* [PATCH 1/1] tpm: fix TIS locality timeout problems
[not found] <20200602074218.12142-1-ivan.hu@canonical.com>
@ 2020-06-02 7:42 ` Ivan Hu
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From: Ivan Hu @ 2020-06-02 7:42 UTC (permalink / raw)
To: acelan.kao; +Cc: James Bottomley, stable, Ivan Hu
From: James Bottomley <James.Bottomley@HansenPartnership.com>
BugLink: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1881710
It has been reported that some TIS based TPMs are giving unexpected
errors when using the O_NONBLOCK path of the TPM device. The problem
is that some TPMs don't like it when you get and then relinquish a
locality (as the tpm_try_get_ops()/tpm_put_ops() pair does) without
sending a command. This currently happens all the time in the
O_NONBLOCK write path. Fix this by moving the tpm_try_get_ops()
further down the code to after the O_NONBLOCK determination is made.
This is safe because the priv->buffer_mutex still protects the priv
state being modified.
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206275
Fixes: d23d12484307 ("tpm: fix invalid locking in NONBLOCKING mode")
Reported-by: Mario Limonciello <Mario.Limonciello@dell.com>
Tested-by: Alex Guzman <alex@guzman.io>
Cc: stable@vger.kernel.org
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Ivan Hu <ivan.hu@canonical.com>
---
drivers/char/tpm/tpm-dev-common.c | 19 +++++++++----------
1 file changed, 9 insertions(+), 10 deletions(-)
diff --git a/drivers/char/tpm/tpm-dev-common.c b/drivers/char/tpm/tpm-dev-common.c
index 10b9f63701e6..de55205d3a11 100644
--- a/drivers/char/tpm/tpm-dev-common.c
+++ b/drivers/char/tpm/tpm-dev-common.c
@@ -164,15 +164,6 @@ ssize_t tpm_common_write(struct file *file, const char __user *buf,
goto out;
}
- /* atomic tpm command send and result receive. We only hold the ops
- * lock during this period so that the tpm can be unregistered even if
- * the char dev is held open.
- */
- if (tpm_try_get_ops(priv->chip)) {
- ret = -EPIPE;
- goto out;
- }
-
priv->response_length = 0;
priv->response_read = false;
*off = 0;
@@ -186,11 +177,19 @@ 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;
}
+ /* atomic tpm command send and result receive. We only hold the ops
+ * lock during this period so that the tpm can be unregistered even if
+ * the char dev is held open.
+ */
+ if (tpm_try_get_ops(priv->chip)) {
+ ret = -EPIPE;
+ goto out;
+ }
+
ret = tpm_transmit(priv->chip, priv->space, priv->data_buffer,
sizeof(priv->data_buffer), 0);
tpm_put_ops(priv->chip);
--
2.17.1
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2020-06-02 7:42 ` [PATCH 1/1] tpm: fix TIS locality timeout problems Ivan Hu
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