Commit be081d9b authored by Stephen Boyd's avatar Stephen Boyd Committed by Catalin Marinas

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 <john.stultz@linaro.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
Reviewed-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: <stable@vger.kernel.org> # 3.17+
Fixes: 45ed695a ("ARM64: add IPI tracepoints")
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 86dca36e
...@@ -693,7 +693,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs) ...@@ -693,7 +693,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
struct pt_regs *old_regs = set_irq_regs(regs); struct pt_regs *old_regs = set_irq_regs(regs);
if ((unsigned)ipinr < NR_IPI) { 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]); __inc_irq_stat(cpu, ipi_irqs[ipinr]);
} }
...@@ -736,7 +736,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs) ...@@ -736,7 +736,7 @@ void handle_IPI(int ipinr, struct pt_regs *regs)
} }
if ((unsigned)ipinr < NR_IPI) if ((unsigned)ipinr < NR_IPI)
trace_ipi_exit(ipi_types[ipinr]); trace_ipi_exit_rcuidle(ipi_types[ipinr]);
set_irq_regs(old_regs); set_irq_regs(old_regs);
} }
......
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