In the Linux kernel, the following vulnerability has been resolved: power: supply: act8945a: Fix...

In the Linux kernel, the following vulnerability has been resolved:

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.