Add a KUnit test for the kernel doubly linked list implementation in
include/linux/list.h

Each test case (list_test_x) is focused on testing the behaviour of the
list function/macro 'x'. None of the tests pass invalid lists to these
macros, and so should behave identically with DEBUG_LIST enabled and
disabled.

Note that, at present, it only tests the list_ types (not the
singly-linked hlist_), and does not yet test all of the
list_for_each_entry* macros (and some related things like
list_prepare_entry).

Ignoring checkpatch.pl spurious errors related to its handling of for_each
and other list macros. checkpatch.pl expects anything with for_each in its
name to be a loop and expects that the open brace is placed on the same
line as for a for loop. In this case, test case naming scheme includes
name of the macro it is testing, which results in the spurious errors.
Commit message updated by Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: NDavid Gow <davidgow@google.com>
Reviewed-by: NBrendan Higgins <brendanhiggins@google.com>
Tested-by: NBrendan Higgins <brendanhiggins@google.com>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

KUnit tests for decoding extended 64 bit timestamps that verify the
seconds part of [a/c/m] timestamps in ext4 inode structs are decoded
correctly.

Test data is derived from the table in the Inode Timestamps section of
Documentation/filesystems/ext4/inodes.rst.

KUnit tests run during boot and output the results to the debug log
in TAP format (http://testanything.org/). Only useful for kernel devs
running KUnit test harness and are not for inclusion into a production
build.
Signed-off-by: NIurii Zaikin <yzaikin@google.com>
Reviewed-by: NTheodore Ts'o <tytso@mit.edu>
Reviewed-by: NBrendan Higgins <brendanhiggins@google.com>
Tested-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NShuah Khan <skhan@linuxfoundation.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

kunit wrapper script ('kunit.py') receives a sub-command (only 'run' for
now) as its argument.  If no sub-command is given, it prints help
message and just quit.  However, an example command in the kunit
documentation for a verification of kunit is missing the sub-command.
This commit fixes the example.
Signed-off-by: NSeongJae Park <sj38.park@gmail.com>
Reviewed-by: NBrendan Higgins <brendanhiggins@google.com>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Running kunit with '--build_dir' option gives following error message:

```
$ ./tools/testing/kunit/kunit.py run --build_dir ../linux.out.kunit/
[00:57:24] Building KUnit Kernel ...
[00:57:29] Starting KUnit Kernel ...
Traceback (most recent call last):
  File "./tools/testing/kunit/kunit.py", line 136, in <module>
    main(sys.argv[1:])
  File "./tools/testing/kunit/kunit.py", line 129, in main
    result = run_tests(linux, request)
  File "./tools/testing/kunit/kunit.py", line 68, in run_tests
    test_result = kunit_parser.parse_run_tests(kunit_output)
  File "/home/sjpark/linux/tools/testing/kunit/kunit_parser.py", line
283, in parse_run_tests
    test_result =
parse_test_result(list(isolate_kunit_output(kernel_output)))
  File "/home/sjpark/linux/tools/testing/kunit/kunit_parser.py", line
54, in isolate_kunit_output
    for line in kernel_output:
  File "/home/sjpark/linux/tools/testing/kunit/kunit_kernel.py", line
145, in run_kernel
    process = self._ops.linux_bin(args, timeout, build_dir)
  File "/home/sjpark/linux/tools/testing/kunit/kunit_kernel.py", line
69, in linux_bin
    stderr=subprocess.PIPE)
  File "/usr/lib/python3.5/subprocess.py", line 947, in __init__
    restore_signals, start_new_session)
  File "/usr/lib/python3.5/subprocess.py", line 1551, in _execute_child
    raise child_exception_type(errno_num, err_msg)
FileNotFoundError: [Errno 2] No such file or directory: './linux'
```

This error occurs because the '--build_dir' option value is not passed
to the 'run_kernel()' function.  Consequently, the function assumes
the kernel image that built for the tests, which is under the
'--build_dir' directory, is in kernel source directory and finally raises
the 'FileNotFoundError'.

