valgrind doesn't support the landlock syscalls. Can easily be reproduced running xz under valgrind:

$ valgrind -q xz --help > /dev/null
-160508- WARNING: unhandled amd64-linux syscall: 444
-160508- You may be able to write your own handler.
-160508- Read the file README_MISSING_SYSCALL_OR_IOCTL.
-160508- Nevertheless we consider this a bug. Please report
-160508- it at http://valgrind.org/support/bug_reports.html.

This is upstream https://bugs.kde.org/show_bug.cgi?id=489913 which already contains a (partial) patch.