---
- branch: MAIN
  date: Fri Dec 31 14:30:04 UTC 2021
  files:
  - new: '1.150'
    old: '1.149'
    path: src/sys/dev/sysmon/sysmon_envsys.c
    pathrev: src/sys/dev/sysmon/sysmon_envsys.c@1.150
    type: modified
  - new: '1.123'
    old: '1.122'
    path: src/sys/dev/sysmon/sysmon_envsys_events.c
    pathrev: src/sys/dev/sysmon/sysmon_envsys_events.c@1.123
    type: modified
  - new: '1.52'
    old: '1.51'
    path: src/sys/dev/sysmon/sysmonvar.h
    pathrev: src/sys/dev/sysmon/sysmonvar.h@1.52
    type: modified
  id: 20211231T143004Z.d6dff0c9b2c1948b2829d40d6442f8ee6ee75b05
  log: |
    sysmon(9): Fix callout/thread synchronization.

    Callout may ONLY take sme_work_mtx, at IPL_SOFTCLOCK; MUST NOT touch
    sme_mtx at IPL_NONE.  All state the callout needs is serialized by
    sme_work_mtx now:

    - calls to sme_schedule_callout
    - calls to sme_schedule_halt
    - struct sysmon_envsys::sme_events_timeout
    - struct sysmon_envsys::sme_events_list
    - struct sysmon_envsys::sme_callout_state
    - struct envsys_data::flags
      => yes, this is a little silly -- used for ENVSYS_FNEED_REFRESH
      => should maybe separate the static driver-defined features from
         the state flags needed by sysmon_envsys but not important now

    Sleeping under sme_work_mtx (except on other adaptive locks at
    IPL_SOFTCLOCK) is forbidden.  Calling out to the driver under
    sme_work_mtx is forbidden.

    This should properly fix:

    https://mail-index.netbsd.org/tech-kern/2015/10/14/msg019511.html
    PR kern/56592
  module: src
  subject: 'CVS commit: src/sys/dev/sysmon'
  unixtime: '1640961004'
  user: riastradh