Re: Question about ftrace, dynamically allocated trampolines and dynamic fops

From: Steven Rostedt
Date: Fri Jan 30 2015 - 09:12:19 EST


On Fri, 30 Jan 2015 11:08:19 +0100 (CET)
Miroslav Benes <mbenes@xxxxxxx> wrote:

> Anyway I think the problem is the opposite. There should be no
> ftrace_ops_list_func for dynamic trampoline. See below, please...
>


>
> I think so. One thing is the code above. And verification in
> next-20150130 in qemu, CONFIG_PREEMPT=n,...
>
> I livepatched /proc/cmdline and there is no other tracing involved
>
> dsc1:~ # cat /sys/kernel/debug/tracing/enabled_functions
> cmdline_proc_show (1) R I tramp: 0xffffffffa0004000 ->ftrace_ops_list_func+0x0/0x1a0
> dsc1:~
>
> I think that there should be direct call to the callback function (new
> cmdline_proc_show).
>

Ah, OK I see the issue. Yeah, it shouldn't be that way. I'll have to
fix that.

Thanks,

-- Steve
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