Commit d972b052 authored by Jarkko Sakkinen's avatar Jarkko Sakkinen Committed by Peter Huewe
Browse files

tpm: fix call order in tpm-chip.c 



- tpm_dev_add_device(): cdev_add() must be done before uevent is
  propagated in order to avoid races.
- tpm_chip_register(): tpm_dev_add_device() must be done as the
  last step before exposing device to the user space in order to
  avoid races.

In addition clarified description in tpm_chip_register().

Fixes: 313d21ee ("tpm: device class for tpm")
Fixes: afb5abc2 ("tpm: two-phase chip management functions")

Signed-off-by: default avatarJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: default avatarPeter Huewe <peterhuewe@gmx.de>
Signed-off-by: default avatarPeter Huewe <peterhuewe@gmx.de>
parent 6da2517d

drivers/char/tpm/tpm-chip.c

+14 −20
Original line number Diff line number Diff line
@@ -140,24 +140,24 @@ static int tpm_dev_add_device(struct tpm_chip *chip) 
{

	int rc;



	rc = device_add(&chip->dev);

	rc = cdev_add(&chip->cdev, chip->dev.devt, 1);

	if (rc) {

		dev_err(&chip->dev,

			"unable to device_register() %s, major %d, minor %d, err=%d\n",

			"unable to cdev_add() %s, major %d, minor %d, err=%d\n",

			chip->devname, MAJOR(chip->dev.devt),

			MINOR(chip->dev.devt), rc);



		device_unregister(&chip->dev);

		return rc;

	}



	rc = cdev_add(&chip->cdev, chip->dev.devt, 1);

	rc = device_add(&chip->dev);

	if (rc) {

		dev_err(&chip->dev,

			"unable to cdev_add() %s, major %d, minor %d, err=%d\n",

			"unable to device_register() %s, major %d, minor %d, err=%d\n",

			chip->devname, MAJOR(chip->dev.devt),

			MINOR(chip->dev.devt), rc);



		device_unregister(&chip->dev);

		return rc;

	}
@@ -174,27 +174,17 @@ static void tpm_dev_del_device(struct tpm_chip *chip) 
 * tpm_chip_register() - create a character device for the TPM chip

 * @chip: TPM chip to use.

 *

 * Creates a character device for the TPM chip and adds sysfs interfaces for

 * the device, PPI and TCPA. As the last step this function adds the

 * chip to the list of TPM chips available for use.

 * Creates a character device for the TPM chip and adds sysfs attributes for

 * the device. As the last step this function adds the chip to the list of TPM

 * chips available for in-kernel use.

 *

 * NOTE: This function should be only called after the chip initialization

 * is complete.

 *

 * Called from tpm_<specific>.c probe function only for devices

 * the driver has determined it should claim.  Prior to calling

 * this function the specific probe function has called pci_enable_device

 * upon errant exit from this function specific probe function should call

 * pci_disable_device

 * This function should be only called after the chip initialization is

 * complete.

 */

int tpm_chip_register(struct tpm_chip *chip)

{

	int rc;



	rc = tpm_dev_add_device(chip);

	if (rc)

		return rc;



	/* Populate sysfs for TPM1 devices. */

	if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {

		rc = tpm_sysfs_add_device(chip);
@@ -208,6 +198,10 @@ int tpm_chip_register(struct tpm_chip *chip) 
		chip->bios_dir = tpm_bios_log_setup(chip->devname);

	}



	rc = tpm_dev_add_device(chip);

	if (rc)

		return rc;



	/* Make the chip available. */

	spin_lock(&driver_lock);

	list_add_rcu(&chip->list, &tpm_chip_list);

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