From 2dd7172e36d015013859e5afd3abaeffa92e9397 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 commit be081d9bf3e163a9ed1ca2f0f14f08424c7f9016 upstream. 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 Fixes: 45ed695ac10a ("ARM64: add IPI tracepoints") Signed-off-by: Stephen Boyd Signed-off-by: Catalin Marinas Signed-off-by: Greg Kroah-Hartman --- 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 2cb008177252..d3a202b85ba6 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c @@ -569,7 +569,7 @@ 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]); } @@ -612,7 +612,7 @@ 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); } -- 2.50.1