FreeBSD lock order reversal (LOR) #276

lock order reversal:
 1st 0xc1e60164 ufs (ufs) @ sys/kern/vfs_mount.c:1190
 2nd 0xc1e97270 devfs (devfs) @ sys/ufs/ffs/ffs_vfsops.c:1174
		
KDB: stack backtrace:
db_trace_self_wrapper(c0839d29,cac339a8,c05e1e05,4,c0835575,...) at db_trace_self_wrapper+0x26
kdb_backtrace(4,c0835575,c1c2ddd8,c1c2dd08,cac33a04,...) at kdb_backtrace+0x29
_witness_debugger(c083c844,c1e97270,c082cb0b,c1c2dd08,c08550ff,...) at _witness_debugger+0x25
witness_checkorder(c1e97270,9,c08550ff,496,c1e9728c,...) at witness_checkorder+0x839
__lockmgr_args(c1e97270,80400,c1e9728c,0,0,...) at __lockmgr_args+0x797
vop_stdlock(cac33b0c,542,cac33b04,80400,c1e97218,...) at vop_stdlock+0x62
VOP_LOCK1_APV(c0884680,cac33b0c,c20af860,c08b99e0,c1e97218,...) at VOP_LOCK1_APV+0xa5
_vn_lock(c1e97218,80400,c08550ff,496,c1e87200,...) at _vn_lock+0x5e
ffs_flushfiles(c1e4a500,2,c20bad80,542,3,...) at ffs_flushfiles+0xa7
softdep_flushfiles(c1e4a500,2,c20bad80,8a0,c05749d4,...) at softdep_flushfiles+0x2e
ffs_unmount(c1e4a500,80000,c20bad80,c20bad80,0,...) at ffs_unmount+0x14c
dounmount(c1e4a500,80000,c20bad80,c1993a30,0,...) at dounmount+0x482
vfs_unmountall(c0836af6,0,c0836ba0,12a,0,...) at vfs_unmountall+0x4e
boot(c08d3810,0,c0836ba0,ad,cac33d2c,...) at boot+0x3cf
reboot(c20bad80,cac33cf8,4,c083ddff,c0887fa8,...) at reboot+0x4b
syscall(cac33d38) at syscall+0x2a3
Xint0x80_syscall() at Xint0x80_syscall+0x20
--- syscall (55, FreeBSD ELF32, reboot), eip = 0x280be80b, esp = 0xbfbfecfc, ebp = 0xbfbfed38 ---
		

• (thread)