Commit d56e4f75 authored Nov 07, 2015 by Jarkko Sakkinen

tpm: fix compat 'ppi' link handling in tpm_chip_register()



__compat_only_sysfs_link_entry_to_kobj() was unconditionally called for
TPM1 chips, which caused crash on Acer C720 laptop where DSM for the
ACPI object did not exist.

There are two reasons for unwanted behavior:

* The code did not check whether
  __compat_only_sysfs_link_entry_to_kobj() returned -ENOENT. This is
  OK. It just meanst that ppi is not available.
* The code did not clean up properly. Compat link should added only
  after all other init is done.

This patch sorts out these issues.

Fixes: 9b774d5c
Reported-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jeremiah Mahler <jmmahler@gmail.com>
Acked-by: Peter Huewe <PeterHuewe@gmx.de>

parent 2e31125c

drivers/char/tpm/tpm-chip.c

+10 −8

Original line number	Diff line number	Diff line
		@@ -226,14 +226,6 @@ int tpm_chip_register(struct tpm_chip *chip)
		if (rc)
		goto out_err;

		if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
		rc = __compat_only_sysfs_link_entry_to_kobj(&chip->pdev->kobj,
		&chip->dev.kobj,
		"ppi");
		if (rc)
		goto out_err;
		}

		/* Make the chip available. */
		spin_lock(&driver_lock);
		list_add_tail_rcu(&chip->list, &tpm_chip_list);
		@@ -241,6 +233,16 @@ int tpm_chip_register(struct tpm_chip *chip)

		chip->flags \|= TPM_CHIP_FLAG_REGISTERED;

		if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
		rc = __compat_only_sysfs_link_entry_to_kobj(&chip->pdev->kobj,
		&chip->dev.kobj,
		"ppi");
		if (rc && rc != -ENOENT) {
		tpm_chip_unregister(chip);
		return rc;
		}
		}

		return 0;
		out_err:
		tpm1_chip_unregister(chip);

Admin message