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

From: Jarkko Sakkinen
Date: Wed Dec 11 2019 - 13:10:35 EST

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.