CVE-2025-22009

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

regulator: dummy: force synchronous probing

Sometimes I get a NULL pointer dereference at boot time in kobject_get() with the following call stack:

anatopregulatorprobe() devmregulatorregister() regulatorregister() regulatorresolvesupply() kobjectget()

By placing some extra BUGON() statements I could verify that this is raised because probing of the 'dummy' regulator driver is not completed ('dummyregulator_rdev' is still NULL).

In the JTAG debugger I can see that dummyregulatorprobe() and anatopregulatorprobe() can be run by different kernel threads (kworker/u4:*). I haven't further investigated whether this can be changed or if there are other possibilities to force synchronization between these two probe routines. On the other hand I don't expect much boot time penalty by probing the 'dummy' regulator synchronously.