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power: supply: act8945a: Fix use-after-free in power_supply_changed()

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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: a09209acd6 ("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>
This commit is contained in:
Waqar Hameed 2025-12-20 23:35:59 +01:00 • committed by Sebastian Reichel
parent c4af8a98bb
commit 3291c51d46
1 changed files with 8 additions and 8 deletions
Download patch file Download diff file Expand all files Collapse all files

16
drivers/power/supply/act8945a_charger.c
View file

@ -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);