man: command exited with status 4

Status changed to 'Confirmed' because the bug affects multiple users.

I have the same issue. How can I solve it?

Thank you!
Antonio

Please run:

  strace -f -o man.trace -s 1024 man man

... make sure it reproduces the same bug, and attach the resulting man.trace file to this bug report. Thanks.

Hi Colin,
Yes, running strace command has reproduced the bug.
Attaching the man.trace herewith.

I think it happens since upgraded from 16.04 to 18.04.

For me happens on Ubuntu 18.04 and Kernel 4.12. Switching to 4.15 it works as expected.

Thanks Lancillotto. It worked for me too :-)
I had had Kernel 4.10.2-041002. upgrading to 4.15.0-29 solved this issue.

I am happy to here this Deepack, but unfortunately, for many reasons, I have to rely on 4.12! :(

Switching to kernel 4.15 resolves also the problem for me.
But unfortunately i have some applications that need kernel version 4.9

Seems that problem in apparmor profile loading on older kernels.
I have the same issue on custom kernel 4.4, but with ubuntu kernel 4.15 everything ok.

Workaround for older kernels:
apt install apparmor-utils
aa-disable /usr/bin/man

Upstream Bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=889617

Great, it works for 4.12, thank you!

Worked on my pine64 but on the Rpi 3, OS at same level, it gives the following :'

sudo apt install apparmor-utils

Reading package lists... Done
Building dependency tree
Reading state information... Done
apparmor-utils is already the newest version (2.12-4ubuntu5.1).
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
[3]- Done url=https://www.topgear.com.ph/features/lifestyle/lenovo-amd-laptops-a1008-20181202
[5]+ Done cd=CAEYACoUMTA0MDYyMTQwMTQ3MTcxODkyNTEyHGM5OTdmNGFhNDY5YzIwOWY6Y28udWs6ZW46R0I
$
$ sudo aa-disable /usr/bin/man
Disabling /usr/bin/man.

ERROR: Cache read/write disabled: interface file missing. (Kernel needs AppArmor 2.4 compatibility patch.)
Warning: unable to find a suitable fs in /proc/mounts, is it mounted?
Use --subdomainfs to override.

Up shot man no still not working.

Any Help, ideas available anybody ?

Is groff installed?

apt install groff

Same problem here on a raspberry running volumio2.
We've run out of ideas here. Everything seems ok, yet still the result is:
 Manual page man(1) line ?/? (END) (press h for help or q to quit)
....

I think we want to backport changes from the below upload to fix this

man-db (2.8.1-1) unstable; urgency=medium

  * New upstream release.
  * Use stacked profiles for subprocesses so that AppArmor realises that
    they constitute a reduction in privileges and allows the transition even
    after a seccomp filter has been installed.
  * Build with seccomp again, now that it works in conjunction with
    AppArmor.
  * Breaks/Replaces manpages-tr (<< 1.0.5.1-3) (closes: #889805).

@xnox, that seems unlikely to be helpful since the version you quote is older than the one in bionic! The reference to Debian bug #889617 is probably not correct even though they have similar symptoms.

I don't recall fixing this particular problem in Debian, and we probably need to pull in an AppArmor expert to figure out what the problem is.

The duplicate bug has a "profile not found" syslog message which seems likely to be relevant; I suspect there's something going on in relation to man-db's use of stacked profiles.

Hello, I believe this issue can be addressed by backporting kernel commit 9fcf78cca198600b27c44b4e50f00f8af3927f17 to your kernel. (Possibly other changes are also necessary; this change may build upon earlier changes, and may be further modified by future changes.

Thanks

Can anybody recreate this issue with a 4.15 kernel from the official Ubuntu archive?