Zram on /tmp not mounting

I am trying using Zram on /tmp
I enabled the menuconfig entry on procd

However, I have :

# dmesg|grep -i zr
[    4.700305] zram: Added device: zram0
[    4.883963] zram0: detected capacity change from 0 to 16777216
[    4.938285] init: Can't mount /dev/zram0 on /tmp: No such device
[   17.131865] zram0: detected capacity change from 0 to 30408704
[   17.151568] Adding 29692k swap on /dev/zram0.  Priority:-2 extents:1 across:29692k SS

i.e. zram is working fine (here on swap), but /tmp seems not mounting

mount gives :

root@4g:~# mount
/dev/root on /rom type squashfs (ro,relatime)
devtmpfs on /rom/dev type devtmpfs (rw,relatime,size=29376k,nr_inodes=7344,mode=755)
proc on /proc type proc (rw,nosuid,nodev,noexec,noatime)
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,noatime)
tmpfs on /tmp type tmpfs (rw,nosuid,nodev,noatime)
/dev/mtdblock5 on /overlay type jffs2 (rw,noatime)
overlayfs:/overlay on / type overlay (rw,noatime,lowerdir=/,upperdir=/overlay/upper,workdir=/overlay/work)
tmpfs on /dev type tmpfs (rw,nosuid,relatime,size=512k,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,mode=600,ptmxmode=000)

Is there a specific point to pay attention to, to make it work ?

Thank you

Did you ever get this to work?

I'm having the same problem.

I do hope some core OpenWrt devs are reading this, but the procd option of mounting /tmp on a zram block device doesn't make any sense. Tmpfs is backed by anonymous memory, which can be swapped out at any time, if needed.

so nobody was able to mount /tmp via zram?

Nobody sane (i. e., who knows how Linux memory management works) would do it, because it makes no sense at all. That config option shouldn't even exist, I have pending patches for removing it. Use zram-swap.