kern/55194: NetBSD 9.0/amd64 panics when rebooting with large tmpfs filesystems

[john%ziaspace.com@localhost]

>Number:         55194
>Category:       kern
>Synopsis:       NetBSD 9.0/amd64 panics when rebooting with large tmpfs filesystems
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Apr 21 19:45:00 +0000 2020
>Originator:     John Klos
>Release:        NetBSD 9.0
>Organization:
	
>Environment:
	
	
System: NetBSD daisy.zia.io 9.0 NetBSD 9.0 (GENERIC) #0: Fri Feb 14 00:06:28 UTC 2020  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:
	
While testing a clean NetBSD 9.0 install on an amd64 system with 64 gigs, I 
created several tmpfs mounts for a full build of NetBSD's dest, obj, tools 
and tmp directories. After running builds in a loop for several hours, I
ran a "shutdown -r now" and the system panicked:

[ 30428.9054821] Mutex error: mutex_vector_enter,564: locking against myself

[ 30428.9955221] lock address : 0xffff81dcd0ba14c0
[ 30429.0455430] current cpu  :                 10
[ 30429.0955644] current lwp  : 0xffff81db319f9120
[ 30429.1555893] owner field  : 0xffff81db319f9120 wait/spin:                0/0

[ 30429.2456293] panic: lock error: Mutex: mutex_vector_enter,564: locking against myself: lock 0xffff81dcd0ba14c0 cpu 10 lwp 0xffff81db319f9120
[ 30429.3956942] cpu10: Begin traceback...
[ 30429.4357120] vpanic() at netbsd:vpanic+0x160
[ 30429.4957393] snprintf() at netbsd:snprintf
[ 30429.5457592] lockdebug_abort() at netbsd:lockdebug_abort+0xee
[ 30429.6157896] mutex_vector_enter() at netbsd:mutex_vector_enter+0x364
[ 30429.6858206] uvm_fault_internal() at netbsd:uvm_fault_internal+0xa55
[ 30429.7658546] trap() at netbsd:trap+0x61e
[ 30429.8158764] --- trap (number 6) ---
[ 30429.8558942] 7f7f67a05156:
[ 30429.8859073] cpu10: End traceback...

[ 30429.9359300] dumping to dev 0,1 (offset=139007, size=16759590):
[ 30430.0059596] dump 4704
...

>How-To-Repeat:
	
>Fix:
	

>Unformatted: