[PATCH 2/2] irqchip/sifive-plic: Fix the interrupt was enabled accidentally issue.

From: Greentime Hu
Date: Mon Oct 12 2020 - 09:58:21 EST


In commit 2ca0b460bbcb ("genirq/affinity: Make affinity setting if activated opt-in"),
it added irqd_affinity_on_activate() checking in the function
irq_set_affinity_deactivated() so it will return false here.
In that case, it will call irq_try_set_affinity() -> plic_irq_toggle()
which will enable the interrupt to cause the CPU hang.

if (irq_set_affinity_deactivated())
return 0;
...
irq_try_set_affinity(data, mask, force);

[ 919.015783] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 919.020922] rcu: 0-...0: (0 ticks this GP)
idle=7d2/1/0x4000000000000002 softirq=1424/1424 fqs=105807
[ 919.030295] (detected by 1, t=225825 jiffies, g=1561, q=3496)
[ 919.036109] Task dump for CPU 0:
[ 919.039321] kworker/0:1 R running task 0 30 2 0x00000008
[ 919.046359] Workqueue: events set_brightness_delayed
[ 919.051302] Call Trace:
[ 919.053738] [<ffffffe000930d92>] __schedule+0x194/0x4de
[ 982.035783] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[ 982.040923] rcu: 0-...0: (0 ticks this GP)
idle=7d2/1/0x4000000000000002 softirq=1424/1424 fqs=113325
[ 982.050294] (detected by 1, t=241580 jiffies, g=1561, q=3509)
[ 982.056108] Task dump for CPU 0:
[ 982.059321] kworker/0:1 R running task 0 30 2 0x00000008
[ 982.066359] Workqueue: events set_brightness_delayed
[ 982.071302] Call Trace:
[ 982.073739] [<ffffffe000930d92>] __schedule+0x194/0x4de
[..]

After applying this patch, the CPU hang issue can be fixed.

Signed-off-by: Greentime Hu <greentime.hu@xxxxxxxxxx>
---
drivers/irqchip/irq-sifive-plic.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index 4cc8a2657a6d..8a673d9cff69 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -183,10 +183,14 @@ static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
struct plic_priv *priv = d->host_data;
+ struct irq_data *irqd;

irq_domain_set_info(d, irq, hwirq, &plic_chip, d->host_data,
handle_fasteoi_irq, NULL, NULL);
irq_set_noprobe(irq);
+ irqd = irq_get_irq_data(irq);
+ irqd_set_single_target(irqd);
+ irqd_set_affinity_on_activate(irqd);
irq_set_affinity(irq, &priv->lmask);
return 0;
}
--
2.28.0