DragonFlyBSD

panic during buildworld using NFS /usr/{src,obj}.

Using master from 22/11-13.

System was paging heavily
(hw.physmem was reduced to get smaller dump, for other panic; too high -jN was used)

Crash dump on leaf: ~thomas/crash/bog.x86_64/9.
-
ad0: TIMEOUT - WRITE_DMA48 retrying (1 retry left) LBA=269696568
ad0: FAILURE - WRITE_DMA48 status=51<READY,DSC,ERROR> error=10<NID_NOT_FOUND> LBA=269696568
swap_pager: I/O error - pageout failed; offset 2505633792,size 4096, error 5
panic: assertion "LWKT_TOKEN_HELD_ANY(vm_object_token(object))" failed in swp_pager_lookup at /usr/src/sys/vm/swap_pager.c:2098
..
(kgdb) bt
..
#13 0xffffffff804197b3 in swp_pager_lookup (index=3078,
object=0xffffffe05c011d20) at /usr/src/sys/vm/swap_pager.c:2098
#14 swp_pager_meta_ctl (object=0xffffffe05c011d20, index=3078,
flags=flags@entry=2) at /usr/src/sys/vm/swap_pager.c:2383
#15 0xffffffff80419eb2 in swp_pager_async_iodone (bio=0xffffffe0034901b0)
at /usr/src/sys/vm/swap_pager.c:1810
#16 0xffffffff80334c50 in biodone (bio=0xffffffe0034901b0,
bio@entry=0xffffffe0034902c0) at /usr/src/sys/kern/vfs_bio.c:3907
#17 0xffffffff80280673 in ad_done (request=0xffffffe03156f500)
at /usr/src/sys/dev/disk/nata/ata-disk.c:370
#18 0xffffffff80285cb0 in ata_completed (context=0xffffffe03156f500,
dummy=<optimized out>) at /usr/src/sys/dev/disk/nata/ata-queue.c:516
#19 0xffffffff803089bc in taskqueue_run (queue=0xffffffe00d5fb8c8,
lock_held=lock_held@entry=0) at /usr/src/sys/kern/subr_taskqueue.c:332
#20 0xffffffff80308a52 in taskqueue_swi_mp_run (arg=<optimized out>,
frame=<optimized out>) at /usr/src/sys/kern/subr_taskqueue.c:423
#21 0xffffffff802a66f9 in ithread_handler (arg=<optimized out>)
at /usr/src/sys/kern/kern_intr.c:844
#22 0xffffffff802e2ff7 in lwkt_deschedule_self (td=<optimized out>)
at /usr/src/sys/kern/lwkt_thread.c:327
..