7.99.42/Nov 2 panic: kernel diagnostic assertion "l->l_md.md_gc_ptp == NULL" failed

[Thomas Klausner <tk%giga.or.at@localhost>]

Hi!

Today I was running a bulk build and an idle syncthing
(net/syncthing). When I tried to quit syncthing using CTRL-C (which
worked once before on the same day), I got a kernel panic:

panic: kernel diagnostic assertion "l->l_md.md_gc_ptp == NULL" failed: file "/disk/6/archive/foreign/src/sys/arch/x86/x86/vm_machdep.c", line 262  WARNING: SPL NOT LOWERED ON SYSCALL 146 4 EXIT 81c27c08 6

dmesg on boot contained lots of spam at the start:

WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 233 4 EXIT 81c27c08 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 1 6 EXIT 0 7
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 233 4 EXIT 81c27c08 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 1 6 EXIT 0 7
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 233 4 EXIT 81c27c08 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
lwp_userret() at WARNING: SPL NOT LOWERED ON SYSCALL 1 6 EXIT 0 7
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 250 4 EXIT 81c27c08 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
netbsd:lwp_userret+0xf9
WARNING: SPL NOT LOWERED ON SYSCALL 1 6 EXIT 0 7
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 257 4 EXIT 81c27c08 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWEREDW OANR NSIYNSGC:A LSLP L1  N6O TE XLIOTW E0R E7D
 ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 233 4 EXIT 81c27c08 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 1 6 EXIT 0 7
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 233 4 EXIT 81c27c08 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 77 13 EXIT 60139800 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL W1A R6N IENXGI:T  S0P L7 
NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 33s3y s4c aElXlI(T) W 8Aa1RtcN 2I7NcG0:8  S6P
L NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 1 6 EXIT 0 7
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 288 4 EXIT 81c27c08 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
netbsd:syscall+0x208
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED O- -S- YsSysCcAaLlLl  1( n6u mbEerX 4I)T  -0- -

WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 279 4 EXIT 81c27c08 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 1 6 EXIT 0 7
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
4930ba:
WARNING: SPL NOT LOWERED ON SYSCALL 283 4 EXIT 81c27c08 6
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
cpu6: End traceback...
WARNING: SPL NOT LOWERED ON TRAP EXIT 6 0
WARNING: SPL NOT LOWERED ON SYSCALL 1 6 EXIT 0 7

dumping to dev 168,3 (offset=8, size=8373576):
dump Copyright (c) 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2015, 2016
    The NetBSD Foundation, Inc.  All rights reserved.
Copyright (c) 1982, 1986, 1989, 1991, 1993
    The Regents of the University of California.  All rights reserved.

NetBSD 7.99.42 (KVOTHE) #23: Wed Nov  2 09:38:07 CET 2016
	wiz%yt.nih.at@localhost:/disk/6/archive/foreign/src/sys/arch/amd64/compile/obj/KVOTHE

...

netbsd.core.101.gz exists, so I can provide more detail:

(gdb) bt
#0  0xffffffff80119a85 in cpu_reboot (howto=howto@entry=260, bootstr=bootstr@entry=0x0) at /disk/6/archive/foreign/src/sys/arch/amd64/amd64/machdep.c:676
#1  0xffffffff8089072c in vpanic (fmt=0xffffffff80ed31f8 "kernel %sassertion \"%s\" failed: file \"%s\", line %d ", ap=ap@entry=0xfffffe8720904d78)
    at /disk/6/archive/foreign/src/sys/kern/subr_prf.c:342
#2  0xffffffff80bd0b65 in kern_assert (fmt=fmt@entry=0xffffffff80ed31f8 "kernel %sassertion \"%s\" failed: file \"%s\", line %d ")
    at /disk/6/archive/foreign/src/sys/lib/libkern/kern_assert.c:51
#3  0xffffffff8013efa7 in cpu_lwp_free2 (l=l@entry=0xfffffe82c7577360) at /disk/6/archive/foreign/src/sys/arch/x86/x86/vm_machdep.c:262
#4  0xffffffff8084be91 in lwp_free (l=0xfffffe82c7577360, recycle=recycle@entry=false, last=last@entry=false) at /disk/6/archive/foreign/src/sys/kern/kern_lwp.c:1263
#5  0xffffffff8084cc66 in lwp_exit (l=l@entry=0xfffffe824b4a1700) at /disk/6/archive/foreign/src/sys/kern/kern_lwp.c:1093
#6  0xffffffff8084cf39 in lwp_userret (l=l@entry=0xfffffe824b4a1700) at /disk/6/archive/foreign/src/sys/kern/kern_lwp.c:1555
#7  0xffffffff8013e5c9 in mi_userret (l=0xfffffe824b4a1700) at /disk/6/archive/foreign/src/sys/sys/userret.h:94
#8  userret (l=0xfffffe824b4a1700) at ./machine/userret.h:82
#9  syscall (frame=0xfffffe8720904f00) at /disk/6/archive/foreign/src/sys/arch/x86/x86/syscall.c:184
#10 0xffffffff80100761 in Xsyscall ()

Let me know if I should file a PR and what more information you'd like to see.

Thanks,
 Thomas