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Date: Wed, 6 Nov 2024 17:30:23 -0500
From: Steven Rostedt <rostedt@goodmis.org>
To: Marco Elver <elver@google.com>
Cc: Kees Cook <keescook@chromium.org>, Masami Hiramatsu
 <mhiramat@kernel.org>, Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
 Andrew Morton <akpm@linux-foundation.org>, Oleg Nesterov <oleg@redhat.com>,
 linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Dmitry
 Vyukov <dvyukov@google.com>, kasan-dev@googlegroups.com
Subject: Re: [PATCH] tracing: Add task_prctl_unknown tracepoint
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On Wed, 6 Nov 2024 22:59:25 +0100
Marco Elver <elver@google.com> wrote:

> On Wed, 6 Nov 2024 at 22:23, Steven Rostedt <rostedt@goodmis.org> wrote:
> ...
> > > That's pretty much it. I've attached my kernel config just in case I
> > > missed something.  
> >
> > OK, it's because you are using trace_pipe (which by the way should not be
> > used for anything serious). The read of trace_pipe flushes the buffer
> > before the task is scheduled out and the comm saved, so it prints the
> > "<...>". If you instead do the cat of trace_pipe *after* running the
> > command, you'll see the comm.
> >
> > So this is just because you are using the obsolete trace_pipe.  
> 
> I see, thanks for clarifying.  I always felt for quick testing it
> serves its purpose - anything equally simple you recommend for testing
> but doesn't suffer from this problem?

You can run trace-cmd, or cat trace after the run.

-- Steve