From 642f33e34b969eedec334738fd5df95d2dc42742 Mon Sep 17 00:00:00 2001 From: Waqar Hameed Date: Sat, 20 Dec 2025 23:36:00 +0100 Subject: [PATCH] power: supply: cpcap-battery: 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: 874b2adbed12 ("power: supply: cpcap-battery: Add a battery driver") Signed-off-by: Waqar Hameed Link: https://patch.msgid.link/81db58d610c9a51a68184f856cd431a934cccee2.1766268280.git.waqar.hameed@axis.com Signed-off-by: Sebastian Reichel --- drivers/power/supply/cpcap-battery.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/power/supply/cpcap-battery.c b/drivers/power/supply/cpcap-battery.c index 8106d1edcbc26..507fdc1c866d5 100644 --- a/drivers/power/supply/cpcap-battery.c +++ b/drivers/power/supply/cpcap-battery.c @@ -1122,10 +1122,6 @@ static int cpcap_battery_probe(struct platform_device *pdev) platform_set_drvdata(pdev, ddata); - error = cpcap_battery_init_interrupts(pdev, ddata); - if (error) - return error; - error = cpcap_battery_init_iio(ddata); if (error) return error; @@ -1142,6 +1138,10 @@ static int cpcap_battery_probe(struct platform_device *pdev) return error; } + error = cpcap_battery_init_interrupts(pdev, ddata); + if (error) + return error; + atomic_set(&ddata->active, 1); error = cpcap_battery_calibrate(ddata); -- 2.47.3