lib/48562: mount_tmpfs segfaults mounting "/var/shm" on evbmips-mips64el (LOONGSON)

[jdbaker%mylinuxisp.com@localhost]

>Number:         48562
>Category:       lib
>Synopsis:       mount_tmpfs segfaults mounting "/var/shm" on evbmips-mips64el 
>(LOONGSON)
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    lib-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Jan 31 21:05:00 +0000 2014
>Originator:     John D. Baker
>Release:        NetBSD/evbmips-6.99.30 (mips64el/LOONGSON)
>Organization:
>Environment:
NetBSD chalk.technoskunk.fur 6.99.30 NetBSD 6.99.30 (YEELOONG) #4: Thu Jan 30 
19:42:48 CST 2014  
sysop%verthandi.technoskunk.fur@localhost:/d0/build/current/obj/mips64el/sys/arch/evbmips/compile/YEELOONG
 evbmips

(Kernel config includes LOONGSON with additions for debugging and
root on NFS and SD card.)
>Description:
During the execution of the startup scripts on my Lemote YEELOONG
netbook (Model 8101b), mounting "/var/shm" fails as follows:

[...]
Mounting all filesystems...
mount: /var/shm: Segmentation fault
/etc/rc.d/mountall exited with code 1
[...]

Examining the core dump left behind ("/mount_tmpfs.core") shows:

GNU gdb (GDB) 7.6.1
Copyright (C) 2013 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 "mips64el--netbsd".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /sbin/mount_tmpfs...(no debugging symbols found)...done.
[New process 1]
Core was generated by `mount_tmpfs'.
Program terminated with signal 11, Segmentation fault.
#0  0x7865ae04 in __ltsf2 () from /lib/libc.so.12
(gdb) bt
#0  0x7865ae04 in __ltsf2 () from /lib/libc.so.12
#1  0x7861a05c in __fixsfdi () from /lib/libc.so.12
#2  0x78758334 in __fixunssfdi () from /lib/libgcc_s.so.1
#3  0x7861a084 in __fixsfdi () from /lib/libc.so.12
#4  0x78758334 in __fixunssfdi () from /lib/libgcc_s.so.1
#5  0x7861a084 in __fixsfdi () from /lib/libc.so.12
#6  0x78758334 in __fixunssfdi () from /lib/libgcc_s.so.1
#7  0x7861a084 in __fixsfdi () from /lib/libc.so.12
#8  0x78758334 in __fixunssfdi () from /lib/libgcc_s.so.1
#9  0x7861a084 in __fixsfdi () from /lib/libc.so.12
#10 0x78758334 in __fixunssfdi () from /lib/libgcc_s.so.1
[...]

the output was captured by piping to 'tee'.  The "bt" command
produced an endless (presumedly) stream of the same two lines
as shown in "#1" and "#2" above.
>How-To-Repeat:
Have "/var/shm" configured in "/etc/fstab" and boot evbmips-mips64el
system (ideally LOONGSON--particularly Lemote YEELOONG) with kernel
and userland built from sources after 201401292100Z.
>Fix: