Subject: Re: [PATCH 0/7] selftests/ftrace: Some improvements of ftracetest
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Shuah Khan <shuah@kernel.org>, Masami Hiramatsu <mhiramat@kernel.org>,
        linux-kselftest@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
        linux-kernel@vger.kernel.org, Shuah Khan <shuahkh@osg.samsung.com>
References: <149551934796.30231.12544755801380678045.stgit@devbox>
 <4b0b2ac8-dfba-abd9-3dba-bbe73c22f79f@kernel.org>
 <20170607185628.452a11a1@gandalf.local.home>
 <8f974157-c2e5-9b39-c55b-b637d6e7814f@osg.samsung.com>
 <20170608133743.4720e2bc@gandalf.local.home>
 <8bcf5a87-812a-6ceb-7fa4-ea2d33d4e717@osg.samsung.com>
 <20170608170844.134e1158@gandalf.local.home>
 <9a2b4e46-a545-b862-2517-472f364a68b3@osg.samsung.com>
 <20170608172627.3dab319e@gandalf.local.home>
 <9be74d50-aee5-4771-a62c-e04156176263@osg.samsung.com>
 <20170608173946.7c9308f2@gandalf.local.home>
From: Shuah Khan <shuahkh@osg.samsung.com>
Message-ID: <052a7347-be6e-42e2-de5e-6f5849fa1e8e@osg.samsung.com>
Date: Thu, 8 Jun 2017 15:44:08 -0600
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On 06/08/2017 03:39 PM, Steven Rostedt wrote:
> On Thu, 8 Jun 2017 15:33:39 -0600
> Shuah Khan <shuahkh@osg.samsung.com> wrote:
> 
> 
>>> Note, when a bug is found, we do add the reproducer to ftracetest. So
>>> depending on whether you have the latest stable, or the stable has a
>>> fix, ftracetest can cause the machine to crash on older releases.  
>>
>> Yeah - that could be problem, I would worry more if ftracetest can be run
>> as a non-root user. As ftracetest is intrusive in nature just like the timer
>> tests, we could say user needs to be aware.
>>
>> If the outcome isn't desirable, we could run ftracetest conditionally as
>> a last resort. I think it is important for it to be run as part of kselftest
>> suite run.
> 
> Well, I wouldn't worry too much. It shouldn't do any damage. And
> anything that can trigger a bug in previous kernels should be
> backported as well to the stable releases. Everyone runs the latest
> stable kernels, right?
> 
> Also, did you see my reply about having the right config? You have
> HIST_TRIGGERS undefined but yet the histogram trigger tests all pass in
> your report.

I did see that one. Didn't get a chance to look at that yet. Do you expect
the tests to be skipped in this case? Could it be that tests aren't run?
I will look at this and let you know what I find on my test system.

> 
> One more thing, is this 100% reproducible. That is, does it always fail?
> 
Failed the two times I tried.

thanks,
-- Shuah