This commit fixes the problem by properly passing the '--build_dir'
option value to the 'run_kernel()'.
Signed-off-by: NSeongJae Park <sj38.park@gmail.com>
Reviewed-by: NBrendan Higgins <brendanhiggins@google.com>
Tested-by: NBrendan Higgins <brendanhiggins@google.com>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Previously KUnit assumed that printk would always be present, which is
not a valid assumption to make. Fix that by removing call to
vprintk_emit, and calling printk directly.

This fixes a build error[1] reported by Randy.

For context this change comes after much discussion. My first stab[2] at
this was just to make the KUnit logging code compile out; however, it
was agreed that if we were going to use vprintk_emit, then vprintk_emit
should provide a no-op stub, which lead to my second attempt[3]. In
response to me trying to stub out vprintk_emit, Sergey Senozhatsky
suggested a way for me to remove our usage of vprintk_emit, which led to
my third attempt at solving this[4].

In my third version of this patch[4], I completely removed vprintk_emit,
as suggested by Sergey; however, there was a bit of debate over whether
Sergey's solution was the best. The debate arose due to Sergey's version
resulting in a checkpatch warning, which resulted in a debate over
correct printk usage. Joe Perches offered an alternative fix which was
somewhat less far reaching than what Sergey had suggested and
importantly relied on continuing to use %pV. Much of the debated
centered around whether %pV should be widely used, and whether Sergey's
version would result in object size bloat. Ultimately, we decided to go
with Sergey's version.
Reported-by: NRandy Dunlap <rdunlap@infradead.org>
Link[1]: https://lore.kernel.org/linux-kselftest/c7229254-0d90-d90e-f3df-5b6d6fc0b51f@infradead.org/
Link[2]: https://lore.kernel.org/linux-kselftest/20190827174932.44177-1-brendanhiggins@google.com/
Link[3]: https://lore.kernel.org/linux-kselftest/20190827234835.234473-1-brendanhiggins@google.com/
Link[4]: https://lore.kernel.org/linux-kselftest/20190828093143.163302-1-brendanhiggins@google.com/
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Cc: Joe Perches <joe@perches.com>
Cc: Tim.Bird@sony.com
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Reviewed-by: NPetr Mladek <pmladek@suse.com>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add entry for the new proc sysctl KUnit test to the PROC SYSCTL section,
and add Iurii as a maintainer.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Cc: Iurii Zaikin <yzaikin@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Acked-by: NLuis Chamberlain <mcgrof@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

KUnit tests for initialized data behavior of proc_dointvec that is
explicitly checked in the code. Includes basic parsing tests including
int min/max overflow.
Signed-off-by: NIurii Zaikin <yzaikin@google.com>
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Acked-by: NLuis Chamberlain <mcgrof@kernel.org>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add myself as maintainer of KUnit, the Linux kernel's unit testing
framework.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add documentation for KUnit, the Linux kernel unit testing framework.
- Add intro and usage guide for KUnit
- Add API reference
Signed-off-by: NFelix Guo <felixguoxiuping@gmail.com>
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add defconfig for UML and a fragment that can be used to configure other
architectures for building KUnit tests. Add option to kunit_tool to use
a defconfig to create the kunitconfig.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

The ultimate goal is to create minimal isolated test binaries; in the
meantime we are using UML to provide the infrastructure to run tests, so
define an abstract way to configure and run tests that allow us to
change the context in which tests are built without affecting the user.
This also makes pretty and dynamic error reporting, and a lot of other
nice features easier.

kunit_config.py:
  - parse .config and Kconfig files.

kunit_kernel.py: provides helper functions to:
  - configure the kernel using kunitconfig.
  - build the kernel with the appropriate configuration.
  - provide function to invoke the kernel and stream the output back.

kunit_parser.py: parses raw logs returned out by kunit_kernel and
displays them in a user friendly way.

test_data/*: samples of test data for testing kunit.py, kunit_config.py,
etc.
Signed-off-by: NFelix Guo <felixguoxiuping@gmail.com>
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add unit tests for KUnit managed resources. KUnit managed resources
(struct kunit_resource) are resources that are automatically cleaned up
at the end of a KUnit test, similar to the concept of devm_* managed
resources.
Signed-off-by: NAvinash Kondareddy <akndr41@gmail.com>
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add support for assertions which are like expectations except the test
terminates if the assertion is not satisfied.

