Startup/Mounting fails because "No free loop devices"

Question

When I switched on my laptop, I suddenly could not log in anymore. Everything was working fine until then, I was not messing with any settings.

When I enter my password on the (gnome) login screen, the screen just reloads.

I can log in on a tty console, but I get the error

Fedora Linux 36 (Thirty Six) Kernel 6.2,15-188.fc36.>86_64 on an >86_64 (tty2)

thinkpad login: ga325
Password: 
(mount.c:68): Messages from underlying mount program:
(mount.c:72): No free loop device 
(mount.c:72): (crypto-c:318): Error: no free loop devices 
(pam_mount.c:522): mount of /scratch/crypt/home-ga325.luks failed 
Last login: Wed Sep 11 28:41:31 on tty5
--- ga325: /scratch/users/ga325: change directory failed: Permission denied
Logging in with home = "/"
-bash: /scratch/users/ga325/.bash_profile: Permission denied

My home dir is shown as completely empty. The luks file still exists and is large (180GB).

Debugging info:

There are five loop devices that are all taken up by snap apps, see here:

df -h:

Furthermore, ls -l /var/lib/snapd/snaps shows five .snap files (corresponding to the loop devices) and that have all been touched last week. I snap installed and uninstalled Spotify last week, so this may have caused it.

The following outputs may be helpful for debugging:

cat /etc/fstab:

journalctl -xe:

start job for unit session-2.scope has finished successfully.
The job identifier is 3128 
22:48:11 thinkpad login[1795]: pam_unix(login:session): session opened for user ga325(uid=217589) by LOGIN(uid=0) 
22:48:11 thinkpad login[1795]: pam_sss(login:session): Request to sssd failed. Conect ion refused 
22:48:11 thinkpad audit[1795]: AUC avc: denied ( getattr ) for pid=1795 com="login" path=" /run/mount/utab" dev="tr
22:48:11 thinkpad audit[17951: AUC avc: denied ( read ) for pid=1795 com="login" name="utab" dev="tmpfs" ino=696 s 
22:48:11 thinkpad audit[1795]: AUC avc: denied ( open ) for pid=1795 com="login" path="/run/mount /utab" dev="tmpf: 
22:48:11 thinkpad audit[1873]: AUC avc: denied ( execute ) for pid=1873 com="login" name="mount .crypt" dev="mmebi 
22:48:11 thinkpad audit[1873]: AUC avc: denied ( entrypoint ) for pid=1873 comm="login" path="/usr/sbin/mount .cryp 
22:48:11 thinkpad login[17951: (mount .c:68): Messages from underlying mount program: 
22:48:11 thinkpad login[1795]: (mount.c:72): No free loop device 
22:48:11 thinkpad login[1795]: (mount.c:72): (crypto.c:310): Error: no free loop devices 
22:48:11 thinkpad login[1795]: (pam_mount.c:522): mount of /scratch/crypt/home-ga325.luks failed 
22:48:11 thinkpad audit[1795]: USER_START pid=1795 uid=0 auid=217589 ses=2 sub,j=system_u:system_r: local_login_t:s8-s8 
22:48:11 thinkpad audit[1795]: CRED_REFR pid=1795 uid=0 auid=217589 ses=2 sub j=system_u:system_r: local_login_t:s8-s8: 
22:48:11 thinkpad audit[1795]: USER_LOGIN pid=1795 uid=0 auid=217589 ses=2 subj-system_u:system_r: local_login_t:s8-s8 
22:48:11 thinkpad login[1795]: LOGIN ON tty2 BY ga325
22:48:11 thinkpad setroubleshoot[1308]: SELinux is preventing gnome-shell from read access on the lnk_file /scratch/l

service sssd status:

Questions:

• Is this an sssd problem or a mounting problem?
• How to debug/fix it?
• Can I recover my data from just the luks file?

Answer 1

sudo dnf remove snapd seemed to have solved the problem.

At first I tried clearing up space in dev/nvme0n1p4 which let me login again, but the problem came back on the next login.

So I tried sudo dnf remove snapd which seemed to have worked.

The new output of df -h is

Filesystem                                   Size  Used Avail Use% Mounted on
devtmpfs                                     4.0M     0  4.0M   0% /dev
tmpfs                                        7.8G     0  7.8G   0% /dev/shm
tmpfs                                        3.2G  2.2M  3.1G   1% /run
/dev/nvme0n1p2                                96G   50G   42G  55% /
/dev/nvme0n1p4                               357G  197G  142G  59% /scratch
/dev/nvme0n1p1                               260M   22M  239M   9% /boot/efi
tmpfs                                        7.8G   16K  7.8G   1% /tmp
tmpfs                                        1.6G  4.1M  1.6G   1% /run/user/217589
/dev/mapper/_scratch_crypt_home_ga325_luks   177G   60G  108G  36% /scratch/users/ga325