On Thu, Feb 23, 2017 at 02:19:14PM -0700, Jason Gunthorpe wrote:
> Once cdev_add is done the device node is visible to user space and
> could have been opened. Thus we have to go through the locking
> process in tpm_del_char_device if device_add fails.
>
> Fixes: 2c91ce8523a ("tpm: fix the rollback in tpm_chip_register()")
> Signed-off-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Jarkko Sakkinen <[email protected]>
/Jarkko
> ---
> drivers/char/tpm/tpm-chip.c | 43 ++++++++++++++++++++++---------------------
> 1 file changed, 22 insertions(+), 21 deletions(-)
>
> static function moved to avoid a prototype
>
> This was noticed while reviewing the cdev patchset from Logan
>
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index a77262d31911a1..c82acf0a6e7353 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -226,6 +226,26 @@ struct tpm_chip *tpmm_chip_alloc(struct device *pdev,
> }
> EXPORT_SYMBOL_GPL(tpmm_chip_alloc);
>
> +static void tpm_del_char_device(struct tpm_chip *chip, bool with_device)
> +{
> + cdev_del(&chip->cdev);
> + if (with_device) {
> + device_del(&chip->dev);
> +
> + /* Make the chip unavailable. */
> + mutex_lock(&idr_lock);
> + idr_replace(&dev_nums_idr, NULL, chip->dev_num);
> + mutex_unlock(&idr_lock);
> + }
> +
> + /* 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);
> +}
> +
> static int tpm_add_char_device(struct tpm_chip *chip)
> {
> int rc;
> @@ -246,8 +266,7 @@ static int tpm_add_char_device(struct tpm_chip *chip)
> "unable to device_register() %s, major %d, minor %d,
> err=%d\n",
> dev_name(&chip->dev), MAJOR(chip->dev.devt),
> MINOR(chip->dev.devt), rc);
> -
> - cdev_del(&chip->cdev);
> + tpm_del_char_device(chip, false);
> return rc;
> }
>
> @@ -259,24 +278,6 @@ static int tpm_add_char_device(struct tpm_chip *chip)
> return rc;
> }
>
> -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);
> - idr_replace(&dev_nums_idr, NULL, chip->dev_num);
> - mutex_unlock(&idr_lock);
> -
> - /* 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);
> -}
> -
> static void tpm_del_legacy_sysfs(struct tpm_chip *chip)
> {
> struct attribute **i;
> @@ -384,6 +385,6 @@ void tpm_chip_unregister(struct tpm_chip *chip)
> {
> tpm_del_legacy_sysfs(chip);
> tpm_bios_log_teardown(chip);
> - tpm_del_char_device(chip);
> + tpm_del_char_device(chip, true);
> }
> EXPORT_SYMBOL_GPL(tpm_chip_unregister);
> --
> 2.7.4
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