[PATCH 24/28] mfd: tps65217: Manage IRQ domain teardown via devres

[Lee Jones <lee@kernel.org>]

tps65217_irq_init() creates tps->irq_domain with an unmanaged call and
requests the parent interrupt via devm_request_threaded_irq(), while
tps65217_remove() manually disposes mappings and removes
tps->irq_domain.  Because tps65217_remove() executes before devres
teardown, the IRQ domain is destroyed while tps65217_irq_thread() and
child MFD devices are still active, allowing a concurrent interrupt to
dereference a freed or NULL domain.  Furthermore, if probe fails after
irq_domain_create_linear() or if tps65217_irq_init() fails, the IRQ
domain is leaked, and if the device is probed without an interrupt
(client->irq == 0), tps65217_remove() unconditionally passes a NULL
tps->irq_domain to irq_domain_remove().

Register a devres action to tear down the IRQ domain in
tps65217_irq_init() prior to devm_request_threaded_irq(), propagate
errors from tps65217_irq_init() in tps65217_probe(), and drop
tps65217_remove().

Fixes: 40a50f8b307d ("mfd: tps65217: Fix page fault on unloading modules")
Closes: https://sashiko.dev/#/bug/linux-7e358c08-6d75-48be-87d2-35dc037ea953
Cc: stable@vger.kernel.org
Signed-off-by: Lee Jones <lee@kernel.org>
---
 drivers/mfd/tps65217.c | 40 ++++++++++++++++++++++------------------
 1 file changed, 22 insertions(+), 18 deletions(-)

diff --git a/drivers/mfd/tps65217.c b/drivers/mfd/tps65217.c
index c240fac0ede7..a1e9b9e22d82 100644
--- a/drivers/mfd/tps65217.c
+++ b/drivers/mfd/tps65217.c
@@ -146,6 +146,21 @@ static const struct irq_domain_ops tps65217_irq_domain_ops = {
 	.map = tps65217_irq_map,
 };
 
+static void tps65217_irq_exit(void *data)
+{
+	struct tps65217 *tps = data;
+	unsigned int virq;
+
+	for (int i = 0; i < TPS65217_NUM_IRQ; i++) {
+		virq = irq_find_mapping(tps->irq_domain, i);
+		if (virq)
+			irq_dispose_mapping(virq);
+	}
+
+	irq_domain_remove(tps->irq_domain);
+	tps->irq_domain = NULL;
+}
+
 static int tps65217_irq_init(struct tps65217 *tps, int irq)
 {
 	int ret;
@@ -165,6 +180,10 @@ static int tps65217_irq_init(struct tps65217 *tps, int irq)
 		return -ENOMEM;
 	}
 
+	ret = devm_add_action_or_reset(tps->dev, tps65217_irq_exit, tps);
+	if (ret)
+		return ret;
+
 	ret = devm_request_threaded_irq(tps->dev, irq, NULL,
 					tps65217_irq_thread, IRQF_ONESHOT,
 					"tps65217-irq", tps);
@@ -333,7 +352,9 @@ static int tps65217_probe(struct i2c_client *client)
 	}
 
 	if (client->irq) {
-		tps65217_irq_init(tps, client->irq);
+		ret = tps65217_irq_init(tps, client->irq);
+		if (ret)
+			return ret;
 	} else {
 		int i;
 
@@ -373,22 +394,6 @@ static int tps65217_probe(struct i2c_client *client)
 	return 0;
 }
 
-static void tps65217_remove(struct i2c_client *client)
-{
-	struct tps65217 *tps = i2c_get_clientdata(client);
-	unsigned int virq;
-	int i;
-
-	for (i = 0; i < TPS65217_NUM_IRQ; i++) {
-		virq = irq_find_mapping(tps->irq_domain, i);
-		if (virq)
-			irq_dispose_mapping(virq);
-	}
-
-	irq_domain_remove(tps->irq_domain);
-	tps->irq_domain = NULL;
-}
-
 static const struct i2c_device_id tps65217_id_table[] = {
 	{"tps65217", TPS65217},
 	{ /* sentinel */ }
@@ -402,7 +407,6 @@ static struct i2c_driver tps65217_driver = {
 	},
 	.id_table	= tps65217_id_table,
 	.probe		= tps65217_probe,
-	.remove		= tps65217_remove,
 };
 
 static int __init tps65217_init(void)
-- 
2.56.0.218.g1ec904b173-goog