Re: [PATCH] tpm: fix crash in tpm_tis deinitialization

[Jason Gunthorpe]

On Wed, Apr 13, 2016 at 09:58:05AM +0300, Jarkko Sakkinen wrote:
> > > It prevents everything including the kernel from issuing a command
> >                          ^^^^^^^^^^^^^^^^^^^^
> > 
> > That lock is not used to exclude kernel access. Read lock is only taken
> > for the user space device in tpm-dev.c.
> 
> My bad. For the in-kernel API it is taken through tpm_find_get().

Right. At this point any thing that can run in-kernel concurrently
with the write exclusion is a kernel bug. Those places will need to
grab the read side of the lock.

Jason