On 2/8/2019 8:07 PM, Sijmen J. Mulder wrote:
Hi,
I run OpenBSD (snapshots) in a KVM+QEMU VM on Debian 9 and use it over
SSH. Those SSH sessions stall almost without fail when there's a lot of
output.
Repro (or at least my set up):
1. Create a KVM+QMEU VM on Linux with virt-manager. I assigned two
cores and otherwise used defaults.
2. Install an OpenBSD snapshot.
3. In an SSH session, execute 'find /' until hang. I suspect other
large network transfers may result in the same.
Symptoms:
- SSH session stalls with no output, no echo, and no response to ^C.
- New communication (SSH, ping) cannot be established: "no route to
host"
- The serial console outputs "re0: watchdog timeout"
- From the serial code, pinging the host yields "ping: sendmsg: No
buffer space available"
Workaround:
'ifconfig re0 down; ifconfig re0 up' and a little patience fixes it.
Below, the VM's dmesg and its libvirt XML dump. After seeing the NFS
messages I unmounted the shares but the behaviour was the same.
Sijmen
Why rtl8139? It's the worst option available to KVM/QEMU. You would be much
better off with virtio or e1000 for the NIC.