2017-04-18 01:58:38

by Stefan Berger

Subject: [PATCH] tpm: Fix reference count to main device

The main device is currently not properly released due to one additional
reference to the 'devs' device which is only released in case of a TPM 2.
So, also get the additional reference only in case of a TPM2.

Fixes: fdc915f7f719 ("tpm: expose spaces via a device link /dev/tpmrm<n>")
Signed-off-by: Stefan Berger <[email protected]>

---
drivers/char/tpm/tpm-chip.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index a321bd5..9dec9f5 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -191,9 +191,10 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
/* get extra reference on main device to hold on
* behalf of devs. This holds the chip structure
* while cdevs is in use. The corresponding put
- * is in the tpm_devs_release
+ * is in the tpm_devs_release (TPM2 only)
*/
- get_device(&chip->dev);
+ if (chip->flags & TPM_CHIP_FLAG_TPM2)
+ get_device(&chip->dev);

if (chip->dev_num == 0)
chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
--
2.4.3

2017-04-19 15:30:45

by Jarkko Sakkinen

Subject: Re: [PATCH] tpm: Fix reference count to main device

On Mon, Apr 17, 2017 at 09:58:26PM -0400, Stefan Berger wrote:
> The main device is currently not properly released due to one additional
> reference to the 'devs' device which is only released in case of a TPM 2.
> So, also get the additional reference only in case of a TPM2.
>
> Fixes: fdc915f7f719 ("tpm: expose spaces via a device link /dev/tpmrm<n>")
> Signed-off-by: Stefan Berger <[email protected]>

Excellent, thank you. I'll send this with some other small fixes for
4.12 to James rather sooner than later.

Reviewed-by: Jarkko Sakkinen <[email protected]>

/Jarkko

>
> ---
> drivers/char/tpm/tpm-chip.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index a321bd5..9dec9f5 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -191,9 +191,10 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
> /* get extra reference on main device to hold on
> * behalf of devs. This holds the chip structure
> * while cdevs is in use. The corresponding put
> - * is in the tpm_devs_release
> + * is in the tpm_devs_release (TPM2 only)
> */
> - get_device(&chip->dev);
> + if (chip->flags & TPM_CHIP_FLAG_TPM2)
> + get_device(&chip->dev);
>
> if (chip->dev_num == 0)
> chip->dev.devt = MKDEV(MISC_MAJOR, TPM_MINOR);
> --
> 2.4.3
>