Description of problem:
start a guest with 28 disks ,then hot add 29th virtio disks, seg fault occurs

Version-Release number of selected component (if applicable):
# uname -r
2.6.18-264.el5
# rpm -q kvm
kvm-83-235.el5


How reproducible:
100%

Steps to Reproduce:
1.start guest with e1000 nic & 28 virtio disks (CLI will attached)
2.hot add the 29th virtio disks)
(qemu) pci_add pci_addr=auto storage file=/root/ll28,if=virtio
failed to add file=/root/ll28,if=virtio
(qemu) Segmentation fault (core dumped)

Actual results:

Program terminated with signal 11, Segmentation fault.
#0  qemu_get_clock (clock=0x8200000001)
    at /usr/src/debug/kvm-83-maint-snapshot-20090205/qemu/vl.c:1310
1310        switch(clock->type) {
(gdb) bt
#0  qemu_get_clock (clock=0x8200000001)
    at /usr/src/debug/kvm-83-maint-snapshot-20090205/qemu/vl.c:1310
#1  0x0000000000409515 in main_loop_wait (timeout=<value optimized out>)
    at /usr/src/debug/kvm-83-maint-snapshot-20090205/qemu/vl.c:4134
#2  0x000000000050111a in kvm_main_loop ()
    at /usr/src/debug/kvm-83-maint-snapshot-20090205/qemu/qemu-kvm.c:596
#3  0x000000000040e757 in main_loop (argc=93, argv=0x7fff0f664c28, 
    envp=<value optimized out>)
    at /usr/src/debug/kvm-83-maint-snapshot-20090205/qemu/vl.c:4157
#4  main (argc=93, argv=0x7fff0f664c28, envp=<value optimized out>)
    at /usr/src/debug/kvm-83-maint-snapshot-20090205/qemu/vl.c:6559

Expected results:
no segmentation fault .it prompts sth like  "could not add 29th disk"

Additional info: