> -----Original Message----- > From: Sitsofe Wheeler [mailto:sitsofe@xxxxxxxxx] > Sent: Tuesday, August 19, 2014 8:37 AM > To: KY Srinivasan > Cc: Greg Kroah-Hartman; Haiyang Zhang; devel@xxxxxxxxxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; Jason Wang; Daniel Borkmann; David S. > Miller; netdev@xxxxxxxxxxxxxxx > Subject: [hyperv] BUG at drivers/hv/channel.c:462 while changing MTU > > Now we get to the issue I've been meaning to report: changing the MTU of > a Hyper-V network interface while traffic is flowing through it triggers > a BUG. I've seen this happen on a variety of kernels but the trace below > is from 3.17.0-rc1. > > Steps to reproduce: > (Guests were customised Fedora 20 cloud images) > 1.On Hyper-V VM 1 run > iperf -s > 2. On Hyper-V VM 2 run > iperf -c <Hyper-V VM 1 host address> -t 200 > 3. On Hyper-V VM 2 run > ip link set dev eth0 mtu 9000 > > Expected results: > MTU of eth0 to be changed, packets to keep flowing or stop, interface to > be at alive enough to be reconfigured. > > Actual results: > Error messages on the console, eth0 winds up dead. > Thanks for the report. I tried changing mtu while iperf is running, but unable to reproduce it. I repeated the changing MTU test 10+ times, the link is stable, and passing traffic at ~8Gbps. Could you try a Distro without customization? I just want to narrow down the possible causes for it. Thanks, - Haiyang _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
