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From: Jason Gunthorpe <jgunthorpe-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
To: Andrey Pronin <apronin-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	semenzato-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org,
	tpmdd-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org,
	groeck-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org
Subject: Re: [PATCH] tpm/tpm_i2c_infineon: ensure no ongoing commands on shutdown
Date: Fri, 13 Jan 2017 17:28:57 -0700	[thread overview]
Message-ID: <20170114002857.GA5851@obsidianresearch.com> (raw)
In-Reply-To: <20170114000954.17728-1-apronin-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>

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?

Jason

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WARNING: multiple messages have this Message-ID (diff)
From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Andrey Pronin <apronin@chromium.org>
Cc: Peter Huewe <peterhuewe@gmx.de>,
	Marcel Selhorst <tpmdd@selhorst.net>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
	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: Fri, 13 Jan 2017 17:28:57 -0700	[thread overview]
Message-ID: <20170114002857.GA5851@obsidianresearch.com> (raw)
In-Reply-To: <20170114000954.17728-1-apronin@chromium.org>

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?

Jason

  parent reply	other threads:[~2017-01-14  0:28 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
     [not found] ` <20170114000954.17728-1-apronin-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>
2017-01-14  0:28   ` Jason Gunthorpe [this message]
2017-01-14  0:28     ` Jason Gunthorpe
2017-01-14  0:42     ` Andrey Pronin
2017-01-16  9:33       ` Jarkko Sakkinen
2017-01-25 18:59         ` [tpmdd-devel] " Jarkko Sakkinen
2017-01-16 16:19       ` Jason Gunthorpe
     [not found]         ` <20170116161919.GA20238-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
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
     [not found]               ` <20170117192728.GF27528-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
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
     [not found]                     ` <20170117205933.GA9604-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
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
     [not found]                           ` <20170117232207.GA12127-ePGOBjL8dl3ta4EC/59zMFaTQe2KTcn/@public.gmane.org>
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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