From 3291c51d4684d048dd2eb91b5b65fcfdaf72141f Mon Sep 17 00:00:00 2001 From: Waqar Hameed Date: Sat, 20 Dec 2025 23:35:59 +0100 Subject: [PATCH] power: supply: act8945a: 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: a09209acd6a8 ("power: supply: act8945a_charger: Add status change update support") Signed-off-by: Waqar Hameed Link: https://patch.msgid.link/bcf3a23b5187df0bba54a8c8fe09f8b8a0031dee.1766268280.git.waqar.hameed@axis.com Signed-off-by: Sebastian Reichel --- drivers/power/supply/act8945a_charger.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/power/supply/act8945a_charger.c b/drivers/power/supply/act8945a_charger.c index 3901a02f326a5..9dec4486b1439 100644 --- a/drivers/power/supply/act8945a_charger.c +++ b/drivers/power/supply/act8945a_charger.c @@ -597,14 +597,6 @@ static int act8945a_charger_probe(struct platform_device *pdev) return irq ?: -ENXIO; } - ret = devm_request_irq(&pdev->dev, irq, act8945a_status_changed, - IRQF_TRIGGER_FALLING, "act8945a_interrupt", - charger); - if (ret) { - dev_err(&pdev->dev, "failed to request nIRQ pin IRQ\n"); - return ret; - } - charger->desc.name = "act8945a-charger"; charger->desc.get_property = act8945a_charger_get_property; charger->desc.properties = act8945a_charger_props; @@ -625,6 +617,14 @@ static int act8945a_charger_probe(struct platform_device *pdev) return PTR_ERR(charger->psy); } + ret = devm_request_irq(&pdev->dev, irq, act8945a_status_changed, + IRQF_TRIGGER_FALLING, "act8945a_interrupt", + charger); + if (ret) { + dev_err(&pdev->dev, "failed to request nIRQ pin IRQ\n"); + return ret; + } + platform_set_drvdata(pdev, charger); INIT_WORK(&charger->work, act8945a_work); -- 2.47.3