panic: Negative bio_offset (-15050100712783872) on bio 0xc7725d50

bad block 8239054478774324592, ino 3229486
bad block 7021770428354685254, ino 3229486
panic: Negative bio_offset (-15050100712783872) on bio 0xc7725d50
Debugger("panic")
Stopped at      Debugger+0x54:  xchgl   %ebx,in_Debugger.0
db> trace
Debugger(c043aa25,c04ac1c0,c0435bc2,cd1d1980,100) at Debugger+0x54
panic(c0435bc2,5d2e4000,ffca8803,c7725d50,c0440989) at panic+0xd5
g_dev_strategy(c7725d50,0,c29b42e4,1,c0439d9c) at g_dev_strategy+0xa7
spec_xstrategy(c29c9920,c7725d50,0,c29b42e4,0) at spec_xstrategy+0x3ef
spec_specstrategy(cd1d1a60,cd1d1a84,c02b2982,cd1d1a60,0) at spec_specstrategy+0x72
spec_vnoperate(cd1d1a60,0,ffffe544,4000,0) at spec_vnoperate+0x18
breadn(c29c9920,1ae9720,ffffe544,4000,0) at breadn+0x122
bread(c29c9920,1ae9720,ffffe544,4000,0) at bread+0x4c
ffs_blkfree(c29d4800,c29c9920,6c6c69,6f747561,4000) at ffs_blkfree+0x286
indir_trunc(c4abe200,313a0e0,0,0,c) at indir_trunc+0x334
handle_workitem_freeblocks(c4abe200,0,2,c04af748,c26acc00) at handle_workitem_freeblocks+0x21e
process_worklist_item(0,0,3f65f661,0,c32961e0) at process_worklist_item+0x1fd
softdep_process_worklist(0,0,c044228c,6f4,0) at softdep_process_worklist+0xe0
sched_sync(0,cd1d1d48,c04383a9,312,20) at sched_sync+0x304
fork_exit(c02c4e30,0,cd1d1d48) at fork_exit+0xcf
fork_trampoline() at fork_trampoline+0x1a
--- trap 0x1, eip = 0, esp = 0xcd1d1d7c, ebp = 0 ---
db>

Is this disk corruption, or a bug?

Kris