[RFC PATCH] irqchip/gic-v3: Make gic_handle_irq() notrace

From: Zenghui Yu
Date: Fri Mar 29 2019 - 09:24:44 EST


Enable pseudo NMI together with function_graph tracer, will lead
the system to a hang. This is easy to reproduce,

1) Set "irqchip.gicv3_pseudo_nmi=1" on the kernel command line
2) echo function_graph > /sys/kernel/debug/tracing/current_tracer

This patch (RFC) set gic_handle_irq() as notrace and it seems works
fine now. But I have no idea about what the issue is exactly, and
you can regard this patch as a report then :)

Can someone give a look at it and provide some explanations ?

Thanks!

Cc: Julien Thierry <julien.thierry@xxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Signed-off-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>
---
drivers/irqchip/irq-gic-v3.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/irqchip/irq-gic-v3.c b/drivers/irqchip/irq-gic-v3.c
index 15e55d3..8d0c25f 100644
--- a/drivers/irqchip/irq-gic-v3.c
+++ b/drivers/irqchip/irq-gic-v3.c
@@ -487,7 +487,7 @@ static inline void gic_handle_nmi(u32 irqnr, struct pt_regs *regs)
gic_deactivate_unhandled(irqnr);
}

-static asmlinkage void __exception_irq_entry gic_handle_irq(struct pt_regs *regs)
+static asmlinkage notrace void __exception_irq_entry gic_handle_irq(struct pt_regs *regs)
{
u32 irqnr;

--
1.8.3.1