Just wanted to add I am also seeing this. Also wanted to note using checkrestart with -n (I wondered if not using lsof might produce different results) instead gave a python exception/backtrace.
-- % sudo lsof -n | grep -E 'DEL|deleted' | grep /lib/ mpv 2765 rjy DEL REG 8,2 2883672 /lib/x86_64-linux-gnu/libudev.so.1.6.7 mpv 2765 rjy DEL REG 8,2 2883608 /lib/x86_64-linux-gnu/libsystemd.so.0.19.1 mpv/termi 2765 2769 rjy DEL REG 8,2 2883672 /lib/x86_64-linux-gnu/libudev.so.1.6.7 mpv/termi 2765 2769 rjy DEL REG 8,2 2883608 /lib/x86_64-linux-gnu/libsystemd.so.0.19.1 mpv/lua 2765 2770 rjy DEL REG 8,2 2883672 /lib/x86_64-linux-gnu/libudev.so.1.6.7 mpv/lua 2765 2770 rjy DEL REG 8,2 2883608 /lib/x86_64-linux-gnu/libsystemd.so.0.19.1 mpv/cache 2765 2774 rjy DEL REG 8,2 2883672 /lib/x86_64-linux-gnu/libudev.so.1.6.7 mpv/cache 2765 2774 rjy DEL REG 8,2 2883608 /lib/x86_64-linux-gnu/libsystemd.so.0.19.1 mpv/demux 2765 2775 rjy DEL REG 8,2 2883672 /lib/x86_64-linux-gnu/libudev.so.1.6.7 mpv/demux 2765 2775 rjy DEL REG 8,2 2883608 /lib/x86_64-linux-gnu/libsystemd.so.0.19.1 mpv/ao 2765 2778 rjy DEL REG 8,2 2883672 /lib/x86_64-linux-gnu/libudev.so.1.6.7 mpv/ao 2765 2778 rjy DEL REG 8,2 2883608 /lib/x86_64-linux-gnu/libsystemd.so.0.19.1 inetd 3864 root DEL REG 8,2 2883608 /lib/x86_64-linux-gnu/libsystemd.so.0.19.1 sshd 3871 root DEL REG 8,2 2883608 /lib/x86_64-linux-gnu/libsystemd.so.0.19.1 login 4085 root DEL REG 8,2 3014687 /lib/x86_64-linux-gnu/security/pam_systemd.so apt 9909 rjy DEL REG 8,2 2883672 /lib/x86_64-linux-gnu/libudev.so.1.6.7 systemd 21060 rjy txt REG 8,2 1665760 2886230 /lib/systemd/systemd (deleted) systemd 21060 rjy DEL REG 8,2 2883672 /lib/x86_64-linux-gnu/libudev.so.1.6.7 systemd 21060 rjy DEL REG 8,2 2883762 /lib/systemd/libsystemd-shared-235.so (sd-pam 21061 rjy txt REG 8,2 1665760 2886230 /lib/systemd/systemd (deleted) (sd-pam 21061 rjy DEL REG 8,2 3014687 /lib/x86_64-linux-gnu/security/pam_systemd.so (sd-pam 21061 rjy DEL REG 8,2 2883672 /lib/x86_64-linux-gnu/libudev.so.1.6.7 (sd-pam 21061 rjy DEL REG 8,2 2883762 /lib/systemd/libsystemd-shared-235.so dbus-daem 29391 messagebus DEL REG 8,2 2883608 /lib/x86_64-linux-gnu/libsystemd.so.0.19.1 systemd-l 29392 root txt REG 8,2 219272 2886245 /lib/systemd/systemd-logind (deleted) systemd-l 29392 root DEL REG 8,2 2883672 /lib/x86_64-linux-gnu/libudev.so.1.6.7 systemd-l 29392 root DEL REG 8,2 2883762 /lib/systemd/libsystemd-shared-235.so % sudo checkrestart Found 0 processes using old versions of upgraded files % sudo checkrestart -n Traceback (most recent call last): File "/usr/sbin/checkrestart", line 798, in <module> main() File "/usr/sbin/checkrestart", line 157, in main toRestart = procfilescheck(blacklist = blacklist, excludepidlist = excludepidlist) File "/usr/sbin/checkrestart", line 435, in procfilescheck data = re.split('\s+', output.strip('\n'), 3) TypeError: a bytes-like object is required, not 'str' -- https://rjy.org.uk/