[PATCH] ARM64: smp: Silence suspicious RCU usage with ipi tracepoints

Peter Zijlstra peterz at infradead.org
Wed Jun 24 14:29:30 PDT 2015


On Wed, Jun 24, 2015 at 01:14:18PM -0700, Stephen Boyd wrote:
> John Stultz reported an RCU splat on ARM with ipi trace events
> enabled. It looks like the same problem exists on ARM64.
> 
> At this point in the IPI handling path we haven't called
> irq_enter() yet, so RCU doesn't know that we're about to exit
> idle and properly warns that we're using RCU from an idle CPU.
> Use trace_ipi_entry_rcuidle() instead of trace_ipi_entry() so
> that RCU is informed about our exit from idle.

I have a problem with $subject. It says 'silence', whereas afaict this
fixes an actual bug, so it should be 'fixes'.



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