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From:   Kees Cook <keescook@chromium.org>
Date:   Mon, 17 Sep 2018 07:54:49 -0700
Message-ID: <CAGXu5jLkE+mZkVSFPeOq75im0Kozm+NzfqL9CD-OMe7b7=3O5g@mail.gmail.com>
Subject: Re: [PATCH 2/6] pstore: Add event tracing support
To:     Joel Fernandes <joel@joelfernandes.org>
Cc:     Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>,
        Laura Abbott <labbott@redhat.com>,
        Anton Vorontsov <anton@enomsg.org>,
        Rob Herring <robh+dt@kernel.org>, devicetree@vger.kernel.org,
        Colin Cross <ccross@android.com>,
        Jason Baron <jbaron@akamai.com>,
        Tony Luck <tony.luck@intel.com>, Arnd Bergmann <arnd@arndb.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Joe Perches <joe@perches.com>,
        Jim Cromie <jim.cromie@gmail.com>,
        Rajendra Nayak <rnayak@codeaurora.org>,
        Vivek Gautam <vivek.gautam@codeaurora.org>,
        Sibi Sankar <sibis@codeaurora.org>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-arm-msm@vger.kernel.org,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        Tom Zanussi <tom.zanussi@linux.intel.com>,
        Prasad Sodagudi <psodagud@codeaurora.org>,
        tsoni@codeaurora.org, Bryan Huntsman <bryanh@codeaurora.org>,
        Tingwei Zhang <tingwei@codeaurora.org>,
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On Sun, Sep 16, 2018 at 6:55 AM, Joel Fernandes <joel@joelfernandes.org> wrote:
> On Sun, Sep 16, 2018, 12:08 AM Sai Prakash Ranjan
> <saiprakash.ranjan@codeaurora.org> wrote:
>>
>> On 9/9/2018 1:57 AM, Sai Prakash Ranjan wrote:
>> > Currently pstore has function trace support which can be
>> > used to get the function call chain with limited data.
>> > Event tracing has extra data which is useful to debug wide
>> > variety of issues and is heavily used across the kernel.
>> >
>> > Adding this support to pstore can be very helpful to debug
>> > different subsystems since almost all of them have trace
>> > events already available. And also it is useful to debug
>> > unknown resets or crashes since we can get lot more info
>> > from event tracing by viewing the last occurred events.
>>
>> Anyone here?
>
> Sorry for the top post. I've been wanting to do this as well for some time.
> It's quite useful. I am out of office this week and away from work machine.
> I will take a look at your patches next week once I'm back at work. Thanks.

If Steven agrees this shouldn't live in ftrace directly and Joel
reviews these patches, I think it should be fine. I'm travelling, but
I can review it hopefully later this week.

-Kees

-- 
Kees Cook
Pixel Security