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Date:   Sun, 1 Mar 2020 13:20:38 -0500
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     Andy Lutomirski <luto@amacapital.net>,
        Peter Zijlstra <peterz@infradead.org>,
        Andy Lutomirski <luto@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>, x86@kernel.org,
        Brian Gerst <brgerst@gmail.com>,
        Juergen Gross <JGross@suse.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Arnd Bergmann <arnd@arndb.de>,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [patch 4/8] x86/entry: Move irq tracing on syscall entry to
 C-code
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On Sun, 01 Mar 2020 16:21:15 +0100
Thomas Gleixner <tglx@linutronix.de> wrote:

> Andy Lutomirski <luto@amacapital.net> writes:
> >> On Mar 1, 2020, at 2:16 AM, Thomas Gleixner <tglx@linutronix.de> wrote:
> >> Ok, but for the time being anything before/after CONTEXT_KERNEL is unsafe
> >> except trace_hardirq_off/on() as those trace functions do not allow to
> >> attach anything AFAICT.  
> >
> > Can you point to whatever makes those particular functions special?  I
> > failed to follow the macro maze.  
> 
> Those are not tracepoints and not going through the macro maze. See
> kernel/trace/trace_preemptirq.c

For the latency tracing, they do call into the tracing infrastructure,
not just lockdep. And Joel Fernandez did try to make these into trace
events as well.

-- Steve