From: Herbert Xu <herbert@gondor.apana.org.au>
To: Stephen Boyd <swboyd@chromium.org>
Cc: Peter Huewe <peterhuewe@gmx.de>,
Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
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>
Subject: Re: [PATCH v2 1/6] hwrng: core: Freeze khwrng thread during suspend
Date: Wed, 17 Jul 2019 09:43:59 +0800 [thread overview]
Message-ID: <20190717014359.5xcnubpmazl3vqg5@gondor.apana.org.au> (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>
> ---
> drivers/char/hw_random/core.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
Do you want this to go through the crypto tree? If so you need
to cc the linux-crypto mailing list.
Thanks,
--
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
next prev parent reply other threads:[~2019-07-17 1:44 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 [this message]
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
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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