kern/52324: assertion "(target->prt_class == class)" failed: subr_psref.c", line 285

[tnn%NetBSD.org@localhost]

>Number:         52324
>Category:       kern
>Synopsis:       assertion "(target->prt_class == class)" failed: subr_psref.c", line 285
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Jun 22 19:40:00 +0000 2017
>Originator:     Tobias Nygren
>Release:        8.99.1 amd64
>Organization:
>Environment:
>Description:
I can reliably trigger this panic from userland by running a certain java application.

panic: kernel diagnostic assertion "(target->prt_class == class)" failed: file "/work/src/sys/kern/subr_psref.c", line 285 mismatched psref target class: 0x0 (ref) != 0xffffe400bfe0ed08 (expected)
fatal breakpoint trap in supervisor mode
trap type 1 code 0 rip 0xffffffff802249f5 cs 0x8 rflags 0x246 cr2 0x10020f000 ilevel 0x4 rsp 0xffffe40045b75b60
curlwp 0xffffe400beb28200 pid 533.2 lowest kstack 0xffffe40045b722c0
[0xffffffff802249f5->breakpoint][0xffffffff80226450->cpu_Debugger][0xffffffff80742474->db_panic][0xffffffff80990401->vpanic][0xffffffff80ce36b8->kern_assert][0xffffffff8099140b->psref_release][0xffffffff80a20d7e->if_put][0xffffffff806f4b38->ip6_ctloutput][0xffffffff80708380->udp6_ctloutput][0xffffffff806ea121->udp6_ctloutput_wrapper][0xffffffff809c286a->sosetopt][0xffffffff809c6ef2->sys_setsockopt][0xffffffff80250765->syscall]
dumping to dev 20,1 (offset=14682167, size=786319):

>How-To-Repeat:
I'll leave out the exact details since it might be possible for unprivileged userland to mess with the kernel if DIAGNOSTIC/DEBUG is not enabled. Ping me off-list for details.
>Fix:
A workaround seems to be to launch the program with -Djava.net.preferIPv4Stack=true.