[PATCH v3 19/20] coresight: add try_get_module() in coresight_grab_device()

[Suzuki K Poulose]

On 07/22/2020 11:49 AM, Suzuki K Poulose wrote:
> Hi Tingwei,
> 
> On 07/17/2020 06:45 AM, Tingwei Zhang wrote:
>> When coresight device is in an active session, driver module of
>> that device should not be removed. Use try_get_module() in
>> coresight_grab_device() to prevent module to be unloaded.
>>
> 
> Is this really sufficient ? AFAIU, a device could be removed, but the
> module may still be alive due to the refcount on the module. This
> could imply that we have stale pointers in the _path_, which could
> lead to corruption elsewhere. Should we do a get/put_device() instead ?

Also, logically this refcount solution patch must be applied before
the drivers are made modules to prevent breaking bisection failures.
So, please re-order the patches in the series to take that into
consideration.

Suzuki