Pull driver core fixes from Greg KH:
 "Here are some driver core fixes, a kobject fix, and a documentation
  update for 6.8-rc5. In detail these changes are:

   - devlink fixes for reported issues with 6.8-rc1

   - topology scheduling regression fix that has been reported by many

   - kobject loosening of checks change in -rc1 is now reverted as some
     codepaths seemed to need the checks

   - documentation update for the CVE process. Has been reviewed by
     many, the last minute change to the document was to bring the .rst
     format back into the the new style rules, the contents did not
     change.

  All of these, except for the documentation update, have been in
  linux-next for over a week. The documentation update has been reviewed
  for weeks by a group of developers, and in public for a week and the
  wording has stabilized for now. If future changes are needed, we can
  do so before 6.8-final is out (or anytime after that)"

* tag 'driver-core-6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core:
  Documentation: Document the Linux Kernel CVE process
  Revert "kobject: Remove redundant checks for whether ktype is NULL"
  driver core: fw_devlink: Improve logs for cycle detection
  driver core: fw_devlink: Improve detection of overlapping cycles
  driver core: Fix device_link_flag_is_sync_state_only()
  topology: Set capacity_freq_ref in all cases

Pull tracing fixes from Steven Rostedt:

 - Fix the #ifndef that didn't have the 'CONFIG_' prefix on
   HAVE_DYNAMIC_FTRACE_WITH_REGS

   The fix to have dynamic trampolines work with x86 broke arm64 as the
   config used in the #ifdef was HAVE_DYNAMIC_FTRACE_WITH_REGS and not
   CONFIG_HAVE_DYNAMIC_FTRACE_WITH_REGS which removed the fix that the
   previous fix was to fix.

 - Fix tracing_on state

   The code to test if "tracing_on" is set incorrectly used
   ring_buffer_record_is_on() which returns false if the ring buffer
   isn't able to be written to.

   But the ring buffer disable has several bits that disable it. One is
   internal disabling which is used for resizing and other modifications
   of the ring buffer. But the "tracing_on" user space visible flag
   should only report if tracing is actually on and not internally
   disabled, as this can cause confusion as writing "1" when it is
   disabled will not enable it.

   Instead use ring_buffer_record_is_set_on() which shows the user space
   visible settings.

 - Fix a false positive kmemleak on saved cmdlines

   Now that the saved_cmdlines structure is allocated via alloc_page()
   and not via kmalloc() it has become invisible to kmemleak. The
   allocation done to one of its pointers was flagged as a dangling
   allocation leak. Make kmemleak aware of this allocation and free.

 - Fix synthetic event dynamic strings

   An update that cleaned up the synthetic event code removed the return
   value of trace_string(), and had it return zero instead of the
   length, causing dynamic strings in the synthetic event to always have
   zero size.

 - Clean up documentation and header files for seq_buf

* tag 'trace-v6.8-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  seq_buf: Fix kernel documentation
  seq_buf: Don't use "proxy" headers
  tracing/synthetic: Fix trace_string() return value
  tracing: Inform kmemleak of saved_cmdlines allocation
  tracing: Use ring_buffer_record_is_set_on() in tracer_tracing_is_on()
  tracing: Fix HAVE_DYNAMIC_FTRACE_WITH_REGS ifdef

There are plenty of issues with the kernel documentation here:
  - misspelled word "sequence"
  - different style of returned value descriptions
  - missed Return sections
  - unaligned style of ASCII / NUL-terminated / etc
  - wrong function references

Fix all these.

Link: https://lkml.kernel.org/r/20240215152506.598340-1-andriy.shevchenko@linux.intel.com

Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Update header inclusions to follow IWYU (Include What You Use)
principle.

Link: https://lkml.kernel.org/r/20240215142255.400264-1-andriy.shevchenko@linux.intel.com

Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

Pull KUnit fix from Shuah Khan:
 "One important fix to unregister kunit_bus when KUnit module is
  unloaded.

  Not doing so causes an error when KUnit module tries to re-register
  the bus when it gets reloaded"

* tag 'linux_kselftest-kunit-fixes-6.8-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  kunit: device: Unregister the kunit_bus on shutdown

This reverts commit 1b28cb81dab7c1eedc6034206f4e8d644046ad31.

It is reported to cause problems, so revert it for now until the root
cause can be found.

