I've managed to reproduce blktests block/009 failures with kdevops [0] on linux-next tag next-20210304 with a current failure rate average of 1/448 (3 counted failures so far). I've documented the failure on korg#212305 [1] and provide instructions on how to reproduce. The failure happens on KVM virtualized guests, for the host OS I am using debian testing, but the target kernel is linux-next. My personal suspicion is not on the block layer but on scsi_debug because this can fail: modprobe scsi_debug; rmmod scsi_debug This second issue may be a secondary separate issue, but I figured I'd mention it. To fix this later issue I've looked at ways to make scsi_debug_init() wait until its scsi devices are probed, however its not clear how to do this correctly. If someone has an idea let me know. If that fixes this issue then we know it was that. [0] https://github.com/mcgrof/kdevops [1] https://bugzilla.kernel.org/show_bug.cgi?id=212305 Luis
