Hi Dexuan, I've spent some time with the logs and looking over the code and couldn't find any smoking gun. I start to wonder if it might just be a timing issue? Can you try one or two things for me: 1) run with the blk-mq I/O path for scsi by either enabling it a boot / module load time with the scsi_mod.use_blk_mq=Y option, or at compile time by enabling the CONFIG_SCSI_MQ_DEFAULT option. If that fails with the commit a blk-mq run before the commit would also be useful. 2) if possible run a VM config without the virtual CD-ROM drive - a lot of the scsi log chatter is about handling timeouts on the CD drive, so that might be able to isolate issues a bit better. Note that I'll be offline from this afternoon European time until Sunday night as I'm out in the mountains at a lodge without internet access, but this issue will be my priority once back.