Reported-by: kernel test robot <oliver.sang@intel.com>
Fixes: 1b28cb81dab7 ("kobject: Remove redundant checks for whether ktype is NULL")
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Closes: https://lore.kernel.org/oe-lkp/202402071403.e302e33a-oliver.sang@intel.com
Link: https://lore.kernel.org/r/2024020849-consensus-length-6264@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

If KUnit is built as a module, and it's unloaded, the kunit_bus is not
unregistered. This causes an error if it's then re-loaded later, as we
try to re-register the bus.

Unregister the bus and root_device on shutdown, if it looks valid.

In addition, be more specific about the value of kunit_bus_device. It
is:
- a valid struct device* if the kunit_bus initialised correctly.
- an ERR_PTR if it failed to initialise.
- NULL before initialisation and after shutdown.

Fixes: d03c720e03bd ("kunit: Add APIs for managing devices")
Signed-off-by: David Gow <davidgow@google.com>
Reviewed-by: Rae Moar <rmoar@google.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

Pull kunit fixes from Shuah Khan:
 "NULL vs IS_ERR() bug fixes, documentation update, MAINTAINERS file
  update to add Rae Moar as a reviewer, and a fix to run test suites
  only after module initialization completes"

* tag 'linux_kselftest-kunit-fixes-6.8-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/shuah/linux-kselftest:
  Documentation: KUnit: Update the instructions on how to test static functions
  kunit: run test suites only after module initialization completes
  MAINTAINERS: kunit: Add Rae Moar as a reviewer
  kunit: device: Fix a NULL vs IS_ERR() check in init()
  kunit: Fix a NULL vs IS_ERR() bug

With the introduction of the pool_rwlock (reader-writer lock), several
fast paths end up taking the pool_rwlock as readers.  Furthermore,
stack_depot_put() unconditionally takes the pool_rwlock as a writer.

Despite allowing readers to make forward-progress concurrently,
reader-writer locks have inherent cache contention issues, which does not
scale well on systems with large CPU counts.

Rework the synchronization story of stack depot to again avoid taking any
locks in the fast paths.  This is done by relying on RCU-protected list
traversal, and the NMI-safe subset of RCU to delay reuse of freed stack
records.  See code comments for more details.

Along with the performance issues, this also fixes incorrect nesting of
rwlock within a raw_spinlock, given that stack depot should still be
usable from anywhere:

 | [ BUG: Invalid wait context ]
 | -----------------------------
 | swapper/0/1 is trying to lock:
 | ffffffff89869be8 (pool_rwlock){..--}-{3:3}, at: stack_depot_save_flags
 | other info that might help us debug this:
 | context-{5:5}
 | 2 locks held by swapper/0/1:
 |  #0: ffffffff89632440 (rcu_read_lock){....}-{1:3}, at: __queue_work
 |  #1: ffff888100092018 (&pool->lock){-.-.}-{2:2}, at: __queue_work  <-- raw_spin_lock

Stack depot usage stats are similar to the previous version after a KASAN
kernel boot:

 $ cat /sys/kernel/debug/stackdepot/stats
 pools: 838
 allocations: 29865
 frees: 6604
 in_use: 23261
 freelist_size: 1879

The number of pools is the same as previously.  The freelist size is
minimally larger, but this may also be due to variance across system
boots.  This shows that even though we do not eagerly wait for the next
RCU grace period (such as with synchronize_rcu() or call_rcu()) after
freeing a stack record - requiring depot_pop_free() to "poll" if an entry
may be used - new allocations are very likely to happen in later RCU grace
periods.

Link: https://lkml.kernel.org/r/20240118110216.2539519-2-elver@google.com
Fixes: 108be8def46e ("lib/stackdepot: allow users to evict stack traces")
Reported-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Add a few basic stats counters for stack depot that can be used to derive
if stack depot is working as intended.  This is a snapshot of the new
stats after booting a system with a KASAN-enabled kernel:

 $ cat /sys/kernel/debug/stackdepot/stats
 pools: 838
 allocations: 29861
 frees: 6561
 in_use: 23300
 freelist_size: 1840

Generally, "pools" should be well below the max; once the system is
booted, "in_use" should remain relatively steady.

Link: https://lkml.kernel.org/r/20240118110216.2539519-1-elver@google.com
Signed-off-by: Marco Elver <elver@google.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>