CVE-2026-90392

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

bpf: Fix potential UAF when reading bpf link info

In bpf_link_show_fdinfo and bpf_link_get_info_by_fd, link->prog is
accessed without holding any locks. If the prog is concurrently replaced
via bpf_link_update, the old prog can be freed, leading to a potential
UAF issue.

Fix this by accessing link->prog under RCU protection to safely fetch
the pointer and guarantee its lifetime while reading its fields.