Page fault at ffs_softdep.c:3391

With GENERIC HEAD from May 14 19:16 UTC I got:

lock order reversal
 1st 0xc0961fe0 Softdep Lock (Softdep Lock) _at_ ufs/ffs/ffs_softdep.c:3390
 2nd 0xc09053c4 user map (user map) _at_ vm/vm_map.c:2997
KDB: stack backtrace:
kdb_backtrace(0,ffffffff,c09179a0,c0917e00,...) at kdb_backtrace+0x29
witness_checkorder(c09053c4,9,c085a8da,bb5) at witness_checkorder+0x55c
_sx_xlock(c09053c4,c085a8d1,bb5) at _sx_xlock+0x50
_vm_map_lock_read(c0905380,c085a8d1,...) at _vm_map_lock_read+0x37
vm_map_lookup(cea73b5c,0,1,cea73b60,cea73b50) at vm_map_lookup+0x28
vm_fault(c0905380,0,1,0,c1751a80) at vm_fault+0x66
trap_pfault(cea73c24,0,20) at trap_pfault+0xf2
trap(cea70008,c0640028,c0950028,c1751a80,c219ea60) at trap+0x33d
calltrap() at calltrap+0x5
--- trap 0xc, eip = 0xc0755fd9, esp = 0xcea73c64, ebp = 0xcea73c94 ---
handle_workitem_remove(c219ea60,0) at handle_workitem_remove+0x6d
process_worklist_item(0,0) at process_worklist_item+0x18d
softdep_process_worklist(0) at softdep_process_worklist+0xf4
sched_sync(0,cea73d38,0,c06729a8,0) at sched_sync+0x25e
fork_exit(c06729a8,0,cea73d38) at fork_exit+0xa0
fork_trampoline() at fork_trampoline+0x8
--- trap 0x1, eip = 0, esp = 0xcea73d6c, ebp = 0 ---


Fatal trap 12: page fault while in kernel mode
cpuid = 0; apic id = 00
fault virtual address   = 0x20
fault code              = supervisor read, page not present
instruction pointer     = 0x20:0xc0755fd9
stack pointer           = 0x28:0xcea73c64
frame pointer           = 0x28:0xcea73c94
code segment            = base 0x0, limit 0xfffff, type 0x1b
                        = DPL 0, pres 1, def32 1, gran 1
processor eflags        = interrupt enabled, resume, IOPL = 0
current process         = 56 (syncer)

More info at http://www.holm.cc/stress/log/cons131.html
-- 
Peter Holm