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SubjectRe: [PATCH] tpm: Revert "tpm: fix invalid locking in NONBLOCKING mode"
On Tue, May 26, 2020 at 12:39:37PM -0700, Tadeusz Struk wrote:
> On 5/26/20 12:14 PM, James Bottomley wrote:
> > + /* 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;
> > + }
> > +
> Hi James,
> This won't help if the message is read by an async tcti. If the problem lies
> in the chip get locality code, perhaps this could help to debug the root-cause
> instead of masking it out in the upper layer code:

What is TCTI and async TCTI? Not following.

> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> index 2435216bd10a..da5ecd0376bf 100644
> --- a/drivers/char/tpm/tpm_tis_core.c
> +++ b/drivers/char/tpm/tpm_tis_core.c
> @@ -202,20 +202,22 @@ static int request_locality(struct tpm_chip *chip, int l)
> return rc;
>
> stop = jiffies + chip->timeout_a;
> + timeout = stop - jiffies;
>
> if (chip->flags & TPM_CHIP_FLAG_IRQ) {
> again:
> timeout = stop - jiffies;
> if ((long)timeout <= 0)
> - return -1;
> + goto out;
> +
> rc = wait_event_interruptible_timeout(priv->int_queue,
> - (check_locality
> - (chip, l)),
> + check_locality(chip, l),
> timeout);
> if (rc > 0)
> return l;
> if (rc == -ERESTARTSYS && freezing(current)) {
> clear_thread_flag(TIF_SIGPENDING);
> + timeout = stop - jiffies;
> goto again;
> }
> } else {
> @@ -226,6 +228,10 @@ static int request_locality(struct tpm_chip *chip, int l)
> tpm_msleep(TPM_TIMEOUT);
> } while (time_before(jiffies, stop));
> }
> +out:
> + dev_warn(&chip->dev, "%s: failed to request locality %d after %lu ms\n",
> + __func__, l, timeout * HZ / 1000);
> +
> return -1;
> }
>

/Jarkko

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