FreeBSD lock order reversal (LOR) #280

lock order reversal:
 1st 0xc2ae79c4 ufs (ufs) @ sys/kern/vfs_mount.c:1190
 2nd 0xc2ae7df4 devfs (devfs) @ sys/kern/vfs_subr.c:2079
		
KDB: stack backtrace:
db_trace_self_wrapper(c0be7dc5,c267d9c4,c0874305,4,c0be3343,...) at db_trace_self_wrapper+0x26
kdb_backtrace(4,c0be3343,c290c180,c290c0b0,c267da20,...) at kdb_backtrace+0x29
_witness_debugger(c0beaaaf,c2ae7df4,c0bda8f2,c290c0b0,c0bf178c,...) at _witness_debugger+0x25
witness_checkorder(c2ae7df4,9,c0bf178c,81f,0,...) at witness_checkorder+0x839
__lockmgr_args(c2ae7df4,80100,c2ae7e10,0,0,...) at __lockmgr_args+0x797
vop_stdlock(c267db28,c08740ab,c0bdab23,80100,c2ae7d9c,...) at vop_stdlock+0x62
VOP_LOCK1_APV(c0cc62c0,c267db28,c294fe24,c0d02600,c2ae7d9c,...) at VOP_LOCK1_APV+0xa5
_vn_lock(c2ae7d9c,80100,c0bf178c,81f,8,...) at _vn_lock+0x5e
vget(c2ae7d9c,80100,c294fd80,160,c0bdaa45,...) at vget+0xc9
devfs_allocv(c2b63180,c2b79000,c267dbc0,c294fd80,c2ae796c,...) at devfs_allocv+0x11a
devfs_root(c2b79000,80000,c267dbfc,c294fd80,0,...) at devfs_root+0x51
dounmount(c2b79000,80000,c294fd80,c24b1230,0,...) at dounmount+0x3f6
vfs_unmountall(c0be48c6,0,c0be4970,12a,0,...) at vfs_unmountall+0x4e
boot(c0d36c50,0,c0be4970,ad,c267dd2c,...) at boot+0x44f
reboot(c294fd80,c267dcf8,4,c0bebc92,c0cc9cc8,...) at reboot+0x4b
syscall(c267dd38) at syscall+0x2a3
Xint0x80_syscall() at Xint0x80_syscall+0x20
--- syscall (55, FreeBSD ELF32, reboot), eip = 0x8050ff3, esp = 0xbfbfe8cc, ebp = 0xbfbfe9a8 ---
		

• freebsd-current (thread)