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Date: Thu, 28 May 2020 03:30:40 +0300 From: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com> To: Tadeusz Struk <tstruk@...il.com> Cc: James Bottomley <James.Bottomley@...senPartnership.com>, Mario Limonciello <mario.limonciello@...l.com>, Peter Huewe <peterhuewe@....de>, Jason Gunthorpe <jgg@...pe.ca>, Arnd Bergmann <arnd@...db.de>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org, Jeffrin Jose T <jeffrin@...agiritech.edu.in>, Alex Guzman <alex@...man.io> Subject: Re: [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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