Messages in this thread | | | Date | Fri, 7 Sep 2018 16:02:34 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] printk/tracing: Do not trace printk_nmi_enter() |
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On Fri, Sep 07, 2018 at 09:55:33AM -0400, Steven Rostedt wrote: > On Fri, 7 Sep 2018 15:45:32 +0200 > Peter Zijlstra <peterz@infradead.org> wrote: > > > Yes really, we should not muck with the IRQ state from NMI context. > > Right, and we didn't. Your patch didn't change anything, but allow for
It does, it kills lockdep before we get to mucking with the IRQ state.
> printk_nmi_enter/exit() to be traced by ftrace, but that's wrong to > begin with because it ftrace_nmi_enter() hasn't been called yet.
That's a second bug :-) A better solution might be to inline that function as well. A direct OR instruction is still way faster than a CALL+RET.
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