On 04/08/2020 16:34, Coly Li wrote: > On 2020/8/4 22:31, Johannes Thumshirn wrote: >> On 04/08/2020 16:23, Coly Li wrote: >>> This is the procedure to reproduce the panic, >>> # modprobe scsi_debug delay=0 dev_size_mb=2048 max_queue=1 >>> # losetup -f /dev/nvme0n1 --direct-io=on >>> # blkdiscard /dev/loop0 -o 0 -l 0x200 >> >> losetup -f /dev/sdX isn't it? >> > > In my case, I use a NVMe SSD as the backing device of the loop device. > Because I don't have a scsi lun. > > And loading scsi_debug module seems necessary, otherwise the discard > process just hang and I cannot see the kernel panic (I don't know why yet). OK, now that's highly interesting. Does it also happen if you back loop with a file? loop_config_discard() has different cases for the different backing devices/files. S
