bin/55821: tar can not extract base.tgz anymore (./dev/pts and mounted ptyfs)

[martin%NetBSD.org@localhost]

>Number:         55821
>Category:       bin
>Synopsis:       tar can not extract base.tgz anymore (./dev/pts and mounted ptyfs)
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Mon Nov 23 20:30:00 +0000 2020
>Originator:     Martin Husemann
>Release:        NetBSD 9.99.75
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD whoever-brings-the-night.aprisoft.de 9.99.75 NetBSD 9.99.75 (WHOEVER) #350: Fri Nov 6 06:38:30 CET 2020 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src/sys/arch/sparc64/compile/WHOEVER sparc64
Architecture: sparc64
Machine: sparc64
>Description:

On a system with ptyfs mounted on /dev/pts, try to update from the base set
after I added /dev/pts to the set:

# stat /dev/pts 
31489 2 dr-xr-xr-x 2 root wheel 0 512 "Nov 23 20:34:49 2020" "Nov 23 18:39:49 2020" "Nov 23 20:34:50 2020" "Nov 23 13:18:38 2020" 4096 1 0 /dev/pts
# tar tvzf /mnt/sets/base.tgz ./dev/pts
drwxr-xr-x  0 root   wheel       0 Nov 23 18:39 ./dev/pts

.. so it should be a no-op. However, a "tar xpzf base.tgz" complains:

./dev/pts: Can't set user=0/group=0 for dev/pts
tar: Error exit delayed from previous errors.


>How-To-Repeat:
s/a

>Fix:
Make tar skip this kind of "error" silently?