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SubjectRe: [PATCH] tpm: Revert "tpm: fix invalid locking in NONBLOCKING mode"
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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:

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;
}

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