The idea with assertions is that you use them to state all the
preconditions for your test. Logically speaking, these are the premises
of the test case, so if a premise isn't true, there is no point in
continuing the test case because there are no conclusions that can be
drawn without the premises. Whereas, the expectation is the thing you
are trying to prove. It is not used universally in x-unit style test
frameworks, but I really like it as a convention.  You could still
express the idea of a premise using the above idiom, but I think
KUNIT_ASSERT_* states the intended idea perfectly.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add KUnit tests for the KUnit test abort mechanism (see preceding
commit). Add tests both for general try catch mechanism as well as
non-architecture specific mechanism.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add support for aborting/bailing out of test cases, which is needed for
implementing assertions.

An assertion is like an expectation, but bails out of the test case
early if the assertion is not met. The idea with assertions is that you
use them to state all the preconditions for your test. Logically
speaking, these are the premises of the test case, so if a premise isn't
true, there is no point in continuing the test case because there are no
conclusions that can be drawn without the premises. Whereas, the
expectation is the thing you are trying to prove.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Fix the following warning seen on GCC 7.3:
  kunit/test-test.o: warning: objtool: kunit_test_unsuccessful_try() falls through to next function kunit_test_catch()

kunit_try_catch_throw is a function added in the following patch in this
series; it allows KUnit, a unit testing framework for the kernel, to
bail out of a broken test. As a consequence, it is a new __noreturn
function that objtool thinks is broken (as seen above). So fix this
warning by adding kunit_try_catch_throw to objtool's noreturn list.
Reported-by: Nkbuild test robot <lkp@intel.com>
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Acked-by: NJosh Poimboeuf <jpoimboe@redhat.com>
Link: https://www.spinics.net/lists/linux-kbuild/msg21708.html
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add a test for string stream along with a simpler example.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

KUnit is a new unit testing framework for the kernel and when used is
built into the kernel as a part of it. Add KUnit to the lib Kconfig and
Makefile to allow it to be actually built.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Kees Cook <keescook@chromium.org>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add support for expectations, which allow properties to be specified and
then verified in tests.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add `struct kunit_assert` and friends which provide a structured way to
capture data from an expectation or an assertion (introduced later in
the series) so that it may be printed out in the event of a failure.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

A number of test features need to do pretty complicated string printing
where it may not be possible to rely on a single preallocated string
with parameters.

So provide a library for constructing the string as you go similar to
C++'s std::string. string_stream is really just a string builder,
nothing more.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <swboyd@chromium.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Create a common API for test managed resources like memory and test
objects. A lot of times a test will want to set up infrastructure to be
used in test cases; this could be anything from just wanting to allocate
some memory to setting up a driver stack; this defines facilities for
creating "test resources" which are managed by the test infrastructure
and are automatically cleaned up at the conclusion of the test.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Add core facilities for defining unit tests; this provides a common way
to define test cases, functions that execute code which is under test
and determine whether the code under test behaves as expected; this also
provides a way to group together related test cases in test suites (here
we call them test_modules).

Just define test cases and how to execute them for now; setting
expectations on code will be defined later.
Signed-off-by: NBrendan Higgins <brendanhiggins@google.com>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: NLogan Gunthorpe <logang@deltatee.com>
Reviewed-by: NLuis Chamberlain <mcgrof@kernel.org>
Reviewed-by: NStephen Boyd <sboyd@kernel.org>
Signed-off-by: NShuah Khan <skhan@linuxfoundation.org>

Pull btrfs fixes from David Sterba:
 "A bunch of fixes that accumulated in recent weeks, mostly material for
  stable.

