Messages in this thread | | | Date | Thu, 5 Feb 2015 15:22:01 -0500 | From | Steven Rostedt <> | Subject | Re: linux-next: Tree for Feb 4 |
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On Thu, 5 Feb 2015 21:07:27 +0100 Sedat Dilek <sedat.dilek@gmail.com> wrote:
> > Is this Paul's version of the patch or mine? If it is just mine, do you > > know if Paul's version triggers this too? > > > > This one which entered Pauls rcu-next tree. > > [1] http://git.kernel.org/cgit/linux/kernel/git/paulmck/linux-rcu.git/commit/?h=rcu/next&id=2b27cf7317d8a99a50bead9faccd54b46b6f0c41
That's mine.
It looks like the condition will be tested before it calls and rcu code. Which is why I was confused that it still gave a splat. Paul posted a patch before this that did the check outside the trace point.
This one:
http://marc.info/?l=linux-kernel&m=142310961217650&w=2
> > >> ( I did not build from scratch but re-invoking make "updated" the > >> files touched by Steven's patch, see attached build-log. ) > >> > >> Unfortunately, the call-trace remains when doing an offlining of cpu1. > >> ( It's good to see it's reproducible. ) > > > > Was the tracepoint enabled? Or was there some other rcu call that > > triggered this. Or would cpu_online(smp_processor_id()) return true at > > this point? > > > > Thanks Steve for jumping into this one! > > Good point. > I looked at my kernel-config (which I already sent :-)). > > Do I need to enable...? > > # CONFIG_RCU_TRACE is not set > > ...or even more? >
What I meant by the tracepoint being enabled, was not that it was configured in (I'm assuming it was), but that you started tracing?
echo 1 > /sys/kernel/debug/tracing/events/enable
or
echo 1 > /sys/kernel/debug/tracing/events/tlb/tlb_flushed/enable
-- Steve
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