From be081d9bf3e163a9ed1ca2f0f14f08424c7f9016 Mon Sep 17 00:00:00 2001 From: Stephen Boyd Date: Wed, 24 Jun 2015 13:14:18 -0700 Subject: [PATCH] ARM64: smp: Fix suspicious RCU usage with ipi tracepoints 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. Cc: John Stultz Cc: Nicolas Pitre Acked-by: Steven Rostedt Reviewed-by: Paul E. McKenney Cc: # 3.17+ Fixes: 45ed695ac10a ("ARM64: add IPI tracepoints") Signed-off-by: Stephen Boyd Signed-off-by: Catalin Marinas --- arch/arm64/kernel/smp.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index 4b2121b..a1883bf 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -693,7 +693,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs) struct pt_regs *old_regs = set_irq_regs(regs); if ((unsigned)ipinr < NR_IPI) { - trace_ipi_entry(ipi_types[ipinr]); + trace_ipi_entry_rcuidle(ipi_types[ipinr]); __inc_irq_stat(cpu, ipi_irqs[ipinr]); } @@ -736,7 +736,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs) } if ((unsigned)ipinr < NR_IPI) - trace_ipi_exit(ipi_types[ipinr]); + trace_ipi_exit_rcuidle(ipi_types[ipinr]); set_irq_regs(old_regs); } -- 2.7.4