[PATCH 5.15 097/164] power: supply: act8945a: Fix use-after-free in power_supply_changed()

Sasha Levin
2026-02-28T18:16:27Z

From: Waqar Hameed <waqar.hameed@axis.com>

[ Upstream commit 3291c51d4684d048dd2eb91b5b65fcfdaf72141f ]

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 <waqar.hameed@axis.com>
Link: https://patch.msgid.link/bcf3a23b5187df0bba54a8c8fe09f8b8a0031dee.1766268280.git.waqar.hameed@axis.com
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
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 e9b5f42837729..e9cb06daecea9 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);
--
2.51.0