[GIT PULL kcsan] KCSAN commits for v5.15

[Paul E. McKenney]

Hello, Ingo,

This pull request contains updates for the Kernel concurrency sanitizer
(KCSAN).

These updates improve comments, introduce CONFIG_KCSAN_STRICT (which RCU
uses), optimize use of get_ctx() by kcsan_found_watchpoint(), rework
atomic.h into permissive.h, and add the ability to ignore writes that
change only one bit of a given data-racy variable.

These updates have been posted on LKML:

https://lore.kernel.org/lkml/20210721210726.GA828672@paulmck-ThinkPad-P17-Gen-1/

These changes are based on v5.14-rc2, have been exposed to -next and to
kbuild test robot, and are available in the Git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git kcsan

for you to fetch changes up to e04938042d77addc7f41d983aebea125cddbed33:

  kcsan: Make strict mode imply interruptible watchers (2021-07-20 13:49:44 -0700)

----------------------------------------------------------------
Marco Elver (8):
      kcsan: Improve some Kconfig comments
      kcsan: Remove CONFIG_KCSAN_DEBUG
      kcsan: Introduce CONFIG_KCSAN_STRICT
      kcsan: Reduce get_ctx() uses in kcsan_found_watchpoint()
      kcsan: Rework atomic.h into permissive.h
      kcsan: Print if strict or non-strict during init
      kcsan: permissive: Ignore data-racy 1-bit value changes
      kcsan: Make strict mode imply interruptible watchers

 Documentation/dev-tools/kcsan.rst | 12 +++++
 kernel/kcsan/atomic.h             | 23 ----------
 kernel/kcsan/core.c               | 77 ++++++++++++++++++++------------
 kernel/kcsan/kcsan_test.c         | 32 +++++++++++++
 kernel/kcsan/permissive.h         | 94 +++++++++++++++++++++++++++++++++++++++
 lib/Kconfig.kcsan                 | 42 ++++++++++++-----
 6 files changed, 217 insertions(+), 63 deletions(-)
 delete mode 100644 kernel/kcsan/atomic.h
 create mode 100644 kernel/kcsan/permissive.h