"xm save" trouble -- deadlock?

[Gerd Knorr <kraxel@suse.de>]

   Hi,

"xm save" doesn't work for me, the command just blocks forever.  In the 
process list it looks like this:

  6567 ?        Ssl    0:00 python /usr/sbin/xend restart
  7978 ?        SL     0:00  \_ /usr/lib/xen/bin/xc_save 14 17 10 0 0 0

xc_save is blocked, in a write call to stderr:

   master-xen root /vm/ttylinux# strace -p7978
   Process 7978 attached - interrupt to quit
   write(2, "FNI 28 : [10000004,815] pte=2b92"..., 80 <unfinished ...>
   Process 7978 detached

stderr is a pipe to xend:

   master-xen root /vm/ttylinux# ll /proc/7978/fd/2
   l-wx------  1 root root 64 Nov  1 17:25 /proc/7978/fd/2 -> pipe:[40419]
   master-xen root /vm/ttylinux# ll /proc/*/fd/* | grep 40419
   lr-x------  1 root root 64 Nov  1 17:25 /proc/6567/fd/22 -> pipe:[40419]
   l-wx------  1 root root 64 Nov  1 17:25 /proc/7978/fd/2 -> pipe:[40419]

xend in turn doesn't read from the pipe but is waiting for some lock:

   master-xen root /vm/ttylinux# strace -p6567
   Process 6567 attached - interrupt to quit
   futex(0x8087370, FUTEX_WAIT, 0, NULL <unfinished ...>
   Process 6567 detached

Ideas anyone what is going on here?

   Gerd