Messages in this thread | | | Date | Wed, 19 Oct 2016 15:21:56 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH 1/3] tools lib traceevent: Add -O2 option to traceevent |
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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
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