Revert "hwmon: (ibmpex) fix use-after-free in high/low store"

In the Linux kernel, the following vulnerability has been resolved:

Revert "hwmon: (ibmpex) fix use-after-free in high/low store"

This reverts commit 6946c726c3f4c36f0f049e6f97e88c510b15f65d.

Jean Delvare points out that the patch does not completely

fix the reported problem, that it in fact introduces a

(new) race condition, and that it may actually not be needed in

the first place.

Various AI reviews agree. Specific and relevant AI feedback:

"

This reordering sets the driver data to NULL before removing the sensor

attributes in the loop below.

ibmpex_show_sensor() retrieves this driver data via dev_get_drvdata() but

does not check if it is NULL before dereferencing it to access

data->sensors[].

If a userspace process reads a sensor file (like temp1_input) while this

delete function is running, could it race with the dev_set_drvdata(...,

NULL) call here and crash in ibmpex_show_sensor()?

Would it be safer to keep the original order where device_remove_file() is

called before clearing the driver data? device_remove_file() should wait

for any active sysfs callbacks to complete, which might already prevent the

use-after-free this patch intends to fix.

"

Revert the offending patch. If it can be shown that the originally reported

alleged race condition does indeed exist, it can always be re-introduced

with a complete fix.