linux-kernel - [PATCH] genirq: Unlock irq descriptor after errors

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Message-Id: <20200811180012.80269-1-linux@roeck-us.net>
Date:   Tue, 11 Aug 2020 11:00:12 -0700
From:   Guenter Roeck <linux@...ck-us.net>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     linux-kernel@...r.kernel.org, Guenter Roeck <linux@...ck-us.net>,
        Marek Vasut <marex@...x.de>
Subject: [PATCH] genirq: Unlock irq descriptor after errors

In irq_set_irqchip_state(), the irq descriptor is not unlocked
after an error is encountered. While that should never happen
in practice, a buggy driver may trigger it. This would result
in a lockup, so let's fix it.

Fixes: 1d0326f352bb ("genirq: Check irq_data_get_irq_chip() return value before use")
Cc: Marek Vasut <marex@...x.de>
Signed-off-by: Guenter Roeck <linux@...ck-us.net>
---
 kernel/irq/manage.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index d55ba625d426..52ac5391dcc6 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -2731,8 +2731,10 @@ int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
 
 	do {
 		chip = irq_data_get_irq_chip(data);
-		if (WARN_ON_ONCE(!chip))
-			return -ENODEV;
+		if (WARN_ON_ONCE(!chip)) {
+			err = -ENODEV;
+			goto out_unlock;
+		}
 		if (chip->irq_set_irqchip_state)
 			break;
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
@@ -2745,6 +2747,7 @@ int irq_set_irqchip_state(unsigned int irq, enum irqchip_irq_state which,
 	if (data)
 		err = chip->irq_set_irqchip_state(data, which, val);
 
+out_unlock:
 	irq_put_desc_busunlock(desc, flags);
 	return err;
 }
-- 
2.17.1