_pointer(). This makes the code more
efficient and sparse happy.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

We use one blktrace per request_queue, that means one per the entire
disk.  So we cannot run one blktrace on say /dev/vda and then /dev/vda1,
or just two calls on /dev/vda.

We check for concurrent setup only at the very end of the blktrace setup though.

If we try to run two concurrent blktraces on the same block device the
second one will fail, and the first one seems to go on. However when
one tries to kill the first one one will see things like this:

The kernel will show these:

```
debugfs: File 'dropped' in directory 'nvme1n1' already present!
debugfs: File 'msg' in directory 'nvme1n1' already present!
debugfs: File 'trace0' in directory 'nvme1n1' already present!
``

And userspace just sees this error message for the second call:

```
blktrace /dev/nvme1n1
BLKTRACESETUP(2) /dev/nvme1n1 failed: 5/Input/output error
```

The first userspace process #1 will also claim that the files
were taken underneath their nose as well. The files are taken
away form the first process given that when the second blktrace
fails, it will follow up with a BLKTRACESTOP and BLKTRACETEARDOWN.
This means that even if go-happy process #1 is waiting for blktrace
data, we *have* been asked to take teardown the blktrace.

This can easily be reproduced with break-blktrace [0] run_0005.sh test.

Just break out early if we know we're already going to fail, this will
prevent trying to create the files all over again, which we know still
exist.

[0] https://github.com/mcgrof/break-blktraceSigned-off-by: Luis Chamberlain <mcgrof@kernel.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Unfortunately, most versions of clang that support BTI are capable of
miscompiling the kernel when converting a switch statement into a jump
table. As an example, attempting to spawn a KVM guest results in a panic:

[   56.253312] Kernel panic - not syncing: bad mode
[   56.253834] CPU: 0 PID: 279 Comm: lkvm Not tainted 5.8.0-rc1 #2
[   56.254225] Hardware name: QEMU QEMU Virtual Machine, BIOS 0.0.0 02/06/2015
[   56.254712] Call trace:
[   56.254952]  dump_backtrace+0x0/0x1d4
[   56.255305]  show_stack+0x1c/0x28
[   56.255647]  dump_stack+0xc4/0x128
[   56.255905]  panic+0x16c/0x35c
[   56.256146]  bad_el0_sync+0x0/0x58
[   56.256403]  el1_sync_handler+0xb4/0xe0
[   56.256674]  el1_sync+0x7c/0x100
[   56.256928]  kvm_vm_ioctl_check_extension_generic+0x74/0x98
[   56.257286]  __arm64_sys_ioctl+0x94/0xcc
[   56.257569]  el0_svc_common+0x9c/0x150
[   56.257836]  do_el0_svc+0x84/0x90
[   56.258083]  el0_sync_handler+0xf8/0x298
[   56.258361]  el0_sync+0x158/0x180

This is because the switch in kvm_vm_ioctl_check_extension_generic()
is executed as an indirect branch to tail-call through a jump table:

ffff800010032dc8:       3869694c        ldrb    w12, [x10, x9]
ffff800010032dcc:       8b0c096b        add     x11, x11, x12, lsl #2
ffff800010032dd0:       d61f0160        br      x11

However, where the target case uses the stack, the landing pad is elided
due to the presence of a paciasp instruction:

ffff800010032e14:       d503233f        paciasp
ffff800010032e18:       a9bf7bfd        stp     x29, x30, [sp, #-16]!
ffff800010032e1c:       910003fd        mov     x29, sp
ffff800010032e20:       aa0803e0        mov     x0, x8
ffff800010032e24:       940017c0        bl      ffff800010038d24 <kvm_vm_ioctl_check_extension>
ffff800010032e28:       93407c00        sxtw    x0, w0
ffff800010032e2c:       a8c17bfd        ldp     x29, x30, [sp], #16
ffff800010032e30:       d50323bf        autiasp
ffff800010032e34:       d65f03c0        ret

Unfortunately, this results in a fatal exception because paciasp is
compatible only with branch-and-link (call) instructions and not simple
indirect branches.

A fix is being merged into Clang 10.0.1 so that a 'bti j' instruction is
emitted as an explicit landing pad in this situation. Make in-kernel
BTI depend on that compiler version when building with clang.

Cc: Tom Stellard <tstellar@redhat.com>
Cc: Daniel Kiss <daniel.kiss@arm.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Acked-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Acked-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lore.kernel.org/r/20200615105524.GA2694@willie-the-truck
Link: https://lore.kernel.org/r/20200616183630.2445-1-will@kernel.orgSigned-off-by: Will Deacon <will@kernel.org>

Add flex_array_size() helper for the calculation of the size, in bytes,
of a flexible array member contained within an enclosing structure.

Example of usage:

struct something {
	size_t count;
	struct foo items[];
};

struct something *instance;

instance = kmalloc(struct_size(instance, items, count), GFP_KERNEL);
instance->count = count;
memcpy(instance->items, src, flex_array_size(instance, items, instance->count));

The helper returns SIZE_MAX on overflow instead of wrapping around.

Additionally replaces parameter "n" with "count" in struct_size() helper
for greater clarity and unification.
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20200609012233.GA3371@embeddedorSigned-off-by: Kees Cook <keescook@chromium.org>