[PATCH v2 0/9] thermal/core: Protect thermal device operations against removal

[Guenter Roeck <linux@roeck-us.net>]

Accesses to thermal zones, and with it to thermal zone device operations,
are still possible after the thermal zone device has been unregistered.
For example, thermal_zone_get_temp() can be called from temp_show()
in thermal_sysfs.c if the sysfs attribute was opened before the thermal
device was unregistered. This is problematic and may result in crashes
since the operations data structure and the underlying code may be gone
when the calls are made.

The following series solves the problem by protecting accesses to thermal
device operations with the thermal device mutex, and by verifying that the
thermal device is still registered after the mutex has been acquired.

This was previously sent as RFC/RFT as single patch [1]. The code was reworked
to match thermal subsystem changes made between v6.0 and v6.1, and it was
split into several patches to simplify review.

[1] https://lore.kernel.org/linux-pm/20221004033936.1047691-1-linux@roeck-us.net/

v2: Improved documentation, rearranged code.
    No functional changes. See individual patches for details.

----------------------------------------------------------------
Guenter Roeck (9):
      thermal/core: Destroy thermal zone device mutex in release function
      thermal/core: Delete device under thermal device zone lock
      thermal/core: Ensure that thermal device is registered in thermal_zone_get_temp
      thermal/core: Move parameter validation from __thermal_zone_get_temp to thermal_zone_get_temp
      thermal/core: Introduce locked version of thermal_zone_device_update
      thermal/core: Protect hwmon accesses to thermal operations with thermal zone mutex
      thermal/core: Protect sysfs accesses to thermal operations with thermal zone mutex
      thermal/core: Remove thermal_zone_set_trips()
      thermal/core: Protect thermal device operations against thermal device removal

 drivers/thermal/thermal_core.c    | 76 +++++++++++++++++++++++--------------
 drivers/thermal/thermal_core.h    |  3 +-
 drivers/thermal/thermal_helpers.c | 67 +++++++++++++++++++++------------
 drivers/thermal/thermal_hwmon.c   | 10 ++++-
 drivers/thermal/thermal_sysfs.c   | 79 ++++++++++++++++++++++++++++++++-------
 5 files changed, 168 insertions(+), 67 deletions(-)