2020-11-27 14:17:32

by Hanks Chen

[permalink] [raw]
Subject: [PATCH v1 2/3] arm: disable irq on cpu shutdown flow

Disable irq on cpu shutdown flow to ensure interrupts
did not bother this cpu after status as offline.

To avoid suspicious RCU usage
[0:swapper/0]RCU used illegally from offline CPU! ...
[0:swapper/0]lockdep: [name:lockdep&]cpu_id = 0, cpu_is_offline = 1

Signed-off-by: Hanks Chen <[email protected]>
---
arch/arm/kernel/smp.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 48099c6e1e4a..6b8f72490320 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -262,6 +262,12 @@ int __cpu_disable(void)
remove_cpu_topology(cpu);
#endif

+ /*
+ * we disable irq here to ensure interrupts
+ * did not bother this cpu after status as offline.
+ */
+ local_irq_disable();
+
/*
* Take this CPU offline. Once we clear this, we can't return,
* and we must not schedule until we're ready to give up the cpu.
@@ -600,11 +606,11 @@ static void ipi_cpu_stop(unsigned int cpu)
raw_spin_unlock(&stop_lock);
}

- set_cpu_online(cpu, false);
-
local_fiq_disable();
local_irq_disable();

+ set_cpu_online(cpu, false);
+
while (1) {
cpu_relax();
wfe();
--
2.18.0