bcache not working as expected with ramdisk as cache device

I was trying out bcache but i don't have an SSD so wanted to use free memory as a substitute. As ramdisk is listed in /proc/devices as block device i assumed this would work OK but with below simple test i can't get it working. This is on Ubuntu 15.10 with latest 4.5 kernel installed and i'm using the default /dev/ram devices as my SSD substitute. losetup -f dd if=/dev/zero of=/tmp/bcache_origin bs=1M count=200 losetup /dev/loop2 /tmp/bcache_origin make-bcache -B /dev/loop2 -C /dev/ram9 No error or output was given from make-bcache. At this point i expect for the new bcache device to be listed in below paths either by UUID or name but there is nothing. ls -al /sys/fs/bcache/ ls -al /sys/block/bcache* Here is outputs from cache-super-show for cache bcache-super-show /dev/ram9 sb.magic ok sb.first_sector 8 [match] sb.csum 53EDD9C169F73E1B [match] sb.version 0 [cache device] dev.label (empty) dev.uuid 2189aa3b-67e7-4296-bb25-6b5ba886befa dev.sectors_per_block 1 dev.sectors_per_bucket 1024 dev.cache.first_sector 1024 dev.cache.cache_sectors 130048 dev.cache.total_sectors 131072 dev.cache.ordered no dev.cache.discard no dev.cache.pos 0 dev.cache.replacement 0 [lru] cset.uuid 0a6b3824-72c1-489e-9d96-d976cb49e8a9 and origin bcache-super-show /dev/loop2 sb.magic ok sb.first_sector 8 [match] sb.csum ECBC84E42E6F52B9 [match] sb.version 1 [backing device] dev.label (empty) dev.uuid aff690a4-7ee1-4b62-85cc-ad41c775d7d8 dev.sectors_per_block 1 dev.sectors_per_bucket 1024 dev.data.first_sector 16 dev.data.cache_mode 0 [writethrough] dev.data.cache_state 0 [detached] cset.uuid 0a6b3824-72c1-489e-9d96-d976cb49e8a9 I also tried using loop devices for both but that failed even worse. Running below command results in nasty kernel BUG dump in dmesg. losetup -f dd if=/dev/zero of=/tmp/bcache_data bs=1M count=200 dd if=/dev/zero of=/tmp/bcache_cache bs=1M count=200 losetup /dev/loop5 /tmp/bcache_data losetup /dev/loop6 /tmp/bcache_cache make-bcache -B /dev/loop5 -C /dev/loop6 ll /sys/fs/bcache/ Has anyone successfully got a ramdisk to work as caching device with bcache ? Without any sort of stdout/err to indicate where it's failing i'm not sure if this is my miss-configuration or a bug. Thanks fLo