Re: [PATCH v4 05/27] x86: Replace ist_enter() with nmi_enter()

Peter Zijlstra
2020-02-24T21:32:27Z

On Mon, Feb 24, 2020 at 11:47:54AM -0500, Steven Rostedt wrote:
> On Mon, 24 Feb 2020 17:34:09 +0100
> Peter Zijlstra <peterz@infradead.org> wrote:
>
> > Looking at nmi_enter(), that leaves trace_hardirq_enter(), since we know
> > we marked rcu_nmi_enter() as NOKPROBES, per the patches elsewhere in
> > this series.
>
> Maybe this was addressed already in the series, but I'm just looking at
> Linus's master branch we have:
>
> #define nmi_enter() \
> do { \
> arch_nmi_enter(); \
> printk_nmi_enter(); \
> lockdep_off(); \
> ftrace_nmi_enter(); \
> BUG_ON(in_nmi()); \
> preempt_count_add(NMI_OFFSET + HARDIRQ_OFFSET); \
> rcu_nmi_enter(); \
> trace_hardirq_enter(); \
> } while (0)
>
>
> Just want to confirm that printk_nmi_enter(), lockdep_off(),
> and ftrace_nmi_enter() are all marked fully with NOKPROBE.

*sigh*, right you are, I only looked at notrace, not nokprobe.

In particular the ftrace one is a bit off a mess, let me sort through
that.