[PATCH v3] mfd: da903x: cancel IRQ work during teardown

[Hongyan Xu <getshell@seu.edu.cn>]

The IRQ handler disables the IRQ and schedules irq_work. Releasing the
IRQ does not drain that work, which can continue to use the devm-allocated
chip and notifier state.

Manage both IRQ-work cancellation and subdevice removal with devres.
Register the subdevice-removal action before requesting the IRQ, then add
the IRQ-work action after the request. This avoids leaving a live IRQ
without work cancellation if action registration fails. Devres cleanup
then disables the IRQ and drains the work before releasing the IRQ and
removing child devices. Register both actions before creating the children
so partial probe failures use the same ordering.

This issue was found by the author's in-house static analysis tool.
The patch was reviewed by the author against the latest mainline tree.

Fixes: 26b8f5e1e2d1 ("mfd: add base support for Dialog DA9030/DA9034 PMICs")
Cc: stable@vger.kernel.org
Suggested-by: Lee Jones <lee@kernel.org>
Assisted-by: Codex:GPT-5
Signed-off-by: Hongyan Xu <getshell@seu.edu.cn>
---
Changes in v3:
- Manage subdevice removal with devres and drop the remove callback.
- Register its action before IRQ acquisition, then register IRQ-work
  cancellation after it, covering action and partial-probe failures.

 drivers/mfd/da903x.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

diff --git a/drivers/mfd/da903x.c b/drivers/mfd/da903x.c
index e86b39de3303..e4ad48e1f139 100644
--- a/drivers/mfd/da903x.c
+++ b/drivers/mfd/da903x.c
@@ -421,6 +421,14 @@ static irqreturn_t da903x_irq_handler(int irq, void *data)
 	return IRQ_HANDLED;
 }
 
+static void da903x_cancel_irq_work(void *data)
+{
+	struct da903x_chip *chip = data;
+
+	disable_irq(chip->client->irq);
+	cancel_work_sync(&chip->irq_work);
+}
+
 static const struct da903x_chip_ops da903x_ops[] = {
 	[0] = {
 		.init_chip	= da9030_init_chip,
@@ -456,6 +464,13 @@ static int da903x_remove_subdevs(struct da903x_chip *chip)
 	return device_for_each_child(chip->dev, NULL, __remove_subdev);
 }
 
+static void da903x_remove_subdevs_action(void *data)
+{
+	struct da903x_chip *chip = data;
+
+	da903x_remove_subdevs(chip);
+}
+
 static int da903x_add_subdevs(struct da903x_chip *chip,
 					struct da903x_platform_data *pdata)
 {
@@ -484,7 +499,6 @@ static int da903x_add_subdevs(struct da903x_chip *chip,
 	return 0;
 
 failed:
-	da903x_remove_subdevs(chip);
 	return ret;
 }
 
@@ -520,6 +534,11 @@ static int da903x_probe(struct i2c_client *client)
 	chip->ops->mask_events(chip, chip->events_mask);
 	chip->ops->read_events(chip, &tmp);
 
+	ret = devm_add_action_or_reset(&client->dev,
+				       da903x_remove_subdevs_action, chip);
+	if (ret)
+		return ret;
+
 	ret = devm_request_irq(&client->dev, client->irq, da903x_irq_handler,
 			IRQF_TRIGGER_FALLING,
 			"da903x", chip);
@@ -529,14 +548,12 @@ static int da903x_probe(struct i2c_client *client)
 		return ret;
 	}
 
-	return da903x_add_subdevs(chip, pdata);
-}
-
-static void da903x_remove(struct i2c_client *client)
-{
-	struct da903x_chip *chip = i2c_get_clientdata(client);
+	ret = devm_add_action_or_reset(&client->dev, da903x_cancel_irq_work,
+				       chip);
+	if (ret)
+		return ret;
 
-	da903x_remove_subdevs(chip);
+	return da903x_add_subdevs(chip, pdata);
 }
 
 static struct i2c_driver da903x_driver = {
@@ -544,7 +561,6 @@ static struct i2c_driver da903x_driver = {
 		.name	= "da903x",
 	},
 	.probe		= da903x_probe,
-	.remove		= da903x_remove,
 	.id_table	= da903x_id_table,
 };
 
-- 
2.50.1.windows.1