CVE-2022-49580: Concurrent Execution using Shared Resource with Improper Synchronization

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

ipv4: Fix a data-race around sysctl_fib_multipath_use_neigh.

While reading sysctl_fib_multipath_use_neigh, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.