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SubjectRe: [PATCH] tpm: don't destroy chip device prematurely
On Sun, Oct 02, 2016 at 10:39:31AM +0300, Tomas Winkler wrote:
> In tpm_del_char_device device_del is called
> prior to tpm2_shutdown where it is still used.
>
> Fortunately, so far chip->dev was used only for printouts
> int tpm2_shutdown flow, hence system didn't crash. But with
> the introduction of runtime power management it will result in
> shutting down the parent device while it still in use.
>
> Fixes: 20e0152393b41 ("tpm: fix crash in tpm_tis deinitialization")
> Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>

Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

/Jarkko

> ---
> drivers/char/tpm/tpm-chip.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index e5950131bd90..b1cb0aae8e66 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -261,7 +261,6 @@ static int tpm_add_char_device(struct tpm_chip *chip)
> static void tpm_del_char_device(struct tpm_chip *chip)
> {
> cdev_del(&chip->cdev);
> - device_del(&chip->dev);
>
> /* Make the chip unavailable. */
> mutex_lock(&idr_lock);
> @@ -274,6 +273,8 @@ static void tpm_del_char_device(struct tpm_chip *chip)
> tpm2_shutdown(chip, TPM2_SU_CLEAR);
> chip->ops = NULL;
> up_write(&chip->ops_sem);
> +
> + device_del(&chip->dev);
> }
>
> static int tpm1_chip_register(struct tpm_chip *chip)
> --
> 2.7.4
>

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