Excerpt from /var/crash/core.txt.0 generated after a kernel panic upon restarting wireguard on a FreeBSD 12.0 host.

core.txt.0

 dumped core - see /var/crash/vmcore.0

Tue Jan 29 11:09:03 UTC 2019

FreeBSD  12.0-RELEASE-p2 FreeBSD 12.0-RELEASE-p2 GENERIC  amd64

panic: page fault

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Unread portion of the kernel message buffer:
<6>in_scrubprefix: err=65, prefix delete failed
<6>wg0: deletion failed: 3


Fatal trap 12: page fault while in kernel mode
cpuid = 1; apic id = 01
fault virtual address	= 0x0
fault code		= supervisor read data, page not present
instruction pointer	= 0x20:0xffffffff80cc3fe3
stack pointer	        = 0x28:0xfffffe001de86300
frame pointer	        = 0x28:0xfffffe001de86450
code segment		= base 0x0, limit 0xfffff, type 0x1b
			= DPL 0, pres 1, long 1, def32 0, gran 1
processor eflags	= interrupt enabled, resume, IOPL = 0
current process		= 3813 (wireguard-go)
trap number		= 12
panic: page fault
cpuid = 1
time = 1548760075
KDB: stack backtrace:
#0 0xffffffff80be7977 at kdb_backtrace+0x67
#1 0xffffffff80b9b563 at vpanic+0x1a3
#2 0xffffffff80b9b3b3 at panic+0x43
#3 0xffffffff8107496f at trap_fatal+0x35f
#4 0xffffffff810749c9 at trap_pfault+0x49
#5 0xffffffff81073fee at trap+0x29e
#6 0xffffffff8104f315 at calltrap+0x8
#7 0xffffffff80de0f73 at in6_purgeaddr+0x463
#8 0xffffffff80c9662f at if_purgeaddrs+0x21f
#9 0xffffffff80ca79c1 at tunclose+0x1f1
#10 0xffffffff80a518ca at devfs_close+0x3ba
#11 0xffffffff811f89b8 at VOP_CLOSE_APV+0x78
#12 0xffffffff80c7b6bf at vn_close1+0xdf
#13 0xffffffff80c7a3c0 at vn_closefile+0x50
#14 0xffffffff80a5224c at devfs_close_f+0x2c
#15 0xffffffff80b4363a at _fdrop+0x1a
#16 0xffffffff80b466e4 at closef+0x244
#17 0xffffffff80b43b69 at closefp+0x99
Uptime: 5m14s
Dumping 190 out of 2005 MB:..9%..17%..26%..34%..43%..51%..68%..76%..85%..93%

Reading symbols from /boot/kernel/zfs.ko...Reading symbols from /usr/lib/debug//boot/kernel/zfs.ko.debug...done.
done.
Loaded symbols for /boot/kernel/zfs.ko
Reading symbols from /boot/kernel/opensolaris.ko...Reading symbols from /usr/lib/debug//boot/kernel/opensolaris.ko.debug...done.
done.
Loaded symbols for /boot/kernel/opensolaris.ko
Reading symbols from /boot/modules/vboxguest.ko...done.
Loaded symbols for /boot/modules/vboxguest.ko
Reading symbols from /boot/kernel/intpm.ko...Reading symbols from /usr/lib/debug//boot/kernel/intpm.ko.debug...done.
done.
Loaded symbols for /boot/kernel/intpm.ko
Reading symbols from /boot/kernel/smbus.ko...Reading symbols from /usr/lib/debug//boot/kernel/smbus.ko.debug...done.
done.
Loaded symbols for /boot/kernel/smbus.ko
#0  doadump (textdump=<value optimized out>) at pcpu.h:230
230	pcpu.h: No such file or directory.
	in pcpu.h
(kgdb) #0  doadump (textdump=<value optimized out>) at pcpu.h:230
#1  0xffffffff80b9b14b in kern_reboot (howto=260)
    at /usr/src/sys/kern/kern_shutdown.c:446
#2  0xffffffff80b9b5c3 in vpanic (fmt=<value optimized out>, 
    ap=<value optimized out>) at /usr/src/sys/kern/kern_shutdown.c:872
#3  0xffffffff80b9b3b3 in panic (fmt=<value optimized out>)
    at /usr/src/sys/kern/kern_shutdown.c:799
#4  0xffffffff8107496f in trap_fatal (frame=0xfffffe001de86240, eva=0)
    at /usr/src/sys/amd64/amd64/trap.c:929
#5  0xffffffff810749c9 in trap_pfault (frame=0xfffffe001de86240, usermode=0)
    at pcpu.h:230
#6  0xffffffff81073fee in trap (frame=0xfffffe001de86240)
    at /usr/src/sys/amd64/amd64/trap.c:441
#7  0xffffffff8104f315 in calltrap ()
    at /usr/src/sys/amd64/amd64/exception.S:232
#8  0xffffffff80cc3fe3 in rtsock_addrmsg (cmd=2, ifa=0xfffff80062f71200, 
    fibnum=-1) at /usr/src/sys/net/rtsock.c:1337
#9  0xffffffff80de0f73 in in6_purgeaddr (ifa=0xfffff80062f71200)
    at /usr/src/sys/netinet6/in6.c:193
#10 0xffffffff80c9662f in if_purgeaddrs (ifp=0xfffff80062845000)
    at /usr/src/sys/net/if.c:995
#11 0xffffffff80ca79c1 in tunclose (dev=<value optimized out>, 
    foo=<value optimized out>, bar=<value optimized out>, 
    td=<value optimized out>) at /usr/src/sys/net/if_tun.c:478
#12 0xffffffff80a518ca in devfs_close (ap=<value optimized out>)
    at /usr/src/sys/fs/devfs/devfs_vnops.c:650
#13 0xffffffff811f89b8 in VOP_CLOSE_APV (vop=<value optimized out>, 
    a=0xfffffe001de86788) at vnode_if.c:534
#14 0xffffffff80c7b6bf in vn_close1 (vp=0xfffff8006291ad20, flags=7, 
    file_cred=0xfffff80062849a00, td=0xfffff8001da8d000, keep_ref=false)
    at vnode_if.h:225
#15 0xffffffff80c7a3c0 in vn_closefile (fp=0xfffff8006a031050, 
    td=<value optimized out>) at /usr/src/sys/kern/vfs_vnops.c:1563
#16 0xffffffff80a5224c in devfs_close_f (fp=0xfffff8006a031050, 
    td=<value optimized out>) at /usr/src/sys/fs/devfs/devfs_vnops.c:669
#17 0xffffffff80b4363a in _fdrop (fp=0xfffff8006a031050, 
    td=<value optimized out>) at file.h:353
#18 0xffffffff80b466e4 in closef (fp=0xfffff8006a031050, td=0xfffff8001da8d000)
    at /usr/src/sys/kern/kern_descrip.c:2528
#19 0xffffffff80b43b69 in closefp (fdp=0xfffff8006a04d450, 
    fd=<value optimized out>, fp=0xfffff8006a031050, td=0xfffff8001da8d000, 
    holdleaders=0) at /usr/src/sys/kern/kern_descrip.c:1199
#20 0xffffffff81075449 in amd64_syscall (td=0xfffff8001da8d000, traced=0)
    at subr_syscall.c:135
#21 0xffffffff8104fbfd in fast_syscall_common ()
    at /usr/src/sys/amd64/amd64/exception.S:504
#22 0x000000000048bdb0 in ?? ()
Previous frame inner to this frame (corrupt stack?)
Current language:  auto; currently minimal
(kgdb)