[BUG] drivers: adm9240: possible data race bug in adm9240_fan_read()

[Li Zhong <floridsleeves@xxxxxxxxx>]

Hello,

My static analysis tool reports a possible bug in the adm9240 driver in Linux
v6.0:

drivers/hwmon/adm9240.c:

adm9240_read()
    adm9240_fan_read() --> Line 509
        adm9240_write_fan_div()

adm9240_write_fan_div() says 'callers must hold
data->update_lock'. However, it seems like the context does
not hold the lock it requires. So it may cause data race when
setting new fan div.

I am not quite sure whether this is a real bug. Any feedback would be
appreciated!

Thanks,
Li Zhong