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From: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
To: Stephen Boyd <swboyd@chromium.org>
Cc: Peter Huewe <peterhuewe@gmx.de>,
	linux-kernel@vger.kernel.org, Jason Gunthorpe <jgg@ziepe.ca>,
	Arnd Bergmann <arnd@arndb.de>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-integrity@vger.kernel.org,
	Andrey Pronin <apronin@chromium.org>,
	Duncan Laurie <dlaurie@chromium.org>,
	Guenter Roeck <groeck@chromium.org>,
	Herbert Xu <herbert@gondor.apana.org.au>
Subject: Re: [PATCH v2 1/6] hwrng: core: Freeze khwrng thread during suspend
Date: Fri, 2 Aug 2019 23:22:09 +0300	[thread overview]
Message-ID: <20190802202209.2jzeosacc66mtnpr@linux.intel.com> (raw)
In-Reply-To: <20190716224518.62556-2-swboyd@chromium.org>

On Tue, Jul 16, 2019 at 03:45:13PM -0700, Stephen Boyd wrote:
> The hwrng_fill() function can run while devices are suspending and
> resuming. If the hwrng is behind a bus such as i2c or SPI and that bus
> is suspended, the hwrng may hang the bus while attempting to add some
> randomness. It's been observed on ChromeOS devices with suspend-to-idle
> (s2idle) and an i2c based hwrng that this kthread may run and ask the
> hwrng device for randomness before the i2c bus has been resumed.
> 
> Let's make this kthread freezable so that we don't try to touch the
> hwrng during suspend/resume. This ensures that we can't cause the hwrng
> backing driver to get into a bad state because the device is guaranteed
> to be resumed before the hwrng kthread is thawed.
> 
> Cc: Andrey Pronin <apronin@chromium.org>
> Cc: Herbert Xu <herbert@gondor.apana.org.au>
> Cc: Duncan Laurie <dlaurie@chromium.org>
> Signed-off-by: Stephen Boyd <swboyd@chromium.org>

This does not need a fixes tag?

/Jarkko

  parent reply	other threads:[~2019-08-02 20:22 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-16 22:45 [PATCH v2 0/6] tpm: Add driver for cr50 Stephen Boyd
2019-07-16 22:45 ` [PATCH v2 1/6] hwrng: core: Freeze khwrng thread during suspend Stephen Boyd
2019-07-17  1:43   ` Herbert Xu
2019-07-17 16:36     ` Stephen Boyd
2019-07-17 11:39   ` Jason Gunthorpe
2019-07-17 16:42     ` Stephen Boyd
2019-07-17 16:50       ` Jason Gunthorpe
2019-07-17 17:03         ` Stephen Boyd
2019-08-02 22:50           ` Stephen Boyd
2019-08-16 15:56             ` Alexander Steffen
2019-08-16 23:55               ` Jarkko Sakkinen
2019-08-02 20:22   ` Jarkko Sakkinen [this message]
2019-08-02 23:18     ` Stephen Boyd
2019-07-16 22:45 ` [PATCH v2 2/6] tpm_tis_core: add optional max xfer size check Stephen Boyd
2019-07-16 22:45 ` [PATCH v2 3/6] tpm_tis_spi: add max xfer size Stephen Boyd
2019-07-17  8:07   ` Alexander Steffen
2019-07-17 18:19     ` Stephen Boyd
2019-07-16 22:45 ` [PATCH v2 4/6] dt-bindings: tpm: document properties for cr50 Stephen Boyd
2019-07-16 22:45 ` [PATCH v2 5/6] tpm: add driver for cr50 on SPI Stephen Boyd
2019-07-17 12:00   ` Alexander Steffen
2019-07-17 12:25     ` Jason Gunthorpe
2019-07-17 16:49       ` Stephen Boyd
2019-07-17 16:56         ` Jason Gunthorpe
2019-07-17 17:05           ` Stephen Boyd
2019-07-17 17:12             ` Jason Gunthorpe
2019-07-17 17:22               ` Stephen Boyd
2019-07-17 17:25                 ` Jason Gunthorpe
2019-07-17 18:21                   ` Stephen Boyd
2019-07-17 18:30                     ` Guenter Roeck
2019-07-17 18:36                       ` Jason Gunthorpe
2019-07-17 19:57     ` Stephen Boyd
2019-07-17 21:38       ` Stephen Boyd
2019-07-17 22:17         ` Stephen Boyd
2019-07-18 16:47         ` Alexander Steffen
2019-07-18 18:11           ` Stephen Boyd
2019-07-19  7:53             ` Alexander Steffen
2019-08-01 16:02               ` Stephen Boyd
2019-08-02 15:21                 ` Jarkko Sakkinen
2019-08-02 18:03                   ` Stephen Boyd
2019-08-02 19:43                 ` Jarkko Sakkinen
2019-07-18 16:47       ` Alexander Steffen
2019-07-18 18:07         ` Stephen Boyd
2019-07-19  7:51           ` Alexander Steffen
2019-08-02 20:43         ` Jarkko Sakkinen
2019-08-02 22:32           ` Stephen Boyd
2019-08-02 20:41     ` Jarkko Sakkinen
2019-07-16 22:45 ` [PATCH v2 6/6] tpm: Add driver for cr50 on I2C Stephen Boyd
2019-07-17 15:19   ` Alexander Steffen
2019-08-05 23:52     ` Stephen Boyd
2019-08-02 20:44   ` Jarkko Sakkinen

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