Re: xend crash at startup

[Guillaume Rousse <Guillaume.Rousse@inria.fr>]

Guillaume Rousse wrote:
> xend crashes at startup with following stack trace:
> ...
> File "/usr/lib64/python/xen/xend/XendPIF.py", line 68, in
> linux_get_phy_ifaces
>     phy_ifaces.append((name, int(mtu), bridged_mac))
> UnboundLocalError: local variable 'bridged_mac' referenced before assignment
> 
> The simple patch attached below prevent the crash, and allow xend to
> start normally.
> 
> It seems the crash happens when bridged_ifname is set to eth2, whereas
> eth2 doesn't appear in ip -o link show.
The problem surfaced again: xend start just crashes with previous message.

If I apply submitted patch, xend start just hang infinitly, and strace 
shows a futex issue:
Process 18743 attached - interrupt to quit
futex(0xcce634, FUTEX_WAIT, 1627, NULL) = 0
futex(0xcce608, FUTEX_WAKE, 1)          = 0
futex(0xcce660, FUTEX_WAKE, 1)          = 1
rt_sigaction(SIGPIPE, {SIG_IGN}, NULL, 8) = 0
futex(0xb18840, FUTEX_WAKE, 1)          = 0
futex(0xb18840, FUTEX_WAKE, 1)          = 0
rt_sigaction(SIGPIPE, {SIG_IGN}, {SIG_IGN}, 8) = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
write(19, "\2\0\0\0\0\0\0\0\304\0\0\0009\0\0\0", 16) = 16
write(19, "/vm/2cc873ba-81ea-4a3e-a6bc-15e9"..., 57) = 57
futex(0xcce634, FUTEX_WAIT, 1641, NULL) = 0
futex(0xcce608, FUTEX_WAKE, 1)          = 0
futex(0xcce660, FUTEX_WAKE, 1)          = 1
rt_sigaction(SIGPIPE, {SIG_IGN}, NULL, 8) = 0
futex(0xb18840, FUTEX_WAKE, 1)          = 0
rt_sigaction(SIGPIPE, {SIG_IGN}, {SIG_IGN}, 8) = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
write(19, "\7\0\0\0\0\0\0\0\304\0\0\0\2\0\0\0", 16) = 16
write(19, "T\0", 2)                     = 2
futex(0xcce634, FUTEX_WAIT, 1655, NULL) = 0
futex(0xcce608, FUTEX_WAKE, 1)          = 0
futex(0xcce660, FUTEX_WAKE, 1)          = 1
rt_sigaction(SIGPIPE, {SIG_IGN}, NULL, 8) = 0
futex(0xb18840, FUTEX_WAKE, 1)          = 0
rt_sigaction(SIGPIPE, {SIG_IGN}, {SIG_IGN}, 8) = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
write(19, "\6\0\0\0\0\0\0\0\0\0\0\0\1\0\0\0", 16) = 16
write(19, "\0", 1)                      = 1
futex(0xcce634, FUTEX_WAIT, 1669, NULL) = 0
futex(0xcce608, FUTEX_WAKE, 1)          = 0
futex(0xcce660, FUTEX_WAKE, 1)          = 1
rt_sigaction(SIGPIPE, {SIG_IGN}, NULL, 8) = 0
futex(0xb18840, FUTEX_WAKE, 1)          = 0
rt_sigaction(SIGPIPE, {SIG_IGN}, {SIG_IGN}, 8) = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL)    = 0
write(19, "\2\0\0\0\0\0\0\0\313\0\0\0009\0\0\0", 16) = 16
write(19, "/vm/2cc873ba-81ea-4a3e-a6bc-15e9"..., 57) = 57
futex(0xcce634, FUTEX_WAIT, 1683, NULL) = 0
futex(0xcce608, FUTEX_WAKE, 1)          = 0
futex(0xcce660, FUTEX_WAKE, 1)          = 1
rt_sigaction(SIGPIPE, {SIG_IGN}, NULL, 8) = 0
futex(0xb18840, FUTEX_WAKE, 1)          = 0
futex(0xb18840, FUTEX_WAKE, 1)          = 0
rt_sigaction(SIGPIPE, {SIG_IGN}, {SIG_IGN}, 8) = 0
futex(0xcce660, FUTEX_WAIT, 2, NULL <unfinished ...>

It may be related to the fact I had to use kill -9 on processus 
resulting from previous run, tough.
-- 
Guillaume Rousse
Moyens Informatiques - INRIA Futurs
Tel: 01 69 35 69 62