DragonFlyBSD

I was running 4 poudriere jobs on a Xeon-E3 (8 threads) / DragonFly 3.3 system and it panicked after 30 hours

Backtrace:

(kgdb) #0 _get_mycpu () at ./machine/thread.h:69
#1 md_dumpsys (di=<optimized out>)
at /usr/src/sys/platform/pc64/x86_64/dump_machdep.c:265
#2 0xffffffff804f5d12 in dumpsys () at /usr/src/sys/kern/kern_shutdown.c:913
#3 0xffffffff804f6376 in boot (howto=260)
at /usr/src/sys/kern/kern_shutdown.c:373
#4 0xffffffff804f662d in panic (fmt=0xffffffff80906deb "%s")
at /usr/src/sys/kern/kern_shutdown.c:819
#5 0xffffffff808b6408 in trap_fatal (frame=0xffffffe2cb503628,
eva=<optimized out>) at /usr/src/sys/platform/pc64/x86_64/trap.c:1029
#6 0xffffffff808b6f11 in trap (frame=0xffffffe2cb503628)
at /usr/src/sys/platform/pc64/x86_64/trap.c:754
#7 0xffffffff808a0cdf in calltrap ()
at /usr/src/sys/platform/pc64/x86_64/exception.S:188
#8 0xffffffff808b0eb9 in db_read_bytes (addr=7165064483209180471, size=8,
data=0xffffffe2cb503708 "")
at /usr/src/sys/platform/pc64/x86_64/db_interface.c:240
#9 0xffffffff802a735d in db_get_value (addr=7165064483209180471, size=8,
is_signed=0) at /usr/src/sys/ddb/db_access.c:58
#10 0xffffffff808b1b55 in db_nextframe (ip=<optimized out>,
fp=<optimized out>) at /usr/src/sys/platform/pc64/x86_64/db_trace.c:234
#11 db_stack_trace_cmd (addr=<optimized out>, have_addr=<optimized out>,
count=<optimized out>, modif=<optimized out>)
at /usr/src/sys/platform/pc64/x86_64/db_trace.c:440
#12 0xffffffff808b1d17 in print_backtrace (count=-883935480)
at /usr/src/sys/platform/pc64/x86_64/db_trace.c:452
#13 0xffffffff804f65f8 in panic (
fmt=0xffffffff8097713b "unmount: dangling vnode")
at /usr/src/sys/kern/kern_shutdown.c:812
#14 0xffffffff80577a57 in dounmount (mp=0xffffffe27a209700, flags=-883935000)
at /usr/src/sys/kern/vfs_syscalls.c:807
#15 0xffffffff80577c2c in sys_unmount (uap=0xffffffe2cb503a08)
at /usr/src/sys/kern/vfs_syscalls.c:622
#16 0xffffffff808b7683 in syscall2 (frame=0xffffffe2cb503ab8)
at /usr/src/sys/platform/pc64/x86_64/trap.c:1238
#17 0xffffffff808a0f2b in Xfast_syscall ()
at /usr/src/sys/platform/pc64/x86_64/exception.S:323
#18 0x000000000000002b in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)

Core dump and associated files available on leaf:~ftigeot/crash/crash.dangling_vnode