Kernel 2.6.25.x needs iproute2-2.6.25.x, earlier versions i.e. iproute2-2.6.24 won't work properly with a 2.6.25 kernel, the kernel version must match iproute2 version (see upstream for further info). Since kernel 2.6.25.x is marked stable, iproute2-2.6.25.x is needed and iproute2-2.6.25.x will only compile with glibc-2.7.x and later. In order to keep the tree clean, it is required to: mark glibc-2.7 as stable mark iproute 2.6.25.x as stable
glibc-2.8 is stable, so ...