[PATCH v2 0/2] sysfs: add counters for lockups and stalls

[Max Kellermann <max.kellermann@ionos.com>]

Commits 9db89b411170 ("exit: Expose "oops_count" to sysfs") and
8b05aa263361 ("panic: Expose "warn_count" to sysfs") added counters
for oopses and warnings to sysfs, and these two patches do the same
for hard/soft lockups and RCU stalls.

All of these counters are useful for monitoring tools to detect
whether the machine is healthy.  If the kernel has experienced a
lockup or a stall, it's probably due to a kernel bug, and I'd like to
detect that quickly and easily.  There is currently no way to detect
that, other than parsing dmesg.  Or observing indirect effects: such
as certain tasks not responding, but then I need to observe all tasks,
and it may take a while until these effects become visible/measurable.
I'd rather be able to detect the primary cause more quickly, possibly
before everything falls apart.

Max Kellermann (2):
  kernel/watchdog: add /sys/kernel/{hard,soft}lockup_count
  kernel/rcu/tree_stall: add /sys/kernel/rcu_stall_count

 .../ABI/testing/sysfs-kernel-hardlockup_count |  7 +++
 .../ABI/testing/sysfs-kernel-rcu_stall_count  |  6 +++
 .../ABI/testing/sysfs-kernel-softlockup_count |  7 +++
 kernel/rcu/tree_stall.h                       | 26 +++++++++
 kernel/watchdog.c                             | 53 +++++++++++++++++++
 5 files changed, 99 insertions(+)
 create mode 100644 Documentation/ABI/testing/sysfs-kernel-hardlockup_count
 create mode 100644 Documentation/ABI/testing/sysfs-kernel-rcu_stall_count
 create mode 100644 Documentation/ABI/testing/sysfs-kernel-softlockup_count

-- 
2.47.2