[Pkg-xen-devel] Bug#678723: i got same and found the reson

[Peter Pang]

i just found a bug from xapi code network_utils.ml:


 let is_physical name =

 try

 let link = Unix.readlink (getpath name "device") in

 (* filter out device symlinks which look like
/../../../devices/xen-backend/vif- *)

 not(List.mem "xen-backend" (String.split '/' link))

 with _ -> false


i use xcp + ubuntu 12.04, in my /sys/class/net/  dir it looks like:




drwxr-xr-x  2 root root 0 Oct  4 17:02 ./

drwxr-xr-x 46 root root 0 Oct  4 17:02 ../

lrwxrwxrwx  1 root root 0 Oct  4 17:02 eth0 ->
../../devices/pci0000:00/0000:00:01.0/0000:01:00.0/net/eth0/

lrwxrwxrwx  1 root root 0 Oct  4 17:02 eth1 ->
../../devices/pci0000:00/0000:00:01.0/0000:01:00.1/net/eth1/

lrwxrwxrwx  1 root root 0 Oct  4 17:02 lo -> ../../devices/virtual/net/lo/

lrwxrwxrwx  1 root root 0 Oct  4 19:05 tap9.0 ->
../../devices/virtual/net/tap9.0/

lrwxrwxrwx  1 root root 0 Oct  5 11:11 vif10.0 ->
../../devices/vif-10-0/net/vif10.0/

lrwxrwxrwx  1 root root 0 Oct  5 11:54 vif11.0 ->
../../devices/vif-11-0/net/vif11.0/

lrwxrwxrwx  1 root root 0 Oct  5 11:54 vif12.0 ->
../../devices/vif-12-0/net/vif12.0/

lrwxrwxrwx  1 root root 0 Oct  4 17:28 vif5.0 ->
../../devices/vif-5-0/net/vif5.0/

lrwxrwxrwx  1 root root 0 Oct  4 19:05 vif9.0 ->
../../devices/vif-9-0/net/vif9.0/

lrwxrwxrwx  1 root root 0 Oct  4 17:02 xenbr0 ->
../../devices/virtual/net/xenbr0/

lrwxrwxrwx  1 root root 0 Oct  4 17:02 xenbr1 ->
../../devices/virtual/net/xenbr1/



so , there is no subdir or symlink like "xen-backend", each device will be
think as real physical device and always return true from that function.


this bug will happen when ur dom0 reboot from a crash (some instance does
not released when crash happen), there will have a lots of bridge like
"brvif..."


thanks.
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