Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent

From	Steven Rostedt <rostedt@goodmis.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent
Date	2016-10-19 21:30 +0200
Message-ID	<su4IN-5Ai-7@gated-at.bofh.it> (permalink)
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On Wed, 19 Oct 2016 15:05:48 -0300
Arnaldo Carvalho de Melo <acme@kernel.org> wrote:

> Some are the compiler not grokking logic where the compiler gets
> confused with logic that tests one variable to use another and thinks it
> is using garbage (uninitialized stuff), I tried to follow the logic and
> I think it got slightly more confused than me, as I _think_ its not a
> problem, but the one on the case entry for
> 
>   OLD_RINGBUF_TYPE_TIME_EXTEND
> 
> in old_update_pointers() looks like a bug, unless some macro magic is
> taking place that updates that 'lenght' variable.
> 
> Rostedt, that -O2 unleashed some warnings, please check, I'll defer
> applying those patches till it doesn't show these warnings, i.e. till
> other patches fixing these issues or simply silencing the compiler with
> a harmless init gets submitted,
> 
> Thanks,

Note, that code is for the first version of the ftrace ring buffer that
got changed around 2.6.32 I believe. And since trace-cmd was the only
tool that directly looked at the code, I was able to "break" abi and
update trace-cmd to have a new version. So that code isn't even used
anywhere on newer kernels.

That said, could you add in the case statement for
OLD_RINGBUF_TYPE_TIME_EXTEND:

	length = 0;

I think that should be fine.

-- Steve

Thread

[PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent Honggyu Kim <hong.gyu.kim@lge.com> - 2016-10-17 16:20 +0200
  [PATCH 2/3] tools lib traceevent: Check the return value of asprintf Honggyu Kim <hong.gyu.kim@lge.com> - 2016-10-17 16:20 +0200
    Re: [PATCH 2/3] tools lib traceevent: Check the return value of  asprintf Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-10-18 20:00 +0200
      Re: [PATCH 2/3] tools lib traceevent: Check the return value of  asprintf Namhyung Kim <namhyung@kernel.org> - 2016-10-19 02:30 +0200
  [PATCH 3/3] tools lib traceevent: Fix to set uninitialized variables Honggyu Kim <hong.gyu.kim@lge.com> - 2016-10-17 16:20 +0200
    Re: [PATCH 3/3] tools lib traceevent: Fix to set uninitialized  variables Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-10-18 20:10 +0200
  Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent Namhyung Kim <namhyung@kernel.org> - 2016-10-18 04:10 +0200
    Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent Steven Rostedt <rostedt@goodmis.org> - 2016-10-18 17:40 +0200
      Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-10-19 19:50 +0200
        Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-10-19 20:10 +0200
          Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-10-19 20:10 +0200
            Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent Steven Rostedt <rostedt@goodmis.org> - 2016-10-19 21:30 +0200
          Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent Steven Rostedt <rostedt@goodmis.org> - 2016-10-19 21:30 +0200
        Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent Steven Rostedt <rostedt@goodmis.org> - 2016-10-19 20:30 +0200

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