CVE-2026-64525 xfrm: move policy_bydst RCU sync from per-netns .exit to .pre_exit

In the Linux kernel, the following vulnerability has been resolved: xfrm: move policybydst RCU sync from per-netns .exit to .preexit The struct pernetoperations docstring in include/net/netnamespace.h explicitly warns against blocking RCU primitives in .exit handlers: Exit methods using blocking...