On Mon, Apr 11, 2016 at 11:40:37AM -0600, Jason Gunthorpe wrote:
> On Mon, Apr 11, 2016 at 07:05:20PM +0300, Jarkko Sakkinen wrote:
> > rmmod crashes the driver because tpm_chip_unregister() already sets ops
> > to NULL. This commit fixes the issue by moving tpm2_shutdown() to
> > tpm_chip_unregister(). This commit is also cleanup because it removes
> > duplicate code from tpm_crb and tpm_tis to the core.
> >
> > Signed-off-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
> > Fixes: 4d3eac5e156a ("tpm: Provide strong locking for device removal")
> > drivers/char/tpm/tpm-chip.c | 3 +++
> > drivers/char/tpm/tpm_crb.c | 3 ---
> > drivers/char/tpm/tpm_tis.c | 3 ---
> > 3 files changed, 3 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> > index f62c851..2642cca 100644
> > +++ b/drivers/char/tpm/tpm-chip.c
> > @@ -361,6 +361,9 @@ void tpm_chip_unregister(struct tpm_chip *chip)
> > if (!(chip->flags & TPM_CHIP_FLAG_REGISTERED))
> > return;
> >
> > + if (chip->flags & TPM_CHIP_FLAG_TPM2)
> > + tpm2_shutdown(chip, TPM2_SU_CLEAR);
> > +
> > if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
> > sysfs_remove_link(&chip->dev.parent->kobj, "ppi");
>
> This needs to be after ops is fenced, something like this.
I would appreciate a supporting argument.
I guess the argument here is that this will prevent user space from
issuing TPM commands after the shutdown command has been sent?
/Jarkko
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 2642cca05cac..2ea2f1561e59 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -269,6 +269,8 @@ static void tpm_del_char_device(struct tpm_chip *chip)
>
> /* Make the driver uncallable. */
> down_write(&chip->ops_sem);
> + if (chip->flags & TPM_CHIP_FLAG_TPM2)
> + tpm2_shutdown(chip, TPM2_SU_CLEAR);
> chip->ops = NULL;
> up_write(&chip->ops_sem);
> }
> @@ -361,9 +363,6 @@ void tpm_chip_unregister(struct tpm_chip *chip)
> if (!(chip->flags & TPM_CHIP_FLAG_REGISTERED))
> return;
>
> - if (chip->flags & TPM_CHIP_FLAG_TPM2)
> - tpm2_shutdown(chip, TPM2_SU_CLEAR);
> -
> if (!(chip->flags & TPM_CHIP_FLAG_TPM2))
> sysfs_remove_link(&chip->dev.parent->kobj, "ppi");
>
