Try ping -f localhost as root it should be obvious: --- localhost ping statistics --- 1847 packets transmitted, 177 packets received, 90% packet loss round-trip min/avg/max = 0.9/42.4/84.9 ms 90% is bad...
Not a bug, you are flood pinging. Not every ping request will come back. You are hammering the networking code in the kernel, it can't keep up.
Actually Pavel is most likely using a recent 2.1 kernel. There is a known problem with the ping binary. Please look at: http://www.egroups.com/list/linux-kernel/77859.html http://www.egroups.com/list/linux-kernel/78066.html (If you don't know who Alexey Kuznetsov is, he did a _lot_ of TCP/IP work in the 2.1 kernels)
*** This bug has been marked as a duplicate of 213 ***