kern/49691: KASSERT(l->l_md.md_gc_ptp == NULL) failed on NetBSD/amd64 7.0_BETA

[KAMADA Ken'ichi <kamada%nanohz.org@localhost>]

>Number:         49691
>Category:       kern
>Synopsis:       KASSERT(l->l_md.md_gc_ptp == NULL) failed on NetBSD/amd64 7.0_BETA
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Feb 24 13:15:00 +0000 2015
>Originator:     KAMADA Ken'ichi
>Release:        NetBSD 7.0_BETA
>Organization:
>Environment:
NetBSD example.org 7.0_BETA NetBSD 7.0_BETA (DIAG) #0: Mon Feb 23 23:16:18 JST 2015  ken%example.org@localhost:/usr/src/sys/arch/amd64/compile/DIAG amd64
Architecture: x86_64
Machine: amd64
kernel: GENERIC + options DIAGNOSTIC

>Description:
I see occasional panics on NetBSD/amd64 7.0_BETA boxes (checked out
on Feb. 23).  Seen on both a real hardware (custom kernconf) and
a VirtualBox guest (GENERIC kernel).
The kernels have the DIAGNOSTIC option enabled.


panic: kernel diagnostic assertion "l->l_md.md_gc_ptp == NULL" failed: file "../../../../arch/x86/x86/vm_machdep.c", line 262
cpu0: Begin traceback...
vpanic() at netbsd:vpanic+0x13c
kern_assert() at netbsd:kern_assert+0x4f
cpu_lwp_free2() at netbsd:cpu_lwp_free2+0x42
lwp_free() at netbsd:lwp_free+0x22f
lwp_wait() at netbsd:lwp_wait+0x7c
exit_lwps() at netbsd:exit_lwps+0xca
exit1() at netbsd:exit1+0x65
sys_exit() at netbsd:sys_exit+0x3a
syscall() at netbsd:syscall+0x9a
--- syscall (number 1) ---
4a0a64:
cpu0: End traceback...

dumping to dev 0,1 (offset=1050072, size=130959):
dump


(gdb) bt
#0  0xffffffff805b2885 in cpu_reboot (howto=howto@entry=260,
    bootstr=bootstr@entry=0x0) at ../../../../arch/amd64/amd64/machdep.c:671
#1  0xffffffff807ae1b4 in vpanic (
    fmt=0xffffffff80bab850 "kernel %sassertion \"%s\" failed: file \"%s\", line %d ", ap=ap@entry=0xfffffe80027f4ca0) at ../../../../kern/subr_prf.c:340
#2  0xffffffff8093f003 in kern_assert (
    fmt=fmt@entry=0xffffffff80bab850 "kernel %sassertion \"%s\" failed: file \"%s\", line %d ") at ../../../../../../lib/libkern/kern_assert.c:51
#3  0xffffffff808dbb34 in cpu_lwp_free2 (l=l@entry=0xfffffe800fc6baa0)
    at ../../../../arch/x86/x86/vm_machdep.c:262
#4  0xffffffff8052d2f8 in lwp_free (l=0xfffffe800fc6baa0,
    recycle=recycle@entry=false, last=last@entry=false)
    at ../../../../kern/kern_lwp.c:1268
#5  0xffffffff8052e423 in lwp_wait (l=l@entry=0xfffffe8010a13640,
    lid=lid@entry=0, departed=departed@entry=0x0, exiting=exiting@entry=true)
    at ../../../../kern/kern_lwp.c:569
#6  0xffffffff8052453e in exit_lwps (l=l@entry=0xfffffe8010a13640)
    at ../../../../kern/kern_exit.c:632
#7  0xffffffff805247a0 in exit1 (l=l@entry=0xfffffe8010a13640, rv=768)
    at ../../../../kern/kern_exit.c:219
#8  0xffffffff80525056 in sys_exit (l=0xfffffe8010a13640,
    uap=0xfffffe80027f4f00, retval=<optimized out>)
    at ../../../../kern/kern_exit.c:181
#9  0xffffffff807c810a in sy_call (rval=0xfffffe80027f4eb8,
    uap=0xfffffe80027f4f00, l=0xfffffe8010a13640,
    sy=0xffffffff80f1a5b0 <sysent+16>) at ../../../../sys/syscallvar.h:61
#10 sy_invoke (code=1, rval=0xfffffe80027f4eb8, uap=0xfffffe80027f4f00,
    l=0xfffffe8010a13640, sy=0xffffffff80f1a5b0 <sysent+16>)
    at ../../../../sys/syscallvar.h:85
#11 syscall (frame=0xfffffe80027f4f00)
    at ../../../../arch/x86/x86/syscall.c:156
#12 0xffffffff80100691 in Xsyscall ()


>How-To-Repeat:
Not known.

>Fix: