From e2febe375e5ea5afed92f4cd9711bde8f24ee6d2 Mon Sep 17 00:00:00 2001 From: Waqar Hameed Date: Sat, 20 Dec 2025 23:36:02 +0100 Subject: [PATCH] power: supply: rt9455: 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: e86d69dd786e ("power_supply: Add support for Richtek RT9455 battery charger") Signed-off-by: Waqar Hameed Link: https://patch.msgid.link/1567d831e04c3e2fcb9e18dd36b7bcba4634581a.1766268280.git.waqar.hameed@axis.com Signed-off-by: Sebastian Reichel --- drivers/power/supply/rt9455_charger.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/drivers/power/supply/rt9455_charger.c b/drivers/power/supply/rt9455_charger.c index 1ffe7f02932f6..5130d2395e88f 100644 --- a/drivers/power/supply/rt9455_charger.c +++ b/drivers/power/supply/rt9455_charger.c @@ -1663,6 +1663,15 @@ static int rt9455_probe(struct i2c_client *client) rt9455_charger_config.supplied_to = rt9455_charger_supplied_to; rt9455_charger_config.num_supplicants = ARRAY_SIZE(rt9455_charger_supplied_to); + + info->charger = devm_power_supply_register(dev, &rt9455_charger_desc, + &rt9455_charger_config); + if (IS_ERR(info->charger)) { + dev_err(dev, "Failed to register charger\n"); + ret = PTR_ERR(info->charger); + goto put_usb_notifier; + } + ret = devm_request_threaded_irq(dev, client->irq, NULL, rt9455_irq_handler_thread, IRQF_TRIGGER_LOW | IRQF_ONESHOT, @@ -1678,14 +1687,6 @@ static int rt9455_probe(struct i2c_client *client) goto put_usb_notifier; } - info->charger = devm_power_supply_register(dev, &rt9455_charger_desc, - &rt9455_charger_config); - if (IS_ERR(info->charger)) { - dev_err(dev, "Failed to register charger\n"); - ret = PTR_ERR(info->charger); - goto put_usb_notifier; - } - return 0; put_usb_notifier: -- 2.47.3