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Subject: Re: [PATCH V3 8/9] tracing: Add osnoise tracer
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     linux-kernel@vger.kernel.org, Phil Auld <pauld@redhat.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Kate Carcia <kcarcia@redhat.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Alexandre Chartre <alexandre.chartre@oracle.com>,
        Clark Willaims <williams@redhat.com>,
        John Kacur <jkacur@redhat.com>,
        Juri Lelli <juri.lelli@redhat.com>, linux-doc@vger.kernel.org
References: <cover.1621024265.git.bristot@redhat.com>
 <bd09a2be9cd0cecee86374dbb49235dd2ef9d750.1621024265.git.bristot@redhat.com>
 <20210604172803.527aa070@oasis.local.home>
 <abf38ca3-3c14-c00a-ff74-f1a75e3ec2e5@redhat.com>
 <20210608133946.52eb7859@oasis.local.home>
From:   Daniel Bristot de Oliveira <bristot@redhat.com>
Message-ID: <0db868d6-2f16-d59e-0eb2-5c55709b4741@redhat.com>
Date:   Tue, 8 Jun 2021 21:33:31 +0200
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On 6/8/21 7:39 PM, Steven Rostedt wrote:
>> I created a "bool tainted" variable, that is set true if any problem with time()
>> related functions happen. I will pr_warn that there is a problem on _start(),
>> but also print this info at the top of the tracer header, so it is clear also
>> from the trace output.
>>
>> Thoughts?
>>
> Or perhaps have that pr_err() actually be written into the trace buffer?
> 
> You can use
> 
> 	trace_array_printk_buf(tr->array_buffer.buffer, _THIS_IP_, "string");
> 
> without it triggering that nasty trace_printk() notice ;-)

cool! I created a function osnoise_taint(char *msg) that prints the msg using
trace_array_printk_buf. I am using it instead of all pr_warn that could take
place inside osnoise regular operation.

I am still placing the note in the header, just in case we miss the message in
the log.

-- Daniel

> -- Steve
>