[PATCH 6/9] pm/irq: make for_each_irq_desc() safe of irq_desc release

Pingfan Liu
2022-04-20T14:06:14Z

The invloved context is no a RCU read section. Furthermore there may be
more than one task at this point. Hence it demands a measure to prevent
irq_desc from freeing. Use irq_lock_sparse to serve the protection
purpose.

Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
To: linux-kernel@vger.kernel.org
---
kernel/irq/pm.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/kernel/irq/pm.c b/kernel/irq/pm.c
index ca71123a6130..4b67a4c7de3c 100644
--- a/kernel/irq/pm.c
+++ b/kernel/irq/pm.c
@@ -133,6 +133,7 @@ void suspend_device_irqs(void)
struct irq_desc *desc;
int irq;

+ irq_lock_sparse();
for_each_irq_desc(irq, desc) {
unsigned long flags;
bool sync;
@@ -146,6 +147,7 @@ void suspend_device_irqs(void)
if (sync)
synchronize_irq(irq);
}
+ irq_unlock_sparse();
}
EXPORT_SYMBOL_GPL(suspend_device_irqs);

@@ -186,6 +188,7 @@ static void resume_irqs(bool want_early)
struct irq_desc *desc;
int irq;

+ /* The early resume stage is free of irq_desc release */
for_each_irq_desc(irq, desc) {
unsigned long flags;
bool is_early = desc->action &&
--
2.31.1