linux-kernel - Re: [PATCH 01/15] taint: add module firmware crash taint support

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Message-ID: <b48a2894-f67c-03d1-502a-9e7e7d4435ff@infradead.org>
Date:   Sat, 9 May 2020 19:19:46 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Luis Chamberlain <mcgrof@...nel.org>,
        Rafael Aquini <aquini@...hat.com>
Cc:     jeyu@...nel.org, akpm@...ux-foundation.org, arnd@...db.de,
        rostedt@...dmis.org, mingo@...hat.com, cai@....pw,
        dyoung@...hat.com, bhe@...hat.com, peterz@...radead.org,
        tglx@...utronix.de, gpiccoli@...onical.com, pmladek@...e.com,
        tiwai@...e.de, schlad@...e.de, andriy.shevchenko@...ux.intel.com,
        keescook@...omium.org, daniel.vetter@...ll.ch, will@...nel.org,
        mchehab+samsung@...nel.org, kvalo@...eaurora.org,
        davem@...emloft.net, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 01/15] taint: add module firmware crash taint support

On 5/9/20 9:46 AM, Luis Chamberlain wrote:
> On Sat, May 09, 2020 at 11:18:29AM -0400, Rafael Aquini wrote:
>> We are still missing the documentation bits for this
>> new flag, though.
> 
> Ah yeah sorry about that.
> 
>> How about having a blurb similar to:
>>
>> diff --git a/Documentation/admin-guide/tainted-kernels.rst b/Documentation/admin-guide/tainted-kernels.rst
>> index 71e9184a9079..5c6a9e2478b0 100644
>> --- a/Documentation/admin-guide/tainted-kernels.rst
>> +++ b/Documentation/admin-guide/tainted-kernels.rst
>> @@ -100,6 +100,7 @@ Bit  Log  Number  Reason that got the kernel tainted
>>   15  _/K   32768  kernel has been live patched
>>   16  _/X   65536  auxiliary taint, defined for and used by distros
>>   17  _/T  131072  kernel was built with the struct randomization plugin
>> + 18  _/Q  262144  driver firmware crash annotation
>>  ===  ===  ======  ========================================================
>>
>>  Note: The character ``_`` is representing a blank in this table to make reading
>> @@ -162,3 +163,7 @@ More detailed explanation for tainting
>>       produce extremely unusual kernel structure layouts (even performance
>>       pathological ones), which is important to know when debugging. Set at
>>       build time.
>> +
>> + 18) ``Q`` Device drivers might annotate the kernel with this taint, in cases
>> +     their firmware might have crashed leaving the driver in a crippled and
>> +     potentially useless state.
> 
> Sure, I'll modify it a bit to add the use case to help with support
> issues, ie, to help rule out firmware issues.

Please also update tools/debugging/kernel-chktaint.

> I'm starting to think that to make this even more usesul later we may
> want to add a uevent to add_taint() so that userspace can decide to look
> into this, ignore it, or report something to the user, say on their
> desktop.

thanks.
-- 
~Randy