  Summary:

   - fix for regression from 5.3 that prevents to use balance convert
     with single profile

   - qgroup fixes: rescan race, accounting leak with multiple writers,
     potential leak after io failure recovery

   - fix for use after free in relocation (reported by KASAN)

   - other error handling fixups"

* tag 'for-5.4-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  btrfs: qgroup: Fix reserved data space leak if we have multiple reserve calls
  btrfs: qgroup: Fix the wrong target io_tree when freeing reserved data space
  btrfs: Fix a regression which we can't convert to SINGLE profile
  btrfs: relocation: fix use-after-free on dead relocation roots
  Btrfs: fix race setting up and completing qgroup rescan workers
  Btrfs: fix missing error return if writeback for extent buffer never started
  btrfs: adjust dirty_metadata_bytes after writeback failure of extent buffer
  Btrfs: fix selftests failure due to uninitialized i_mode in test inodes

Pull csky updates from Guo Ren:
 "This round of csky subsystem just some fixups:

   - Fix mb() synchronization problem

   - Fix dma_alloc_coherent with PAGE_SO attribute

   - Fix cache_op failed when cross memory ZONEs

   - Optimize arch_sync_dma_for_cpu/device with dma_inv_range

   - Fix ioremap function losing

   - Fix arch_get_unmapped_area() implementation

   - Fix defer cache flush for 610

   - Support kernel non-aligned access

   - Fix 610 vipt cache flush mechanism

   - Fix add zero_fp fixup perf backtrace panic

   - Move static keyword to the front of declaration

   - Fix csky_pmu.max_period assignment

   - Use generic free_initrd_mem()

   - entry: Remove unneeded need_resched() loop"

* tag 'csky-for-linus-5.4-rc1' of git://github.com/c-sky/csky-linux:
  csky: Move static keyword to the front of declaration
  csky: entry: Remove unneeded need_resched() loop
  csky: Fixup csky_pmu.max_period assignment
  csky: Fixup add zero_fp fixup perf backtrace panic
  csky: Use generic free_initrd_mem()
  csky: Fixup 610 vipt cache flush mechanism
  csky: Support kernel non-aligned access
  csky: Fixup defer cache flush for 610
  csky: Fixup arch_get_unmapped_area() implementation
  csky: Fixup ioremap function losing
  csky: Optimize arch_sync_dma_for_cpu/device with dma_inv_range
  csky/dma: Fixup cache_op failed when cross memory ZONEs
  csky: Fixup dma_alloc_coherent with PAGE_SO attribute
  csky: Fixup mb() synchronization problem

Pull ARM SoC fixes from Olof Johansson:
 "A few fixes that have trickled in through the merge window:

   - Video fixes for OMAP due to panel-dpi driver removal

   - Clock fixes for OMAP that broke no-idle quirks + nfsroot on DRA7

   - Fixing arch version on ASpeed ast2500

   - Two fixes for reset handling on ARM SCMI"

* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
  ARM: aspeed: ast2500 is ARMv6K
  reset: reset-scmi: add missing handle initialisation
  firmware: arm_scmi: reset: fix reset_state assignment in scmi_domain_reset
  bus: ti-sysc: Remove unpaired sysc_clkdm_deny_idle()
  ARM: dts: logicpd-som-lv: Fix i2c2 and i2c3 Pin mux
  ARM: dts: am3517-evm: Fix missing video
  ARM: dts: logicpd-torpedo-baseboard: Fix missing video
  ARM: omap2plus_defconfig: Fix missing video
  bus: ti-sysc: Fix handling of invalid clocks
  bus: ti-sysc: Fix clock handling for no-idle quirks

Pull tracing fixes from Steven Rostedt:
 "A few more tracing fixes:

   - Fix a buffer overflow by checking nr_args correctly in probes

   - Fix a warning that is reported by clang

   - Fix a possible memory leak in error path of filter processing

   - Fix the selftest that checks for failures, but wasn't failing

   - Minor clean up on call site output of a memory trace event"

