early virtio console output is lost

[Michal Suchanek]

This is broken in git and reportedly in 2.5 through 2.7.

Running a Linux kernel which includes a testsuite in initrd sometimes produces no output.

Reportedly the console is sometimes not open when the early userspace tries to log output resulting in either the testsuite terminating early or not writing the output.

Workaround patch is here:

https://git.zx2c4.com/WireGuard/commit/?id=d2de8b0862a7fbb51a7f2f958d58f0efe4648259

reportedly you would get -EBADF there when no output is generated.

Also this reportedly happens with virtio console only, not virtio serial port.

It seems that the author of said testsuite did not report the problem so I write it down so it does not get lost.

test (in bash):

n=0 ; while [ $n -lt 100 ] && grep -m 1 -F "WireGuard Test Suite on Linux 4.8.6" <( /opt/qemu/bin/qemu-system-x86_64 -nodefaults -nographic -machine q35,accel=kvm -cpu host -smp 2 -m 64M -object rng-random,id=rng0,filename=/dev/urandom -device virtio-rng-pci,rng=rng0 -device virtio-serial,max_ports=2 -chardev stdio,id=stdio -device virtconsole,chardev=stdio -chardev file,id=status,path=result.txt -device virtserialport,chardev=status -monitor none -kernel wireguard-testing-harness-bzImage-e87cb2a7-145c-4985-907f-17e81fae329b -append "console=hvc0 initcall_debug=1 loglevel=7" ) ; do echo $n ; n=$(expr $n + 1) ; pkill -f wireguard ; done

This typically does 10-20 iterations but sometimes tens of iterations run without issue.

[Thomas Huth (th-huth)]

The QEMU project is currently considering to move its bug tracking to another system. For this we need to know which bugs are still valid and which could be closed already. Thus we are setting all older bugs to
"Incomplete" now.
If you still think this bug report here is valid, then please switch the state back to "New" within the next 60 days, otherwise this report will be marked as "Expired". Thank you and sorry for the inconvenience.

[Launchpad Janitor (janitor)]

[Expired for QEMU because there has been no activity for 60 days.]