uninitialized variable ifpnext in netrain_switch function causes the panic.

Panic String "kernel memory fault"




 0 boot                 src/kernel/arch/alpha/machdep.c : 2725
   1 panic                src/kernel/bsd/subr_prf.c : 1616
   2 trap                 src/kernel/arch/alpha/trap.c : 2289
   3 _XentMM              src/kernel/arch/alpha/locore.s : 2242
   4 prf                  src/kernel/bsd/subr_prf.c : 821
   5 sprintf              src/kernel/bsd/subr_prf.c : 1146
   6 netrain_switch       src/kernel/net/netrain.c : 1768
   7 netrain_niff_event_handler  src/kernel/net/netrain.c : 662
   8 netrain_process_niff_event  src/kernel/net/netrain.c : 422
crash>

------------------- AND -------------

0 stop_secondary_cpu   src/kernel/arch/alpha/cpu.c : 1416
   1 panic                src/kernel/bsd/subr_prf.c : 1509
   2 event_timeout        src/kernel/arch/alpha/cpu.c : 2430
   3 printf               src/kernel/bsd/subr_prf.c : 1018
   4 panic                src/kernel/bsd/subr_prf.c : 1566
   5 trap                 src/kernel/arch/alpha/trap.c : 2289
   6 _XentMM              src/kernel/arch/alpha/locore.s : 2242
   7 prf                  src/kernel/bsd/subr_prf.c : 821
   8 sprintf              src/kernel/bsd/subr_prf.c : 1146
   9 netrain_switch       src/kernel/net/netrain.c : 1768
  10 netrain_ioctl        src/kernel/net/netrain.c : 2927
  11 ifioctl              src/kernel/net/if.c : 2815
  12 soo_ioctl            src/kernel/bsd/sys_socket.c : 648
  13 ioctl_base           src/kernel/bsd/sys_generic.c : 753
  14 syscall              src/kernel/arch/alpha/syscall_trap.c : 725
  15 _Xsyscall            src/kernel/arch/alpha/locore.s : 1885

