linux-kernel - Re: [PATCH v3 2/2] tpm: in tpm2_del_space check if ops pointer is still valid

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Date:   Tue, 9 Feb 2021 09:36:53 -0400
From:   Jason Gunthorpe <jgg@...pe.ca>
To:     Lino Sanfilippo <l.sanfilippo@...bus.com>
Cc:     James Bottomley <James.Bottomley@...senPartnership.com>,
        Jarkko Sakkinen <jarkko@...nel.org>,
        Lino Sanfilippo <LinoSanfilippo@....de>, peterhuewe@....de,
        stefanb@...ux.vnet.ibm.com, stable@...r.kernel.org,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/2] tpm: in tpm2_del_space check if ops pointer is
 still valid

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