In the Linux kernel, the following vulnerability has been resolved:
cpufreq: imx6q: fix devres accumulation across driver rebind
imx6_soc_volt is allocated with devm_kcalloc(cpu_dev, …), where cpu_dev
is the CPU device from get_cpu_device(0). That device is never unbound, so
its devres list is never released, and imx6q_cpufreq_remove() does not free
the array either. Every probe therefore adds an allocation that stays for
the lifetime of the system.
Allocate against the platform device instead. Its devres is released when
the driver is unbound, which is exactly the lifetime the array wants:
imx6q_set_target() reads it, and nothing may reach that after
cpufreq_unregister_driver().
That makes the array actually go away on unbind, so also clear the
file-scope pointer in remove and on the failed-probe path, rather than
leave it pointing at memory devres is about to release.
Tested by rebinding the driver on qemu’s mcimx6ul-evk.
