In the Linux kernel, the following vulnerability has been resolved:
power: supply: pm8916_lbc: Fix use-after-free for extcon in IRQ handler
Using the `devm_` variant for requesting IRQ _before_ the `devm_`
variant for allocating/registering the `extcon` handle, means that the
`extcon` 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 `extcon` handle has been
freed, *but* just _before_ the corresponding unregistration of the IRQ
handler has run.
This will lead to the IRQ handler calling `extcon_set_state_sync()` with
a freed `extcon` handle. Which usually crashes the system or otherwise
silently corrupts the memory…
Fix this racy use-after-free by making sure the IRQ is requested _after_
the registration of the `extcon` handle.
