On Mon, 2019-06-17 at 19:09 -0400, Steven Rostedt wrote:
> On Mon, 17 Jun 2019 08:26:29 -0700
> Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx> wrote:
>
> > On Mon, Jun 17, 2019 at 5:59 AM Arnd Bergmann <arnd@xxxxxxxx> wrote:
> > >
> > > When CONFIG_MODULES is disabled, this function is never called:
> > >
> > > kernel/trace/bpf_trace.c:581:13: error: 'do_bpf_send_signal' defined but not used [-Werror=unused-function]
> >
> > hmm. it should work just fine without modules.
> > the bug is somewhere else.
>
> From what I see, the only use of do_bpf_send_signal is within a
> #ifdef CONFIG_MODULES, which means that you will get a warning about a
> static unused when CONFIG_MODULES is not defined.
>
> In kernel/trace/bpf_trace.c we have:
>
> static void do_bpf_send_signal(struct irq_work *entry)
>
> [..]
>
> #ifdef CONFIG_MODULES
>
> [..]
>
> for_each_possible_cpu(cpu) {
> work = per_cpu_ptr(&send_signal_work, cpu);
> init_irq_work(&work->irq_work, do_bpf_send_signal); <-- on use of do_bpf_send_signal
> }
> [..]
> #endif /* CONFIG_MODULES */
>
> The bug (really just a warning) reported is exactly here.
I don't think bpf_send_signal is tied to modules at all;
send_signal_irq_work_init and the corresponding initcall should be
moved outside that #ifdef.
>
> -- Steve
