On Tue, Feb 09, 2021 at 12:52:17PM +0100, Lino Sanfilippo wrote:

quoted

@@ -640,8 +643,10 @@ void tpm_chip_unregister(struct tpm_chip *chip)
 	if (IS_ENABLED(CONFIG_HW_RANDOM_TPM))
 		hwrng_unregister(&chip->hwrng);
 	tpm_bios_log_teardown(chip);
-	if (chip->flags & TPM_CHIP_FLAG_TPM2)
+	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
 		cdev_device_del(&chip->cdevs, &chip->devs);
+		put_device(&chip->devs);
+	}
 	tpm_del_char_device(chip);
 }
 EXPORT_SYMBOL_GPL(tpm_chip_unregister);

I tested the solution you scetched and it fixes the issue for me. Will you send a (real) patch for this?

No, feel free to bundle this up with any fixes needed and send it with
a Signed-off-by from both of us

I did it pretty fast so it will need a careful read that there isn't a
typo

Thanks,
Jason