linux-kernel - [PATCH 2/2] genirq: proc: fix a procfs entry leak

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Date:   Mon, 14 Aug 2023 11:36:21 +0200
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Marc Zyngier <marc.zyngier@....com>
Cc:     linux-kernel@...r.kernel.org,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
Subject: [PATCH 2/2] genirq: proc: fix a procfs entry leak

From: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>

When removing the proc entry for a desc that still has active users, we
will leak the irqaction entries. Let's remove them in
unregister_irq_proc().

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@...aro.org>
---
 kernel/irq/proc.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/kernel/irq/proc.c b/kernel/irq/proc.c
index 83ed403991c6..b284604a091a 100644
--- a/kernel/irq/proc.c
+++ b/kernel/irq/proc.c
@@ -390,6 +390,15 @@ void register_irq_proc(unsigned int irq, struct irq_desc *desc)
 	mutex_unlock(&register_lock);
 }
 
+static void unregister_action_proc(struct irqaction *action)
+{
+	if (!action)
+		return;
+
+	unregister_action_proc(action->secondary);
+	unregister_handler_proc(action);
+}
+
 void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
 {
 	char name [MAX_NAMELEN];
@@ -408,6 +417,12 @@ void unregister_irq_proc(unsigned int irq, struct irq_desc *desc)
 #endif
 	remove_proc_entry("spurious", desc->dir);
 
+	/*
+	 * If at this point, this irq desc is still requested, we need to
+	 * remove the proc handler entries or we'll leak them.
+	 */
+	unregister_action_proc(desc->action);
+
 	sprintf(name, "%u", irq);
 	remove_proc_entry(name, root_irq_dir);
 }
-- 
2.39.2