kern/53763: truncated core files

[martin%NetBSD.org@localhost]

>Number:         53763
>Category:       kern
>Synopsis:       truncated core files
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Dec 06 09:15:00 +0000 2018
>Originator:     Martin Husemann
>Release:        NetBSD 8.99.26
>Organization:
The NetBSD Foundation, Inc.
>Environment:
System: NetBSD unpluged.duskware.de 8.99.26 NetBSD 8.99.26 (UNPLUGED) #213: Wed Dec 5 12:28:43 CET 2018 martin%seven-days-to-the-wolves.aprisoft.de@localhost:/work/src/sys/arch/evbarm/compile/UNPLUGED evbarm
Architecture: earm
Machine: evbarm
>Description:

On this machine named dumps core (sometimes). However, the core is not
usable:

unpluged:/home/martin # cd /etc/namedb/
unpluged:/etc/namedb # gdb named named.core 
GNU gdb (GDB) 8.0.1
Copyright (C) 2017 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "armv6--netbsdelf-eabi".
Type "show configuration" for configuration details.
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>.
Find the GDB manual and other documentation resources online at:
<http://www.gnu.org/software/gdb/documentation/>.
For help, type "help".
Type "apropos word" to search for commands related to "word"...
Reading symbols from named...Reading symbols from /usr/libdata/debug//usr/sbin/named.debug...done.
done.
"/etc/namedb/named.core" is not a core dump: File truncated
(gdb) q
unpluged:/etc/namedb # ll named.core 
-rw-------  1 root  wheel  52 Dec  5 13:17 named.core
unpluged:/etc/namedb # file named.core 
named.core: ELF 32-bit LSB core file, ARM, EABI5 version 1 (SYSV)


This is with root on NFS, enough space on the file system and no kernel
crash. However, the system was shutting down for a reboot when this happened:

Dec  5 13:17:57 unpluged syslogd[191]: Exiting on signal 15
Dec  5 13:19:41 unpluged syslogd[124]: restart
Dec  5 13:19:41 unpluged /netbsd: [ 701477.3670056] syncing disks... done

Still no good reason not to complete the core dump in time ;-)

>How-To-Repeat:
not sure, but may be reproducable here.

>Fix:
n/a