Re: [PATCH 2/2] scsi: ufs: Protect PM ops and err_handler from user access through sysfs

Can Guo
2021-01-12T00:47:15Z

On 2021-01-11 18:04, Bean Huo wrote:
> On Mon, 2021-01-11 at 17:22 +0800, Can Guo wrote:
>> > > meaning you are tring to access a register when clocks are
>> > > disabled.
>> > > This
>> > > leads to system CRASH.
>> > >
>> >
>> > OK, let it simple, share this kind of crash log becuase of access
>> > sysfs
>> > node in the shutdown flow.
>> >
>> >
>> > > [2] OCP is over current protection. While UFS shutting down, you
>> > > may
>> > > have put UFS regulators to LPM. After that, if you are still
>> > > trying
>> > > to
>> > > talk to UFS, OCP can happen on VCCQ/VCCQ2. This leads to system
>> > > CRASH
>> > > too.
>> >
>> > the same as above, share the crash log.
>> >
>>
>> If you have hand-on experiences on NoC and/or OCP issues, you won't
>> ask
>> for the crash log. The tricky parts about critial NoC and OCP issues
>> is
>
> OK, interesting. would you tell me which register access node in ufs-
> sysfs.c can trigger this crash? let me verify your statement.
>
>

I believe I have explained enough to prove we need this change.

If you are really interested in NoC and OCP, feel free to ping me
on teams, I will show you how to trigger one and what is it like
on my setup.

Can Guo.

> Bean
>
>>