Re: Lockup in tracepoint unregister in sched switch ftrace plugin

[Steven Rostedt]

[ Paul, Thomas, wake up ]

On Mon, 20 Oct 2008, Steven Rostedt wrote:
> 
>   which calls unregister_trace_sched_switch define as macro to:
> 
> kernel/tracepoint.c: tracepoint_probe_unregister
>    " "  : remove_tracepoint
> kernel/rcupdate.c: rcu_barrier_sched
>    " "  : _rcu_barrier
> 
> where it gets stuck at that "wait_for_completion".
> 
> I'm not sure if, because this is a scheduler trace point that we are 
> hitting some kind of race that is preventing the wait_for_completion to 
> finish, or what.

Note, I just booted this kernel with CONFIG_NOHZ=n and it booted fine.
This looks like a bug somewhere in tracepoints/RCU/dynamic-ticks

-- Steve

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