Comment 4 for bug 123773

I can also confirm this.

This error does not appear during ifdown.

ifup shows this in strace:

read(3, "lo=lo\neth0=eth0\neth1=eth1\n", 4096) = 26
fstat64(4, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb7f33000
read(3, "", 4096) = 0
write(4, "lo=lo\neth0=eth0\neth1=eth1\neth1:1"..., 40) = 40
close(4) = 0
munmap(0xb7f33000, 4096) = 0
rename("/var/run/network/.ifstate.tmp", "/var/run/network/ifstate") = 0
close(3) = 0
munmap(0xb7f34000, 4096) = 0
clone(child_stack=0, flags=CLONE_CHILD_CLEARTID|CLONE_CHILD_SETTID|SIGCHLD, child_tidptr=0xb7df0708) = 15673
waitpid(15673, SIOCSIFFLAGS: Cannot assign requested address
[{WIFEXITED(s) && WEXITSTATUS(s) == 0}], 0) = 15673
--- SIGCHLD (Child exited) @ 0 (0) ---

I see a child exit, but I don't see where it forked. Perhaps I am being blind here? I don't really know what the child was, and didn't catch PID 15673 in the act.....