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From:   Zenghui Yu <yuzenghui@huawei.com>
To:     <marc.zyngier@arm.com>, <julien.thierry@arm.com>,
        <rostedt@goodmis.org>
CC:     <mingo@redhat.com>, <catalin.marinas@arm.com>,
        <will.deacon@arm.com>, <mark.rutland@arm.com>,
        <linux@armlinux.org.uk>, <james.morse@arm.com>,
        <suzuki.poulose@arm.com>, <wanghaibin.wang@huawei.com>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, Zenghui Yu <yuzenghui@huawei.com>
Subject: [RFC PATCH] irqchip/gic-v3: Make gic_handle_irq() notrace
Date:   Fri, 29 Mar 2019 13:23:28 +0000
Message-ID: <1553865808-30604-1-git-send-email-yuzenghui@huawei.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

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@arm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Zenghui Yu <yuzenghui@huawei.com>
---
 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