Re: [PATCH 5.4] thermal: Fix NULL pointer dereferences in of_thermal_ functions

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Aug 02, 2022 at 11:42:16AM +0800, Mark-PK Tsai wrote:
> From: Subbaraman Narayanamurthy <quic_subbaram@quicinc.com>
> 
> commit 96cfe05051fd8543cdedd6807ec59a0e6c409195 upstream.
> 
> 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().
> 
> Suggested-by: David Collins <quic_collinsd@quicinc.com>
> Signed-off-by: Subbaraman Narayanamurthy <quic_subbaram@quicinc.com>
> Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> Cc: stable@vger.kernel.org
> Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
> ---
>  drivers/thermal/of-thermal.c | 9 ++++++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 

Now queued up, thanks.

greg k-h