From b2ce982e2e0c888dc55c888ad0e20ea04daf2e6b Mon Sep 17 00:00:00 2001 From: Waqar Hameed Date: Sat, 20 Dec 2025 23:36:00 +0100 Subject: [PATCH] power: supply: goldfish: 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: 84d7b7687489 ("power: Add battery driver for goldfish emulator") Signed-off-by: Waqar Hameed Link: https://patch.msgid.link/500a606bb6fb6f2bb8d797e19a00cea9dd7b03c1.1766268280.git.waqar.hameed@axis.com Signed-off-by: Sebastian Reichel --- drivers/power/supply/goldfish_battery.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/power/supply/goldfish_battery.c b/drivers/power/supply/goldfish_battery.c index 479195e35d734..5aa24e4dc4455 100644 --- a/drivers/power/supply/goldfish_battery.c +++ b/drivers/power/supply/goldfish_battery.c @@ -224,12 +224,6 @@ static int goldfish_battery_probe(struct platform_device *pdev) if (data->irq < 0) return -ENODEV; - ret = devm_request_irq(&pdev->dev, data->irq, - goldfish_battery_interrupt, - IRQF_SHARED, pdev->name, data); - if (ret) - return ret; - psy_cfg.drv_data = data; data->ac = devm_power_supply_register(&pdev->dev, @@ -244,6 +238,12 @@ static int goldfish_battery_probe(struct platform_device *pdev) if (IS_ERR(data->battery)) return PTR_ERR(data->battery); + ret = devm_request_irq(&pdev->dev, data->irq, + goldfish_battery_interrupt, + IRQF_SHARED, pdev->name, data); + if (ret) + return ret; + GOLDFISH_BATTERY_WRITE(data, BATTERY_INT_ENABLE, BATTERY_INT_MASK); return 0; } -- 2.47.3