Messages in this thread | | | Date | Fri, 15 Oct 2021 20:24:59 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH] tracing: Have all levels of checks prevent recursion |
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On Fri, Oct 15, 2021 at 02:20:33PM -0400, Steven Rostedt wrote: > On Fri, 15 Oct 2021 20:04:29 +0200 > Peter Zijlstra <peterz@infradead.org> wrote: > > > On Fri, Oct 15, 2021 at 01:58:06PM -0400, Steven Rostedt wrote: > > > Something like this: > > > > I think having one copy of that in a header is better than having 3 > > copies. But yes, something along them lines. > > I was just about to ask you about this patch ;-)
Much better :-)
> diff --git a/kernel/events/internal.h b/kernel/events/internal.h > index 228801e20788..c91711f20cf8 100644 > --- a/kernel/events/internal.h > +++ b/kernel/events/internal.h > @@ -206,11 +206,7 @@ DEFINE_OUTPUT_COPY(__output_copy_user, arch_perf_out_copy_user) > static inline int get_recursion_context(int *recursion) > { > unsigned int pc = preempt_count();
Although I think we can do without that ^ line as well :-)
> - unsigned char rctx = 0; > - > - rctx += !!(pc & (NMI_MASK)); > - rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK)); > - rctx += !!(pc & (NMI_MASK | HARDIRQ_MASK | SOFTIRQ_OFFSET)); > + unsigned char rctx = interrupt_context_level(); > > if (recursion[rctx]) > return -1;
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