On Fri, Nov 5, 2021 at 5:19 PM Daniel Lezcano <daniel.lezcano@xxxxxxxxxx> wrote: > > On 05/11/2021 16:14, Rafael J. Wysocki wrote: > > On Fri, Nov 5, 2021 at 12:57 AM Subbaraman Narayanamurthy > > <quic_subbaram@xxxxxxxxxxx> 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@xxxxxxxxxxx> > >> Signed-off-by: Subbaraman Narayanamurthy <quic_subbaram@xxxxxxxxxxx> > > > > 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@xxxxxxxxxx> Thanks! I've queued it up for 5.16-rc as "thermal: Fix NULL pointer dereferences in of_thermal_ functions".
