Re: [PATCH] tpm: fix WARNING: lock held when returning to user space

Jarkko Sakkinen
2019-12-11T18:00:52Z

On Wed, Dec 11, 2019 at 07:52:02PM +0200, Jarkko Sakkinen wrote:
> On Tue, Dec 10, 2019 at 01:17:51PM -0800, Tadeusz Struk wrote:
> > When an application sends TPM commands in NONBLOCKING mode
> > the driver holds chip->tpm_mutex returning from write(),
> > which triggers WARNING: lock held when returning to user space!
> > To silence this warning the driver needs to release the mutex
> > and acquire it again in tpm_dev_async_work() before sending
> > the command.
>
> This commit message is nonsense ATM. The code leaves locks held,
> which is unacceptable.
>
> Silencing warnings is worst possible rationale for a code change
> that I can think of starting from the fact that is straight out
> wrong and malicious.

The code change, however, seems to be doing the right thing.

Please bundle it with the test and fix the commit message
appropriately.

/Jarkko