tpm: fix invalid locking in NONBLOCKING mode (d23d1248) · Commits · 戴 / test

When an application sends TPM commands in NONBLOCKING mode the driver holds chip->tpm_mutex returning from write(), which triggers: "WARNING: lock held when returning to user space". To fix this issue the driver needs to release the mutex before returning and acquire it again in tpm_dev_async_work() before sending the command. Cc: stable@vger.kernel.org Fixes: (tpm: add support for nonblocking operation) Reported-by:

Jeffrin Jose T <jeffrin@rajagiritech.edu.in> Tested-by:

Jeffrin Jose T <jeffrin@rajagiritech.edu.in> Signed-off-by:

Tadeusz Struk <tadeusz.struk@intel.com> Reviewed-by:

Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by:

Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>

drivers/char/tpm/tpm-dev-common.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -61,6 +61,12 @@ static void tpm_dev_async_work(struct work_struct *work)

		mutex_lock(&priv->buffer_mutex);
		priv->command_enqueued = false;
		ret = tpm_try_get_ops(priv->chip);
		if (ret) {
		priv->response_length = ret;
		goto out;
		}

		ret = tpm_dev_transmit(priv->chip, priv->space, priv->data_buffer,
		sizeof(priv->data_buffer));
		tpm_put_ops(priv->chip);
		@@ -68,6 +74,7 @@ static void tpm_dev_async_work(struct work_struct *work)
		priv->response_length = ret;
		mod_timer(&priv->user_read_timer, jiffies + (120 * HZ));
		}
		out:
		mutex_unlock(&priv->buffer_mutex);
		wake_up_interruptible(&priv->async_wait);
		}
		@@ -204,6 +211,7 @@ ssize_t tpm_common_write(struct file file, const char __user buf,
		if (file->f_flags & O_NONBLOCK) {
		priv->command_enqueued = true;
		queue_work(tpm_dev_wq, &priv->async_work);
		tpm_put_ops(priv->chip);
		mutex_unlock(&priv->buffer_mutex);
		return size;
		}

Admin message