Snap does not work with kernel 6.8

[chainofflowers]

After updating to 6.8 series, snapd cannot use squashfs anymore.

```
$ snap install hello-world
error: system does not fully support snapd: cannot mount squashfs image using "squashfs": -----
       mount: /tmp/syscheck-mountpoint-4204491601: /dev/loop0 already mounted or mount point busy.

       dmesg(1) may have more information after failed mount system call.

       -----
```

`dmesg`does not give any hint: no new lines are outputted by it when running the failed `snap install` command.
The squashfs module is correctly loaded and I can use it to mount squashfs filesystems without issues.

It still works well with kernel 6.7.10.

I tried on two different computers, both x86_64 running Manjaro: same issue.

[Zygmunt Krynicki (zyga)]

It looks like Manjaro kernel dropped support for squashfs? I will reach out and see if this can be addressed.

[Zygmunt Krynicki (zyga)]

I misread the error. It looks like something else is going on here.

Dear reporter, can you please provide the output of:

cat /proc/self/mountinfo

[chainofflowers (whatifgodwasoneofus)]

UPDATE: It is working again with kernel 6.8.3

[Omid Farhang (omidfarhang)]

I'm using Kernel 6.8.4 (Manjaro) and suffering exact same problem

$ cat /proc/self/mountinfo

```
24 29 0:22 / /proc rw,nosuid,nodev,noexec,relatime shared:5 - proc proc rw
25 29 0:23 / /sys rw,nosuid,nodev,noexec,relatime shared:6 - sysfs sys rw
26 29 0:5 / /dev rw,nosuid,relatime shared:2 - devtmpfs dev rw,size=8149000k,nr_inodes=2037250,mode=755,inode64
27 29 0:24 / /run rw,nosuid,nodev,relatime shared:12 - tmpfs run rw,mode=755,inode64
28 25 0:25 / /sys/firmware/efi/efivars rw,nosuid,nodev,noexec,relatime shared:7 - efivarfs efivarfs rw
29 1 8:34 / / rw,noatime shared:1 - ext4 /dev/sdc2 rw
30 25 0:6 / /sys/kernel/security rw,nosuid,nodev,noexec,relatime shared:8 - securityfs securityfs rw
31 26 0:26 / /dev/shm rw,nosuid,nodev shared:3 - tmpfs tmpfs rw,inode64
32 26 0:27 / /dev/pts rw,nosuid,noexec,relatime shared:4 - devpts devpts rw,gid=5,mode=620,ptmxmode=000
33 25 0:28 / /sys/fs/cgroup rw,nosuid,nodev,noexec,relatime shared:9 - cgroup2 cgroup2 rw,nsdelegate,memory_recursiveprot
34 25 0:29 / /sys/fs/pstore rw,nosuid,nodev,noexec,relatime shared:10 - pstore pstore rw
35 25 0:30 / /sys/fs/bpf rw,nosuid,nodev,noexec,relatime shared:11 - bpf bpf rw,mode=700
36 24 0:31 / /proc/sys/fs/binfmt_misc rw,relatime shared:13 - autofs systemd-1 rw,fd=37,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=3226
37 26 0:20 / /dev/mqueue rw,nosuid,nodev,noexec,relatime shared:14 - mqueue mqueue rw
38 25 0:7 / /sys/kernel/debug rw,nosuid,nodev,noexec,relatime shared:15 - debugfs debugfs rw
39 26 0:32 / /dev/hugepages rw,nosuid,nodev,relatime shared:16 - hugetlbfs hugetlbfs rw,pagesize=2M
40 25 0:12 / /sys/kernel/tracing rw,nosuid,nodev,noexec,relatime shared:17 - tracefs tracefs rw
60 25 0:34 / /sys/kernel/config rw,nosuid,nodev,noexec,relatime shared:18 - configfs configfs rw
41 25 0:33 / /sys/fs/fuse/connections rw,nosuid,nodev,noexec,relatime shared:19 - fusectl fusectl rw
42 29 7:0 / /var/lib/snapd/snap/bare/5 ro,nodev,relatime shared:20 - squashfs /dev/loop0 ro,errors=continue,threads=single
43 29 7:1 / /var/lib/snapd/snap/core18/2812 ro,nodev,relatime shared:21 - squashfs /dev/loop1 ro,errors=continue,threads=single
44 29 7:2 / /var/lib/snapd/snap/core20/2105 ro,nodev,relatime shared:22 - squashfs /dev/loop2 ro,errors=continue,threads=single
45 29 7:3 / /var/lib/snapd/snap/core20/2182 ro,nodev,relatime shared:23 - squashfs /dev/loop3 ro,errors=continue,threads=single
46 29 7:4 / /var/lib/snapd/snap/core22/1033 ro,nodev,relatime shared:24 - squashfs /dev/loop4 ro,errors=continue,threads=single
47 29 7:5 / /var/lib/snapd/snap/gnome-3-28-1804/198 ro,nodev,relatime shared:25 - squashfs /dev/loop5 ro,errors=continue,threads=single
