Enabling vsyscall on Debian

Introduction

If you are using one of the latest Debian versions, you may need to enable vsyscall which is disabled by default for some kernel versions, for example, for Debian 9 (Stretch) with kernel 4.18.x.bpo and Debian 10 (Buster) RC1 with kernel 4.19.0.

vsyscall is a mechanism that is used to accelerate certain system calls on Linux. It is required for the ONLYOFFICE Mail to work correctly. To run the ONLYOFFICE Mail Docker container and ensure ONLYOFFICE Mail works correctly, follow the instructions below.

Checking if vsyscall is disabled

To check whether vsyscall is disabled on your system, run the following command:

cat /proc/self/maps | egrep 'vdso|vsyscall'

The output will be similar to the following:

7fffccfcc000-7fffccfce000 r-xp 00000000 00:00 0                          [vdso]

or you'll see output like this:

7fffe03fe000-7fffe0400000 r-xp 00000000 00:00 0                          [vdso]
ffffffffff600000-ffffffffff601000 r-xp 00000000 00:00 0                  [vsyscall]

If you do not see a vsyscall mapping, add vsyscall=emulated to the kernel options in your bootloader, as described in the next step.

Enabling vsyscall

To enable vsyscall on your operating system, run the following commands:

echo 'GRUB_CMDLINE_LINUX_DEFAULT="vsyscall=emulate"' >> /etc/default/grub

This command enables vsyscall on system boot and adds this parameter to the /etc/default/grub file, which contains the main settings for the GRUB bootloader.

After modifying the /etc/default/grub file, update GRUB:

update-grub

Reboot the system:

reboot

Once the system has rebooted, proceed to the ONLYOFFICE Mail Docker version installation.