* tag 'trace-v5.4-3' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  selftests/ftrace: Fix same probe error test
  mm, tracing: Print symbol name for call_site in trace events
  tracing: Have error path in predicate_parse() free its allocated memory
  tracing: Fix clang -Wint-in-bool-context warnings in IF_ASSIGN macro
  tracing/probe: Fix to check the difference of nr_args before adding probe

Pull more MMC updates from Ulf Hansson:
 "A couple more updates/fixes for MMC:

   - sdhci-pci: Add Genesys Logic GL975x support

   - sdhci-tegra: Recover loss in throughput for DMA

   - sdhci-of-esdhc: Fix DMA bug"

* tag 'mmc-v5.4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc:
  mmc: host: sdhci-pci: Add Genesys Logic GL975x support
  mmc: tegra: Implement ->set_dma_mask()
  mmc: sdhci: Let drivers define their DMA mask
  mmc: sdhci-of-esdhc: set DMA snooping based on DMA coherence
  mmc: sdhci: improve ADMA error reporting

Move the static keyword to the front of declaration of
csky_pmu_of_device_ids, and resolve the following compiler
warning that can be seen when building with warnings
enabled (W=1):

arch/csky/kernel/perf_event.c:1340:1: warning:
  ‘static’ is not at beginning of declaration [-Wold-style-declaration]
Signed-off-by: NKrzysztof Wilczynski <kw@linux.com>
Signed-off-by: NGuo Ren <guoren@kernel.org>

Since the enabling and disabling of IRQs within preempt_schedule_irq()
is contained in a need_resched() loop, we don't need the outer arch
code loop.
Signed-off-by: NValentin Schneider <valentin.schneider@arm.com>
Signed-off-by: NGuo Ren <guoren@kernel.org>

Pull Documentation/process update from Greg KH:
 "Here are two small Documentation/process/embargoed-hardware-issues.rst
  file updates that missed my previous char/misc pull request.

  The first one adds an Intel representative for the process, and the
  second one cleans up the text a bit more when it comes to how the
  disclosure rules work, as it was a bit confusing to some companies"

* tag 'char-misc-5.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc:
  Documentation/process: Clarify disclosure rules
  Documentation/process: Volunteer as the ambassador for Intel

Pull more vfs updates from Al Viro:
 "A couple of misc patches"

* 'work.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  afs dynroot: switch to simple_dir_operations
  fs/handle.c - fix up kerneldoc

Pull more cifs updates from Steve French:
 "Fixes from the recent SMB3 Test events and Storage Developer
  Conference (held the last two weeks).

  Here are nine smb3 patches including an important patch for debugging
  traces with wireshark, with three patches marked for stable.

  Additional fixes from last week to better handle some newly discovered
  reparse points, and a fix the create/mkdir path for setting the mode
  more atomically (in SMB3 Create security descriptor context), and one
  for path name processing are still being tested so are not included
  here"

* tag '5.4-rc-smb3-fixes' of git://git.samba.org/sfrench/cifs-2.6:
  CIFS: Fix oplock handling for SMB 2.1+ protocols
  smb3: missing ACL related flags
  smb3: pass mode bits into create calls
  smb3: Add missing reparse tags
  CIFS: fix max ea value size
  fs/cifs/sess.c: Remove set but not used variable 'capabilities'
  fs/cifs/smb2pdu.c: Make SMB2_notify_init static
  smb3: fix leak in "open on server" perf counter
  smb3: allow decryption keys to be dumped by admin for debugging

The csky_pmu.max_period has type u64, and BIT() can only return
32 bits unsigned long on C-SKY. The initialization for max_period
will be incorrect when count_width is bigger than 32.

Use BIT_ULL()
Signed-off-by: NMao Han <han_mao@c-sky.com>
Signed-off-by: NGuo Ren <ren_guo@c-sky.com>

We need set fp zero to let backtrace know the end. The patch fixup perf
callchain panic problem, because backtrace didn't know what is the end
of fp.
Signed-off-by: NGuo Ren <ren_guo@c-sky.com>
Reported-by: NMao Han <han_mao@c-sky.com>

The csky implementation of free_initrd_mem() is an open-coded version of
free_reserved_area() without poisoning.

