> On Thu, Apr 06, 2006 at 04:34:58PM +0400, Serge Goodenko wrote: > > the problem is when I ping any net1 host from any net0 host I get > > about 90% packet loss and 'tcpdump -x' started on router eth1 device > > shows the following packets (which are obviously corrupted): > > And the same pinging from net1 to net0?
yeah, it's absolutely symmetric - if pinging from net1 to net0 corruption occurs between router eth0 and net0. > > What version of UML? UML kernel version 2.6.13-4 with built-in UML running in SKAS3 mode. I don't know whether UML code itself has any versioning... host kernel is 2.6.13-15, if it matters.. ) > > Can you see where the corruption originates? I.e. tcpdump the > originating UML's eth0, if that's OK, check what's leaving the switch > (which you can do by attaching it to a host tap device, running it > -hub, and tcpdumping the tap device), etc. yes, I tried tcpdumping tap device as you said - the same result. a lot of 5a5a.. packets arrives at it. however, if I ping 192.168.1.1 from net0 it goes ok and 100% packets are replied. I have also tried to run tcpdump with '-e' option to see the source and dest mac addresses and it became clear that packets currupt when router sends them to net1 (before tcpdump shows it) but a fact that the corruption is generally accidental confuses me most... I also tried to send TCP messages using simple tcp client and server between net0 and net1 and the data always transmits ok (apparently due to tcp guarantees delivery) but these 5a5a packets still appear and therefore sometimes tcp transmission is very slow. > > The 0x5a5a pattern is kernel slab poisoning, BTW, so it looks like a > kernel is sending out a packet which had already been freed. > what makes kernel behave so is the biggest question for me now.... Serge MIPT Moscow, Russia ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
