On Fri, Nov 5, 2021 at 5:19 PM Daniel Lezcano daniel.lezcano@linaro.org wrote:
On 05/11/2021 16:14, Rafael J. Wysocki wrote:
On Fri, Nov 5, 2021 at 12:57 AM Subbaraman Narayanamurthy quic_subbaram@quicinc.com wrote:
of_parse_thermal_zones() parses the thermal-zones node and registers a thermal_zone device for each subnode. However, if a thermal zone is consuming a thermal sensor and that thermal sensor device hasn't probed yet, an attempt to set trip_point_*_temp for that thermal zone device can cause a NULL pointer dereference. Fix it.
console:/sys/class/thermal/thermal_zone87 # echo 120000 > trip_point_0_temp ... Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 ... Call trace: of_thermal_set_trip_temp+0x40/0xc4 trip_point_temp_store+0xc0/0x1dc dev_attr_store+0x38/0x88 sysfs_kf_write+0x64/0xc0 kernfs_fop_write_iter+0x108/0x1d0 vfs_write+0x2f4/0x368 ksys_write+0x7c/0xec __arm64_sys_write+0x20/0x30 el0_svc_common.llvm.7279915941325364641+0xbc/0x1bc do_el0_svc+0x28/0xa0 el0_svc+0x14/0x24 el0_sync_handler+0x88/0xec el0_sync+0x1c0/0x200
While at it, fix the possible NULL pointer dereference in other functions as well: of_thermal_get_temp(), of_thermal_set_emul_temp(), of_thermal_get_trend().
Can the subject be more specific, please?
The issue appears to be limited to the of_thermal_ family of functions, but the subject doesn't reflect that at all.
Suggested-by: David Collins quic_collinsd@quicinc.com Signed-off-by: Subbaraman Narayanamurthy quic_subbaram@quicinc.com
Daniel, any concerns regarding the code changes below?
I've a concern about the root cause but I did not have time to investigate how to fix it nicely.
thermal_of is responsible of introducing itself between the thermal core code and the backend. So it defines the ops which in turn call the sensor ops leading us to this problem.
So, without a better solution, this fix can be applied until we rethink the thermal_of approach.
Acked-by: Daniel Lezcano daniel.lezcano@linaro.org
Thanks!
I've queued it up for 5.16-rc as "thermal: Fix NULL pointer dereferences in of_thermal_ functions".