Remove it and make csky use the generic version of free_initrd_mem().
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NGuo Ren <guoren@kernel.org>

Merge active entropy generation updates.

This is admittedly partly "for discussion".  We need to have a way
forward for the boot time deadlocks where user space ends up waiting for
more entropy, but no entropy is forthcoming because the system is
entirely idle just waiting for something to happen.

While this was triggered by what is arguably a user space bug with
GDM/gnome-session asking for secure randomness during early boot, when
they didn't even need any such truly secure thing, the issue ends up
being that our "getrandom()" interface is prone to that kind of
confusion, because people don't think very hard about whether they want
to block for sufficient amounts of entropy.

The approach here-in is to decide to not just passively wait for entropy
to happen, but to start actively collecting it if it is missing.  This
is not necessarily always possible, but if the architecture has a CPU
cycle counter, there is a fair amount of noise in the exact timings of
reasonably complex loads.

We may end up tweaking the load and the entropy estimates, but this
should be at least a reasonable starting point.

As part of this, we also revert the revert of the ext4 IO pattern
improvement that ended up triggering the reported lack of external
entropy.

* getrandom() active entropy waiting:
  Revert "Revert "ext4: make __ext4_get_inode_loc plug""
  random: try to actively add entropy rather than passively wait for it

This reverts commit 72dbcf72.

Instead of waiting forever for entropy that may just not happen, we now
try to actively generate entropy when required, and are thus hopefully
avoiding the problem that caused the nice ext4 IO pattern fix to be
reverted.

So revert the revert.

Cc: Ahmed S. Darwish <darwish.07@gmail.com>
Cc: Ted Ts'o <tytso@mit.edu>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Alexander E. Patrakov <patrakov@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For 5.3 we had to revert a nice ext4 IO pattern improvement, because it
caused a bootup regression due to lack of entropy at bootup together
with arguably broken user space that was asking for secure random
numbers when it really didn't need to.

See commit 72dbcf72 (Revert "ext4: make __ext4_get_inode_loc plug").

This aims to solve the issue by actively generating entropy noise using
the CPU cycle counter when waiting for the random number generator to
initialize.  This only works when you have a high-frequency time stamp
counter available, but that's the case on all modern x86 CPU's, and on
most other modern CPU's too.

What we do is to generate jitter entropy from the CPU cycle counter
under a somewhat complex load: calling the scheduler while also
guaranteeing a certain amount of timing noise by also triggering a
timer.

I'm sure we can tweak this, and that people will want to look at other
alternatives, but there's been a number of papers written on jitter
entropy, and this should really be fairly conservative by crediting one
bit of entropy for every timer-induced jump in the cycle counter.  Not
because the timer itself would be all that unpredictable, but because
the interaction between the timer and the loop is going to be.

Even if (and perhaps particularly if) the timer actually happens on
another CPU, the cacheline interaction between the loop that reads the
cycle counter and the timer itself firing is going to add perturbations
to the cycle counter values that get mixed into the entropy pool.

As Thomas pointed out, with a modern out-of-order CPU, even quite simple
loops show a fair amount of hard-to-predict timing variability even in
the absense of external interrupts.  But this tries to take that further
by actually having a fairly complex interaction.

This is not going to solve the entropy issue for architectures that have
no CPU cycle counter, but it's not clear how (and if) that is solvable,
and the hardware in question is largely starting to be irrelevant.  And
by doing this we can at least avoid some of the even more contentious
approaches (like making the entropy waiting time out in order to avoid
the possibly unbounded waiting).

Cc: Ahmed Darwish <darwish.07@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Nicholas Mc Guire <hofrat@opentech.at>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Willy Tarreau <w@1wt.eu>
Cc: Alexander E. Patrakov <patrakov@gmail.com>
Cc: Lennart Poettering <mzxreary@0pointer.de>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>