From: Hao Wu <hao.wu@rubrik.com>
To: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Shrihari Kalkar <shrihari.kalkar@rubrik.com>,
Seungyeop Han <seungyeop.han@rubrik.com>,
Anish Jhaveri <anish.jhaveri@rubrik.com>,
peterhuewe@gmx.de, jgg@ziepe.ca, linux-integrity@vger.kernel.org,
Paul Menzel <pmenzel@molgen.mpg.de>,
Ken Goldman <kgold@linux.ibm.com>,
zohar@linux.vnet.ibm.com, why2jjj.linux@gmail.com,
Hamza Attak <hamza@hpe.com>,
gregkh@linuxfoundation.org, arnd@arndb.de,
Nayna <nayna@linux.vnet.ibm.com>,
James.Bottomley@hansenpartnership.com
Subject: Re: [PATCH v2] tpm: fix ATMEL TPM crash caused by too frequent queries
Date: Thu, 8 Jul 2021 21:43:01 -0700 [thread overview]
Message-ID: <3019504F-E18A-42C8-BB4E-54F3FB4636D2@rubrik.com> (raw)
In-Reply-To: <20210707211053.obfqcfq42cqlamns@kernel.org>
> On Jul 7, 2021, at 2:10 PM, Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> On Wed, Jul 07, 2021 at 11:28:35AM -0700, Hao Wu wrote:
>>> On Jul 7, 2021, at 2:24 AM, Jarkko Sakkinen <jarkko@kernel.org> wrote:
>>>
>>> On Tue, Jul 06, 2021 at 09:31:35PM -0700, Hao Wu wrote:
>>>> Since kernel 4.14, there was a commit (9f3fc7bcddcb)
>
> BTW, please remove this. You have a fixes tag.
>
>>>> fixed the TPM sleep logic from msleep to usleep_range,
>>>> so that the TPM sleeps exactly with TPM_TIMEOUT (=5ms) afterward.
>>>> Before that fix, msleep(5) actually sleeps for around 15ms.
>>>
>>> What is TPM sleep logic?
>> It is about the commit metnioned in the description
>> `tpm: replace msleep() with usleep_range() in TPM 1.2/2.0 generic drivers`
>> https://github.com/torvalds/linux/commit/9f3fc7bcddcb51234e23494531f93ab60475e1c3
>
> What you should do is to explain in simple terms the unwanted behaviour
> that you are observing, and also, *when* you observe it. E.g. does this
> happen when you use /dev/tpm0, or is it visible already in klog at boot
> time. And also: does it occur for anything you put to /dev/tpm0, or is
> the bug triggering for some particular TPM commands.
>
> You also need to have information what kind of Atmel chip triggers the
> bug. I'd presume that you have access to a machine with such chip?
>
> When you get all that figured out, you should explain how you change
> the existing behaviour, and why it makes sense. E.g. if you fixup
> timeouts, please just tell how'd you end up choosing the values that
> you picked.
>
> E.g. the rationale for that could come from testing and finding the "sweet
> spot", or perhaps the reason could be that old values worked, new ones
> don't.
>
> Especially in bug fixes the reasoning is *at least* as important as the
> the code change itself because I need to know what is going on.
>
> /Jarkko
Thanks Jarkko for pointing the direction! I have updated the description
and sent a new revision.
Hao
next prev parent reply other threads:[~2021-07-09 4:43 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-20 23:18 [PATCH] Fix Atmel TPM crash caused by too frequent queries Hao Wu
2021-06-23 13:35 ` Jarkko Sakkinen
2021-06-24 5:49 ` Hao Wu
2021-06-29 20:06 ` Jarkko Sakkinen
2021-06-30 4:27 ` Hao Wu
2021-06-24 5:33 ` Hao Wu
2021-06-29 20:07 ` Jarkko Sakkinen
2021-06-30 4:22 ` [PATCH] tpm: fix ATMEL " Hao Wu
2021-07-02 6:35 ` Jarkko Sakkinen
2021-07-02 7:12 ` Greg KH
2021-07-02 7:33 ` Hao Wu
2021-07-02 7:35 ` Hao Wu
2021-07-02 7:45 ` Jarkko Sakkinen
2021-07-02 7:59 ` Hao Wu
2021-07-02 8:42 ` Jarkko Sakkinen
2021-07-02 11:57 ` Jarkko Sakkinen
2021-07-02 19:16 ` Hao Wu
2021-07-05 5:19 ` Jarkko Sakkinen
2021-07-05 5:29 ` Hao Wu
2021-07-04 0:07 ` Hao Wu
2021-07-05 7:15 ` Jarkko Sakkinen
2021-07-05 23:09 ` Hao Wu
2021-07-06 12:34 ` Mimi Zohar
2021-07-07 4:18 ` Hao Wu
2021-07-07 4:34 ` Hao Wu
2021-07-07 4:31 ` [PATCH v2] " Hao Wu
2021-07-07 9:24 ` Jarkko Sakkinen
2021-07-07 18:28 ` Hao Wu
2021-07-07 21:10 ` Jarkko Sakkinen
2021-07-09 4:43 ` Hao Wu [this message]
2021-07-09 4:40 ` [PATCH v2] tpm: fix Atmel " Hao Wu
2021-07-09 17:47 ` Jarkko Sakkinen
2021-07-09 19:23 ` Hao Wu
2021-07-11 7:37 ` Hao Wu
2021-07-16 5:30 ` Hao Wu
2021-07-11 7:51 ` [PATCH v3] " Hao Wu
2021-07-27 2:46 ` Jarkko Sakkinen
2021-07-27 3:40 ` Hao Wu
2021-08-14 22:25 ` [PATCH v4] " Hao Wu
2021-08-26 5:38 ` Hao Wu
2021-08-26 16:24 ` Jarkko Sakkinen
2021-08-27 0:35 ` Hao Wu
2021-09-04 21:14 ` Hao Wu
2021-09-04 23:15 ` Hao Wu
2021-09-05 3:51 ` [PATCH v5] " Hao Wu
2021-09-07 17:43 ` Jarkko Sakkinen
2021-09-08 8:33 ` Hao Wu
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