On Sun 2019-10-06 19:20:07, Greg Kroah-Hartman wrote:
From: Jarkko Sakkinen jarkko.sakkinen@linux.intel.com
commit 2677ca98ae377517930c183248221f69f771c921 upstream
Use tpm_try_get_ops() in tpm-sysfs.c so that we can consider moving other decorations (locking, localities, power management for example) inside it. This direction can be of course taken only after other call sites for tpm_transmit() have been treated in the same way.
This changes locking completely:
@@ -244,10 +274,12 @@ static ssize_t cancel_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { struct tpm_chip *chip = to_tpm_chip(dev);
- if (chip == NULL)
- if (tpm_try_get_ops(chip)) return 0;
chip->ops->cancel(chip);
- tpm_put_ops(chip); return count;
} static DEVICE_ATTR_WO(cancel);
For example this did not have any locking, and is now protected by
get_device(&chip->dev);
down_read(&chip->ops_sem);
. Is that intended? Is this known to fix any bugs?
Best regards, Pavel