The patch included in sys-kernel/gentoo-sources-3.2.1-r1 ($URL) doesn't modify any kernel files. Instead, it creates another patch file: /usr/src/linux-3.2.1-gentoo-r1/b/queue-3.2: proc-clean-up-and-fix-proc-pid-mem-handling.patch that contains the actual patch, which never gets applied.
*** This bug has been marked as a duplicate of bug 399243 ***