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SubjectRe: [PATCH] tpm: Revert "tpm: fix invalid locking in NONBLOCKING mode"
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On Tue, 2020-05-26 at 15:19 -0700, Alex Guzman wrote:
[...]
> When using your patch, I get a hang when trying to use tpm2_getcap,
> and dmesg shows some info.

Are you sure it's all applied? This

> [ 570.913803] tpm_tcg_write_bytes+0x2f/0x40
> [ 570.913805] release_locality+0x49/0x220
> [ 570.913807] tpm_relinquish_locality+0x1f/0x40
> [ 570.913808] tpm_chip_stop+0x21/0x40
> [ 570.913810] tpm_put_ops+0x9/0x30
> [ 570.913811] tpm_common_write+0x179/0x190
> [ 570.913813] vfs_write+0xb1/0x1a0

Implies an unmatched tpm_put_ops() in the async write path, as though
this hunk:

> @@ -211,11 +202,19 @@ 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;
> }

Is missing. I actually booted the patch in my TPM based VM and it all
seems to work OK when I execute tpm2_getcap (I verified it's using
O_NONBLOCK) and tssgetcapability in sync mode.

James

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