From: Jarkko Sakkinen <jarkko@kernel.org>
To: Hao Wu <hao.wu@rubrik.com>,
shrihari.kalkar@rubrik.com, seungyeop.han@rubrik.com,
anish.jhaveri@rubrik.com, peterhuewe@gmx.de, jgg@ziepe.ca,
linux-integrity@vger.kernel.org, pmenzel@molgen.mpg.de,
kgold@linux.ibm.com, zohar@linux.vnet.ibm.com,
why2jjj.linux@gmail.com, hamza@hpe.com,
gregkh@linuxfoundation.org, arnd@arndb.de,
nayna@linux.vnet.ibm.com, James.Bottomley@hansenpartnership.com
Subject: Re: [PATCH v6] tpm: fix Atmel TPM crash caused by too frequent queries
Date: Thu, 09 Sep 2021 17:08:26 +0300 [thread overview]
Message-ID: <3f3d10544a3f83e4a940896abeb80da948cba827.camel@kernel.org> (raw)
In-Reply-To: <20210908092606.96115-1-hao.wu@rubrik.com>
On Wed, 2021-09-08 at 02:26 -0700, Hao Wu wrote:
> The Atmel TPM 1.2 chips crash with error
> `tpm_try_transmit: send(): error -62` since kernel 4.14.
> It is observed from the kernel log after running `tpm_sealdata -z`.
> The error thrown from the command is as follows
> ```
> $ tpm_sealdata -z
> Tspi_Key_LoadKey failed: 0x00001087 - layer=tddl,
> code=0087 (135), I/O error
> ```
>
> The issue was reproduced with the following Atmel TPM chip:
> ```
> $ tpm_version
> T0 TPM 1.2 Version Info:
> Chip Version: 1.2.66.1
> Spec Level: 2
> Errata Revision: 3
> TPM Vendor ID: ATML
> TPM Version: 01010000
> Manufacturer Info: 41544d4c
> ```
>
> The root cause of the issue is due to the TPM calls to msleep()
> were replaced with usleep_range() [1], which reduces
> the actual timeout. Via experiments, it is observed that
> the original msleep(5) actually sleeps for 15ms.
> Because of a known timeout issue in Atmel TPM 1.2 chip,
> the shorter timeout than 15ms can cause the error described above.
>
> A few further changes in kernel 4.16 [2] and 4.18 [3, 4] further
> reduced the timeout to less than 1ms. With experiments,
> the problematic timeout in the latest kernel is the one
> for `wait_for_tpm_stat`.
>
> To fix it, the patch reverts the timeout of `wait_for_tpm_stat`
> to 15ms for all Atmel TPM 1.2 chips, but leave it untouched
> for Ateml TPM 2.0 chip, and chips from other vendors.
> As explained above, the chosen 15ms timeout is
> the actual timeout before this issue introduced,
> thus the old value is used here.
> Particularly, TPM_ATML_TIMEOUT_WAIT_STAT_MIN is set to 14700us,
> TPM_ATML_TIMEOUT_WAIT_STAT_MIN is set to 15000us according to
> the existing TPM_TIMEOUT_RANGE_US (300us).
> The fixed has been tested in the system with the affected Atmel chip
> with no issues observed after boot up.
>
> References:
> [1] 9f3fc7bcddcb tpm: replace msleep() with usleep_range() in TPM
> 1.2/2.0 generic drivers
> [2] cf151a9a44d5 tpm: reduce tpm polling delay in tpm_tis_core
> [3] 59f5a6b07f64 tpm: reduce poll sleep time in tpm_transmit()
> [4] 424eaf910c32 tpm: reduce polling time to usecs for even finer
> granularity
>
> Fixes: 9f3fc7bcddcb ("tpm: replace msleep() with usleep_range() in TPM 1.2/2.0 generic drivers")
> Link: https://patchwork.kernel.org/project/linux-integrity/patch/20200926223150.109645-1-hao.wu@rubrik.com/
> Signed-off-by: Hao Wu <hao.wu@rubrik.com>
Thanks!
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
/Jarkko
next prev parent reply other threads:[~2021-09-09 14:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-08 9:26 [PATCH v6] tpm: fix Atmel TPM crash caused by too frequent queries Hao Wu
2021-09-09 14:08 ` Jarkko Sakkinen [this message]
2021-09-09 17:32 ` Hao Wu
-- strict thread matches above, loose matches on Subject: below --
2021-09-08 9:16 Hao Wu
2021-09-08 9:22 ` Hao Wu
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