Messages in this thread | | | From | Andy Lutomirski <> | Subject | Re: [patch 4/8] x86/entry: Move irq tracing on syscall entry to C-code | Date | Sun, 1 Mar 2020 06:37:04 -0800 |
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> On Mar 1, 2020, at 2:16 AM, Thomas Gleixner <tglx@linutronix.de> wrote: > > Steven Rostedt <rostedt@goodmis.org> writes: > >> On Sat, 29 Feb 2020 11:25:24 -0800 >> Andy Lutomirski <luto@amacapital.net> wrote: >> >>>> While the tracer itself seems to handle this correctly, what about >>>> things like BPF programs which can be attached to tracepoints and >>>> function trace entries? >>> >>> I think that everything using the tracing code, including BPF, should >>> either do its own rcuidle stuff or explicitly not execute if we’re >>> not in CONTEXT_KERNEL. That is, we probably need to patch BPF. >> >> That's basically the route we are taking. > > Ok, but for the time being anything before/after CONTEXT_KERNEL is unsafe > except trace_hardirq_off/on() as those trace functions do not allow to > attach anything AFAICT.
Can you point to whatever makes those particular functions special? I failed to follow the macro maze.
> > Thanks, > > tglx
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