Starting with commit v2.6.29-6609-g11d06b2a1e5658f448a308aa3beb97bacd64a940, personality syscall never fails to set the personality, but before commit v2.6.35-rc1-372-g485d527 it still could return an error. Starting with that commit, personality syscall never returns an error. * linux/*/syscallent.h: Set SYSCALL_NEVER_FAILS flag in personality syscall entries.