On two of my machines, I can get login to segfault. Is this expected? To each of the prompts, I just type control-D [hugh@redex ~]$ login login: login: login: Segmentation fault [hugh@redex ~]$ This behaviour was observed on F7 x86_64 and on FC5 i386. The last things in an strace: open("/etc/passwd", O_RDONLY) = 5 fcntl(5, F_GETFD) = 0 fcntl(5, F_SETFD, FD_CLOEXEC) = 0 fstat(5, {st_mode=S_IFREG|0644, st_size=1885, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x2aaab0746000 read(5, "root:x:0:0:root:/root:/bin/bash\n"..., 4096) = 1885 --- SIGSEGV (Segmentation fault) @ 0 (0) ---