c1700 IOS images start once and then fail to boot on second boot.

[grossmj]

Originally reported there: GNS3/gns3-gui#70

I ran some tests and it appears that the problem comes from the sparse memory feature.

To reproduce, start the hypervisor: dynamips -H 7200, telnet to it and paste the following commands. Any c1700 image should do. I suspect the same problem with c2600 images.

hypervisor working_dir "/tmp/"
vm create "R1" 1 c1700
vm set_sparse_mem "R1" 1
vm set_con_tcp_port "R1" 2001
vm set_ram "R1" 128
vm set_ios "R1" "/home/grossmj/GNS3/images/IOS/c1700-advsecurityk9-mz.124-25d.image"
vm start "R1"
vm stop "R1"
vm start "R1"

Dynamips will crash just after the restart and throw many error messages like this one:

PPC32: unknown opcode 0x00000000 at ia = 0x4d4
PowerPC Registers:
  $ 0 = 0x00000000  $ 1 = 0x80005fb8  $ 2 = 0x00000000  $ 3 = 0x00000000
  $ 4 = 0xf6000000  $ 5 = 0x00000000  $ 6 = 0x00000000  $ 7 = 0x00000000
  $ 8 = 0x00000000  $ 9 = 0xf6000000  $10 = 0x00000000  $11 = 0x00000003
  $12 = 0x00000000  $13 = 0x00000000  $14 = 0x00000000  $15 = 0x00000000
  $16 = 0x00000000  $17 = 0x00000000  $18 = 0x00000000  $19 = 0x00000000
  $20 = 0x00000000  $21 = 0x00000000  $22 = 0x00000000  $23 = 0x00000000
  $24 = 0x00000000  $25 = 0x00000000  $26 = 0x00000000  $27 = 0x00000000
  $28 = 0x00000000  $29 = 0xf6000000  $30 = 0x00000064  $31 = 0x4c61756e

  ia = 0x000004d4, lr = 0x803aa174
  cr = 0x00000002, msr = 0x00000000, xer = 0x00000000, dec = 0x00000000
  sprg[0] = 0x00000000, sprg[1] = 0x00000000
  sprg[2] = 0x00000000, sprg[3] = 0x00000000

  IRQ count: 0, IRQ false positives: 0, IRQ Pending: 0, IRQ Check: no
  Timer IRQ count: 0, pending: 0, timer drift: 0

  Device access count: 330

Everything works if you remove the set_sparse_mem command from the commands above.

[flaviojs]

Failed to reproduce with "c1710-bk9no3r2sy-mz.124-23.image" and the current master (f736133).

Maybe the root cause is already fixed? Give it another try.