Snaps do not work on Arch Linux kernel 5.4 or 5.5

No snaps whatsoever will launch on kernels 5.4 or the 5.5rc’s. When trying to launch them from a terminal, I get cannot self-bind mount /run/snapd/ns: Cannot allocate memory. I’ve seen this mentioned on other forums, but these were some time ago, and the problem has still not been fixed. They do work on Manjaro 5.4, but not 5.5. Manjaro’s forum mentioned something about a kernel configuration issue, but the Arch Wiki says to not post about snap or snapd issues on Official Arch support sites, but to come here.

snap version
snap    2.42.5-1
snapd   2.42.5-1
series  16
arch    -
kernel  5.5.0-rc4-3-tkg-pds
snap debug sandbox-features
apparmor:             kernel:caps kernel:domain kernel:file kernel:mount kernel:namespaces kernel:network_v8 kernel:policy kernel:ptrace kernel:query kernel:rlimit kernel:signal parser:unsafe policy:default support-level:partial
confinement-options:  classic devmode
dbus:                 mediated-bus-access
kmod:                 mediated-modprobe
mount:                freezer-cgroup-v1 layouts mount-namespace per-snap-persistency per-snap-profiles per-snap-updates per-snap-user-profiles stale-base-invalidation
seccomp:              bpf-actlog bpf-argument-filtering kernel:allow kernel:errno kernel:kill_process kernel:kill_thread kernel:log kernel:trace kernel:trap kernel:user_notif
udev:                 device-cgroup-v1 tagging

Haven’t noticed anything unusual on 5.4:

$ uname -a   
Linux galeon 5.4.8-arch1-1 #1 SMP PREEMPT Sat, 04 Jan 2020 23:46:18 +0000 x86_64 GNU/Linux
$ snap run hello-world
Hello World!

Can you switch to the distro kernel and check if that works for you?

Looks like the bind mount could be addressed by this patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9c95a278ba7ca3ccc111c165cc74cb23c744fc85 and should be fixed in 5.5rc5.

The patch was part of the PR for 5.5rc5 https://lore.kernel.org/lkml/cbec7335-39b8-6b7d-402b-a6dd467b492b@canonical.com/