Re: hwmon: (sis5595) potential null pointer dereference in probe

From: Guenter Roeck
Date: Tue Aug 04 2020 - 10:39:59 EST

On 8/4/20 4:50 AM, Evgeny Novikov wrote:
> sis5595_pci_probe() registers platform driver callbacks and just then
> initializes global pointer variable s_bridge. sis5595_probe() may
> dereference it before this happens that can result in null pointer
> dereference.
sis5595_probe() is only called after the device is registered,
which happens in sis5595_device_add() after s_bridge is set. This is
a southbridge, so there won't be any hot insertion/removal events.

> We can not swap registration of platform driver callbacks with
> initialization of s_bridge since sm_sis5595_exit() assumes the
> current order. Perhaps it has sense to implement a pci_driver.remove
> callback that will take care about deregistration of platform driver
> callbacks.

Agreed regarding the remove function. However, given the age of the chip,
I'd rather remove the driver than spending time on cleanup efforts.
This looks like a perfect candidate for depreciation.