Re: FTRACE_WARN_ON((rec->flags & ~FTRACE_FL_MASK) == 0))

From: Dave Jones
Date: Wed Aug 28 2013 - 14:27:25 EST


On Wed, Aug 28, 2013 at 11:17:46AM -0400, Steven Rostedt wrote:

> Dave, can you add this patch to your kernels you test, and that way,
> the next time you hit this error, I want to see if this warning was
> triggered too.
>
> If we did not unregister the ftrace ops but free the filters, it will
> cause the accounting to get out of whack.
>
> Thanks!
>
> -- Steve
>
> diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
> index 80c36bc..05167bb 100644
> --- a/kernel/trace/trace_event_perf.c
> +++ b/kernel/trace/trace_event_perf.c
> @@ -306,6 +306,7 @@ static int perf_ftrace_function_unregister(struct perf_event *event)
> {
> struct ftrace_ops *ops = &event->ftrace_ops;
> int ret = unregister_ftrace_function(ops);
> + WARN_ON(ret);
> ftrace_free_filter(ops);
> return ret;
> }

I hit the WARN in the subject, and then this new one immediately afterwards.

Dave.

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