From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Andrey Pronin <apronin@chromium.org>
Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>,
Peter Huewe <peterhuewe@gmx.de>,
Marcel Selhorst <tpmdd@selhorst.net>,
tpmdd-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org,
semenzato@chromium.org, groeck@chromium.org
Subject: Re: [PATCH] tpm/tpm_i2c_infineon: ensure no ongoing commands on shutdown
Date: Mon, 16 Jan 2017 11:33:18 +0200 [thread overview]
Message-ID: <20170116093318.wmmr2z54pc6k7t2c@intel.com> (raw)
In-Reply-To: <20170114004230.GA21035@apronin>
On Fri, Jan 13, 2017 at 04:42:30PM -0800, Andrey Pronin wrote:
> On Fri, Jan 13, 2017 at 05:28:57PM -0700, Jason Gunthorpe wrote:
> > On Fri, Jan 13, 2017 at 04:09:54PM -0800, Andrey Pronin wrote:
> > > Resetting TPM while processing a command may lead to issues
> > > on the next boot. Ensure that we don't have any ongoing
> > > commands, and that no further commands can be sent to the chip
> > > by unregistering the device in the shutdown handler.
> > > tpm_chip_unregister() waits for the completion of an ongoing
> > > command, if any, and then clears out chip->ops and unregisters
> > > sysfs entities.
> >
> > Unregistering in a shutdown handler seems very strange, it also waits
> > for userspace things, so I wonder if it could be problematic?
> >
> > Maybe just use
> >
> > down_write(&chip->ops_sem);
> > chip->ops = NULL;
> > up_write(&chip->ops_sem);
> >
> > In the shutdown handler?
>
> down_write(&chip->ops_sem) would still wait for completing the initiated
> writes, since tpm_write() in tpm-dev.c calls tpm_try_get_ops().
> Also, tpm-sysfs.c calls chip->ops directly, so sysfs should be
> unregistered first.
Why don't you fix the tpm-sysfs issue but rather misusing
tpm_chip_unregister?
/Jarkko
next prev parent reply other threads:[~2017-01-16 9:33 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-14 0:09 [PATCH] tpm/tpm_i2c_infineon: ensure no ongoing commands on shutdown Andrey Pronin
2017-01-14 0:09 ` Andrey Pronin
2017-01-14 0:28 ` Jason Gunthorpe
2017-01-14 0:28 ` Jason Gunthorpe
2017-01-14 0:42 ` Andrey Pronin
2017-01-16 9:33 ` Jarkko Sakkinen [this message]
2017-01-25 18:59 ` [tpmdd-devel] " Jarkko Sakkinen
2017-01-16 16:19 ` Jason Gunthorpe
2017-01-17 17:58 ` Andrey Pronin
2017-01-17 17:58 ` Andrey Pronin
2017-01-17 19:27 ` Jason Gunthorpe
2017-01-17 19:27 ` Jason Gunthorpe
2017-01-17 20:13 ` Andrey Pronin
2017-01-17 20:13 ` Andrey Pronin
2017-01-17 20:59 ` Jason Gunthorpe
2017-01-17 20:59 ` Jason Gunthorpe
2017-01-17 23:00 ` Andrey Pronin
2017-01-17 23:00 ` Andrey Pronin
2017-01-17 23:22 ` Jason Gunthorpe
2017-01-17 23:22 ` Jason Gunthorpe
2017-01-23 20:02 ` Andrey Pronin
2017-01-23 20:02 ` Andrey Pronin
2017-01-23 20:16 ` [tpmdd-devel] " Andrey Pronin
2017-01-23 20:39 ` Jason Gunthorpe
2017-01-23 20:39 ` Jason Gunthorpe
2017-01-23 22:19 ` Andrey Pronin
2017-01-23 22:57 ` Jason Gunthorpe
2017-01-23 22:57 ` Jason Gunthorpe
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