Michael, with commit db7286b100b503ef80612884453bed53d74c9a16 (refs/bisect/skip-db7286b100b503ef80612884453bed53d74c9a16) vhost: use batched version by default plus commit 6bd262d5eafcdf8cdfae491e2e748e4e434dcda6 (HEAD, refs/bisect/bad) Revert "vhost/net: add an option to test new code" to make things compile (your next tree is not easily bisectable, can you fix that as well?). I get random crashes in my s390 KVM guests after reboot. Reverting both patches together with commit decd9b8 "vhost: use vhost_desc instead of vhost_log" to make it compile again) on top of linux-next-1218 makes the problem go away. Looks like the batched version is not yet ready for prime time. Can you drop these patches until we have fixed the issues? Christian