[PATCH 03/10] power: supply: bq25890: Fix usb-notifier probe and remove races

Hans de Goede
2022-11-27T18:03:49Z

There are 2 races surrounding the usb-notifier:

1. The notifier, and thus usb_work, may run before the bq->charger
power_supply class device is registered. But usb_work may call
power_supply_changed() which relies on the psy device being registered.

2. usb_work may be pending/running at remove() time, so it needs to be
cancelled on remove after unregistering the usb-notifier.

Fix 1. by moving usb-notifier registration to after the power_supply
registration.

Fix 2. by adding a cancel_work_sync() call directly after the usb-notifier
unregistration.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
drivers/power/supply/bq25890_charger.c | 26 +++++++++++---------------
1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/power/supply/bq25890_charger.c b/drivers/power/supply/bq25890_charger.c
index 30d77afab839..032a10a3877b 100644
--- a/drivers/power/supply/bq25890_charger.c
+++ b/drivers/power/supply/bq25890_charger.c
@@ -1387,16 +1387,10 @@ static int bq25890_probe(struct i2c_client *client)
if (ret)
return ret;

- if (!IS_ERR_OR_NULL(bq->usb_phy)) {
- INIT_WORK(&bq->usb_work, bq25890_usb_work);
- bq->usb_nb.notifier_call = bq25890_usb_notifier;
- usb_register_notifier(bq->usb_phy, &bq->usb_nb);
- }
-
ret = bq25890_power_supply_init(bq);
if (ret < 0) {
dev_err(dev, "Failed to register power supply\n");
- goto err_unregister_usb_notifier;
+ return ret;
}

ret = devm_request_threaded_irq(dev, client->irq, NULL,
@@ -1404,23 +1398,25 @@ static int bq25890_probe(struct i2c_client *client)
IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
BQ25890_IRQ_PIN, bq);
if (ret)
- goto err_unregister_usb_notifier;
-
- return 0;
+ return ret;

-err_unregister_usb_notifier:
- if (!IS_ERR_OR_NULL(bq->usb_phy))
- usb_unregister_notifier(bq->usb_phy, &bq->usb_nb);
+ if (!IS_ERR_OR_NULL(bq->usb_phy)) {
+ INIT_WORK(&bq->usb_work, bq25890_usb_work);
+ bq->usb_nb.notifier_call = bq25890_usb_notifier;
+ usb_register_notifier(bq->usb_phy, &bq->usb_nb);
+ }

- return ret;
+ return 0;
}

static void bq25890_remove(struct i2c_client *client)
{
struct bq25890_device *bq = i2c_get_clientdata(client);

- if (!IS_ERR_OR_NULL(bq->usb_phy))
+ if (!IS_ERR_OR_NULL(bq->usb_phy)) {
usb_unregister_notifier(bq->usb_phy, &bq->usb_nb);
+ cancel_work_sync(&bq->usb_work);
+ }

if (!bq->skip_reset) {
/* reset all registers to default values */
--
2.38.1