On Tue, 2021-12-28 at 21:06 -0800, Tadeusz Struk wrote:
When an invalid (non existing) handle is used in a tpm command,
~~~ TPM
that uses the resource manager interface (/dev/tpmrm0) the resource manager tries to load it from its internal cache, but fails and returns an -EINVAL error to the caller. The async handler doesn't handle these error cases currently and the condition in the poll handler never returns mask with EPOLLIN set. The result is that the poll call blocks and the application gets stuck until the user_read_timer wakes it up after 120 sec. Make sure that error conditions also contribute to the poll mask so that a correct error code could passed back to the caller.
I'm not sure what "making sure" means.
Cc: Jarkko Sakkinen jarkko@kernel.org Cc: Jason Gunthorpe jgg@ziepe.ca Cc: linux-integrity@vger.kernel.org Cc: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org Fixes: 9e1b74a63f77 ("tpm: add support for nonblocking operation") Signed-off-by: Tadeusz Struk tstruk@gmail.com
Changes in v2:
- Updated commit message with better problem description.
- Fixed typeos.
drivers/char/tpm/tpm-dev-common.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c index c08cbb306636..fe2679f84cb6 100644 --- a/drivers/char/tpm/tpm-dev-common.c +++ b/drivers/char/tpm/tpm-dev-common.c @@ -69,7 +69,7 @@ static void tpm_dev_async_work(struct work_struct *work) ret = tpm_dev_transmit(priv->chip, priv->space, priv-
data_buffer,
sizeof(priv->data_buffer)); tpm_put_ops(priv->chip); - if (ret > 0) { + if (ret != 0) {
What if ret < 0?
You should explain this change in the commit message. Also, consider adding an inline comment.
priv->response_length = ret; mod_timer(&priv->user_read_timer, jiffies + (120 * HZ)); }
BR, Jarkko