[tip: irq/urgent] genirq: Unlock irq descriptor after errors

From: tip-bot2 for Guenter Roeck
Date: Thu Aug 13 2020 - 03:42:19 EST


The following commit has been merged into the irq/urgent branch of tip:

Commit-ID: f107cee94ba4d2c7357fde59a1d84346c73d4958
Gitweb: https://git.kernel.org/tip/f107cee94ba4d2c7357fde59a1d84346c73d4958
Author: Guenter Roeck <linux@xxxxxxxxxxxx>
AuthorDate: Tue, 11 Aug 2020 11:00:12 -07:00
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitterDate: Thu, 13 Aug 2020 09:35:59 +02:00

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 fix it.

Fixes: 1d0326f352bb ("genirq: Check irq_data_get_irq_chip() return value before use")
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20200811180012.80269-1-linux@xxxxxxxxxxxx

---
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 d55ba62..52ac539 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;
}