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From:   Wei Wang <wvw@google.com>
Date:   Tue, 24 Apr 2018 21:32:26 +0000
Message-ID: <CAGXk5yo0FoBYdtbsg9b+ZqTuNu5wKNQokzHbu=33YF93ombgng@mail.gmail.com>
Subject: Re: [PATCH] do not call trace_printk on non-debug build
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     gregkh@linuxfoundation.org, Wei Wang <wei.vince.wang@gmail.com>,
        Ingo Molnar <mingo@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Crt Mori <cmo@melexis.com>,
        Alexei Starovoitov <ast@kernel.org>,
        Randy Dunlap <rdunlap@infradead.org>,
        linux-kernel@vger.kernel.org, Joe Perches <joe@perches.com>
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I have seen case when LLVM appends postfix to most function names, causing
func such as tracing_mark_write becomes tracing_mark_write.XXX which messed
all post-processing.
Also I think this is a typo?
https://lkml.org/lkml/2018/4/24/1176
On Tue, Apr 24, 2018 at 1:48 PM Steven Rostedt <rostedt@goodmis.org> wrote:

> On Tue, 24 Apr 2018 16:45:05 -0400
> Steven Rostedt <rostedt@goodmis.org> wrote:

> > On Tue, 24 Apr 2018 20:39:27 +0000
> > Wei Wang <wvw@google.com> wrote:
> >
> > > The config is not something new and it is controlling pr_debug and
> > > pr_devel, so might not be too annoying, IMHO. But I agree this is not
a
> > > problem from us but from abusers.
> >
> > And is the reason I never use pr_debug() and pr_devel().
> >

> Which reminds me, I need to replace pr_debug() to pr_info() for this
> line:

>    pr_debug("syscall %s metadata not mapped, disabling ftrace event\n",

> In trace_syscalls.c (I didn't add that), as a different commit that
> changed syscall names for x86 caused all syscall tracepoints to
> disappear. And if this was pr_info() and not pr_debug() the one that
> made the change would have noticed his change had impact someplace else.

> -- Steve