CVE-2024-42250

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

cachefiles: add missing lock protection when polling

Add missing lock protection in poll routine when iterating xarray, otherwise:

Even with RCU read lock held, only the slot of the radix tree is ensured to be pinned there, while the data structure (e.g. struct cachefiles_req) stored in the slot has no such guarantee. The poll routine will iterate the radix tree and dereference cachefiles_req accordingly. Thus RCU read lock is not adequate in this case and spinlock is needed here.