On Fri, 2021-09-10 at 20:04 +0200, Lino Sanfilippo wrote:

In tpm_del_char_device() make sure that chip->ops is still valid.
This check is needed since in case of a system shutdown
tpm_class_shutdown() has already been called and set chip->ops to NULL.
This leads to a NULL pointer access as soon as tpm_del_char_device()
tries to access chip->ops in case of TPM 2.

Fixes: dcbeab1946454 ("tpm: fix crash in tpm_tis deinitialization")
Cc: stable@vger.kernel.org
Signed-off-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
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Have you been able to reproduce this in some environment?

/Jarkko