linux-kernel - Re: [PATCH v3 0/8] pstore: Improve performance of ftrace backend with ramoops

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Message-ID: <CAGXu5jLPB7=j=qaeOD92MmXBXP657vKriNUSo71TiyOWbM3anQ@mail.gmail.com>
Date:   Tue, 15 Nov 2016 14:14:49 -0800
From:   Kees Cook <keescook@...omium.org>
To:     Joel Fernandes <joelaf@...gle.com>
Cc:     Anton Vorontsov <anton@...msg.org>,
        Colin Cross <ccross@...roid.com>,
        Tony Luck <tony.luck@...el.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 0/8] pstore: Improve performance of ftrace backend with ramoops

On Tue, Nov 15, 2016 at 2:06 PM, Joel Fernandes <joelaf@...gle.com> wrote:
> Hi Kees,
>
> On Tue, Nov 15, 2016 at 1:36 PM, Kees Cook <keescook@...omium.org> wrote:
>> On Tue, Nov 15, 2016 at 11:55 AM, Joel Fernandes <joelaf@...gle.com> wrote:
>>> Hi Kees,
>>>
>>> On Fri, Nov 11, 2016 at 2:21 PM, Kees Cook <keescook@...omium.org> wrote:
>>>> Hi Joel,
>>>>
>>>> I've reorganized a bunch of the logic here. Since pstore is going to need
>>>> the init_przs() logic for multiple pmsg przs, I wanted to get this in and
>>>> make sure I was happy with how it looks. I figured this would reduce our
>>>> round-trip time on reviews. :)
>>>>
>>>> Can you test this series and verify that it works as you're expecting? I've
>>>> validated some basic behavior already, but don't have a good test-case for
>>>> ftrace. What commands do you actually use for testing ftrace? I'd like to
>>>> add something to my local tests.
>>>
>>> I normally do the following:
>>>
>>> dd if=/dev/urandom | pv | dd of=/dev/null
>>>
>>> and in parallel, I do a:
>>> echo 1 > /sys/kernel/debug/pstore/record_ftrace
>>>
>>> and then check the throughput; and then reboot the system and do a
>>> read out of /sys/fs/pstore/ ftrace file.
>>
>> Cool. Does something normally parse these? Lots of kernel addresses is
>> all I see. ;)
>>
>
> It should print symbol names if KALLSYMS is working properly as it
> uses %pf (in pstore_ftrace_seq_show function).

Hrm. No such luck for me, but it's clearly using pstore correctly, so
I'm satisfied things are working along that path. :)

-Kees

-- 
Kees Cook
Nexus Security