Urbackupsrv crashes on Ubuntu 20.04

Hello,
yesterday I upgraed my Ubuntu 18.04.4 to Ubuntu 20.04 with urbackup installed from the ppa.
I noticed that urbackupsrv is not running and started analysing. Since there is no 20.04 build on the PPA, I uninstalled urbackup and reinstalled it from the OpenSuse build service.

Running it manually starts well, but suddenly crashes with a Segmentation fault:

2020-04-29 16:46:42: Starting HTTP-Server on port 55414
2020-04-29 16:46:42: HTTP: Server started up successfully!
2020-04-29 16:46:42: SQLite: recovered 432 frames from WAL file /var/urbackup/backup_server.db-wal code: 283
2020-04-29 16:46:42: SQLite: recovered 12904 frames from WAL file /var/urbackup/backup_server_files.db-wal code: 283
2020-04-29 16:46:42: SQLite: recovered 18758 frames from WAL file /var/urbackup/backup_server_link_journal.db-wal code: 283
2020-04-29 16:46:42: SQLite: recovered 30273 frames from WAL file /var/urbackup/backup_server_links.db-wal code: 283
2020-04-29 16:46:42: SQLite: recovered 3 frames from WAL file /var/urbackup/backup_server_settings.db-wal code: 283
2020-04-29 16:46:42: SQLite: recovered 432 frames from WAL file /var/urbackup/backup_server.db-wal code: 283
2020-04-29 16:46:42: SQLite: recovered 3 frames from WAL file /var/urbackup/backup_server_settings.db-wal code: 283
2020-04-29 16:46:42: SQLite: recovered 12904 frames from WAL file /var/urbackup/backup_server_files.db-wal code: 283
2020-04-29 16:46:42: SQLite: recovered 30273 frames from WAL file /var/urbackup/backup_server_links.db-wal code: 283
2020-04-29 16:46:43: SQLite: recovered 18758 frames from WAL file /var/urbackup/backup_server_link_journal.db-wal code: 283
2020-04-29 16:46:43: Started UrBackup…
2020-04-29 16:46:43: Removing temporary files…
2020-04-29 16:46:43: Recreating temporary folder…
TEST FAILED: guestmount is missing (libguestfs-tools)
2020-04-29 16:46:43: Image mounting disabled: TEST FAILED: guestmount is missing (libguestfs-tools)
Testing for btrfs…
TEST FAILED: Creating test btrfs subvolume failed
Testing for zfs…
TEST FAILED: Dataset is not set via /etc/urbackup/dataset
2020-04-29 16:46:43: Backup destination cannot handle subvolumes and snapshots. Snapshots disabled.
2020-04-29 16:46:43: Reflink ioctl failed. errno=95
2020-04-29 16:46:43: Broadcasting on ipv4 interface em1 addr 192.168.2.100
2020-04-29 16:46:43: Broadcasting on ipv6 interface em1 addr fe80::3e4a:92ff:fe74:3124
2020-04-29 16:46:43: InternetService: Server started up successfully!
2020-04-29 16:46:43: UrBackup Server start up complete.
2020-04-29 16:46:43: Server started up successfully!
2020-04-29 16:46:43: Looking for old Sessions… 0 sessions
2020-04-29 16:46:43: Downloading version file…
2020-04-29 16:46:44: Downloading version file…
2020-04-29 16:46:44: Downloading server version info…
2020-04-29 16:46:44: Downloading dataplan database…
2020-04-29 16:47:14: New Backupclient: CLIENT1
2020-04-29 16:47:14: New Backupclient: CLIENT2
2020-04-29 16:47:14: New Backupclient: CLIENT3
2020-04-29 16:47:14: New Backupclient: CLIENT4
Segmentation fault (core dumped)

Any idea on how to debug this problem? Thanks

Edit: In your Wiki I found an instruction on how to provide debug-information with gdb. So here is the output: https://www.codepile.net/pile/JL4bwvmg

Could you install the debug symbols and rerun this? ( https://download.opensuse.org/repositories/home:/uroni/xUbuntu_20.04/amd64/urbackup-server-dbgsym_2.4.12.0-1_amd64.ddeb )

Of course, here you go: https://www.codepile.net/pile/pwGrMnVb

Hmm, can’t reproduce the problem and it seems to be easily reproducible… (just connect a Internet client)

So two ideas: Perhaps it is indeed your CPU (output of cat /proc/cpuinfo), or your ubuntu has a stale crypto++ lib (apt remove libcrypto++6 then install urbackup-server again…?)

Here is my /proc/cpuinfo https://www.codepile.net/pile/jWPgERM5
I would be surprised if its because of the cpu, with 16.04 and 18.04 I had no problems. I was running the same version of urbackup in 18.04 already before upgrading to 20.04

Reinstalling libcrypto++6 and urbackup-server didn’t help, same segfault.

I disabled my homes firewall rules to deny any access from the internet clients, urbackup is running now . including sucessfully doing backups in my home network. So just no backups of my internet clients for now…

I just had the same issue on upgrading from 18.04 to 20.04. Used to be working without any problems until the upgrade. Now, as soon as an Internet client connects, seg-fault and core-dump. Unfortunately, all my backup clients except one are Internet clients.

As a workaround, what works well, is running the urbackupsrv in the official Docker container. Internet clients can still connect in this case.