From: Waqar Hameed Date: Sat, 20 Dec 2025 22:35:59 +0000 (+0100) Subject: power: supply: bq256xx: Fix use-after-free in power_supply_changed() X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8005843369723d9c8975b7c4202d1b85d6125302;p=thirdparty%2Flinux.git power: supply: bq256xx: Fix use-after-free in power_supply_changed() Using the `devm_` variant for requesting IRQ _before_ the `devm_` variant for allocating/registering the `power_supply` handle, means that the `power_supply` handle will be deallocated/unregistered _before_ the interrupt handler (since `devm_` naturally deallocates in reverse allocation order). This means that during removal, there is a race condition where an interrupt can fire just _after_ the `power_supply` handle has been freed, *but* just _before_ the corresponding unregistration of the IRQ handler has run. This will lead to the IRQ handler calling `power_supply_changed()` with a freed `power_supply` handle. Which usually crashes the system or otherwise silently corrupts the memory... Note that there is a similar situation which can also happen during `probe()`; the possibility of an interrupt firing _before_ registering the `power_supply` handle. This would then lead to the nasty situation of using the `power_supply` handle *uninitialized* in `power_supply_changed()`. Fix this racy use-after-free by making sure the IRQ is requested _after_ the registration of the `power_supply` handle. Fixes: 32e4978bb920 ("power: supply: bq256xx: Introduce the BQ256XX charger driver") Signed-off-by: Waqar Hameed Link: https://patch.msgid.link/39da6da8cc060fa0382ca859f65071e791cb6119.1766268280.git.waqar.hameed@axis.com Signed-off-by: Sebastian Reichel --- diff --git a/drivers/power/supply/bq256xx_charger.c b/drivers/power/supply/bq256xx_charger.c index 3eb1733940054..563f512709b38 100644 --- a/drivers/power/supply/bq256xx_charger.c +++ b/drivers/power/supply/bq256xx_charger.c @@ -1740,6 +1740,12 @@ static int bq256xx_probe(struct i2c_client *client) usb_register_notifier(bq->usb3_phy, &bq->usb_nb); } + ret = bq256xx_power_supply_init(bq, &psy_cfg, dev); + if (ret) { + dev_err(dev, "Failed to register power supply\n"); + return ret; + } + if (client->irq) { ret = devm_request_threaded_irq(dev, client->irq, NULL, bq256xx_irq_handler_thread, @@ -1752,12 +1758,6 @@ static int bq256xx_probe(struct i2c_client *client) } } - ret = bq256xx_power_supply_init(bq, &psy_cfg, dev); - if (ret) { - dev_err(dev, "Failed to register power supply\n"); - return ret; - } - ret = bq256xx_hw_init(bq); if (ret) { dev_err(dev, "Cannot initialize the chip.\n");