48 29 7:6 / /var/lib/snapd/snap/core22/1122 ro,nodev,relatime shared:26 - squashfs /dev/loop6 ro,errors=continue,threads=single
49 29 7:8 / /var/lib/snapd/snap/gnome-3-38-2004/143 ro,nodev,relatime shared:27 - squashfs /dev/loop8 ro,errors=continue,threads=single
50 29 7:7 / /var/lib/snapd/snap/gnome-42-2204/172 ro,nodev,relatime shared:28 - squashfs /dev/loop7 ro,errors=continue,threads=single
51 29 7:10 / /var/lib/snapd/snap/gtk-common-themes/1535 ro,nodev,relatime shared:29 - squashfs /dev/loop10 ro,errors=continue,threa...

[Adyel Ullahil Mamun (adyel)]

I am also facing the same issue on 8 April 2024 with Manjaro Gnome (6.8.4-1-MANJARO)

===========================================================================================================

➜ ~ uname --all
Linux adyel-linux 6.8.4-1-MANJARO #1 SMP PREEMPT_DYNAMIC Thu Apr 4 20:38:32 UTC 2024 x86_64 GNU/Linux

===========================================================================================================
➜ ~ cat /proc/self/mountinfo
24 30 0:22 / /proc rw,nosuid,nodev,noexec,relatime shared:5 - proc proc rw
25 30 0:23 / /sys rw,nosuid,nodev,noexec,relatime shared:6 - sysfs sys rw
26 30 0:5 / /dev rw,nosuid,relatime shared:2 - devtmpfs dev rw,size=12237548k,nr_inodes=3059387,mode=755,inode64
27 30 0:24 / /run rw,nosuid,nodev,relatime shared:12 - tmpfs run rw,mode=755,inode64
28 25 0:25 / /sys/firmware/efi/efivars rw,nosuid,nodev,noexec,relatime shared:7 - efivarfs efivarfs rw
29 26 0:26 / /dev/pts rw,nosuid,noexec,relatime shared:3 - devpts devpts rw,gid=5,mode=620,ptmxmode=000
30 1 0:27 /@ / rw,relatime shared:1 - btrfs /dev/sda2 rw,lazytime,compress=zstd:3,ssd,discard=async,space_cache=v2,subvolid=256,subvol=/@
31 25 0:6 / /sys/kernel/security rw,nosuid,nodev,noexec,relatime shared:8 - securityfs securityfs rw
32 26 0:30 / /dev/shm rw,nosuid,nodev shared:4 - tmpfs tmpfs rw,inode64
33 25 0:31 / /sys/fs/cgroup rw,nosuid,nodev,noexec,relatime shared:9 - cgroup2 cgroup2 rw,nsdelegate,memory_recursiveprot
34 25 0:32 / /sys/fs/pstore rw,nosuid,nodev,noexec,relatime shared:10 - pstore pstore rw
35 25 0:33 / /sys/fs/bpf rw,nosuid,nodev,noexec,relatime shared:11 - bpf bpf rw,mode=700
36 24 0:34 / /proc/sys/fs/binfmt_misc rw,relatime shared:13 - autofs systemd-1 rw,fd=36,pgrp=1,timeout=0,minproto=5,maxproto=5,direct,pipe_ino=9256
37 25 0:7 / /sys/kernel/debug rw,nosuid,nodev,noexec,relatime shared:16 - debugfs debugfs rw
38 26 0:20 / /dev/mqueue rw,nosuid,nodev,noexec,relatime shared:15 - mqueue mqueue rw
39 26 0:35 / /dev/hugepages rw,nosuid,nodev,relatime shared:14 - hugetlbfs hugetlbfs rw,pagesize=2M
40 25 0:12 / /sys/kernel/tracing rw,nosuid,nodev,noexec,relatime shared:17 - tracefs tracefs rw
41 25 0:36 / /sys/kernel/config rw,nosuid,nodev,noexec,relatime shared:18 - configfs configfs rw
42 25 0:37 / /sys/fs/fuse/connections rw,nosuid,nodev,noexec,relatime shared:19 - fusectl fusectl rw
45 30 0:27 /@home /home rw,relatime shared:69 - btrfs /dev/sda2 rw,lazytime,compress=zstd:3,ssd,discard=async,space_cache=v2,subvolid=257,subvol=/@home
46 30 0:27 /@cache /var/cache rw,relatime shared:72 - btrfs /dev/sda2 rw,lazytime,compress=zstd:3,ssd,discard=async,space_cache=v2,subvolid=258,subvol=/@cache
47 30 0:27 /@log /var/log rw,relatime shared:75 - btrfs /dev/sda2 rw,lazytime,compress=zstd:3,ssd,discard=async,space_cache=v2,subvolid=259,subvol=/@log
54 30 0:43 / /tmp rw,noatime shared:78 - tmpfs tmpfs rw,inode64
57 30 8:1 / /boot/efi rw,relatime shared:81 - vfat /dev/sda1 rw,fmask=0077,dmask=0077,codepage=437,iocharset=ascii,shortname=mixed,utf8,errors=remount-ro
216 27 0:67 / /run/user/1000 rw,nosuid,nodev,relatime shared:655 - tmpfs tmpfs rw,size=2454948k,nr_inodes=613737,mode=700,uid=1000,gid=1000,inode64
573 216 0:68 / /run/user/100...