LORs

[Dmitry Sivachenko]

Hello!

I have a FreeBSD-10/stable box (r276908) with UFS partitions:

tunefs: POSIX.1e ACLs: (-a)                                disabled
tunefs: NFSv4 ACLs: (-N)                                   disabled
tunefs: MAC multilabel: (-l)                               disabled
tunefs: soft updates: (-n)                                 enabled
tunefs: soft update journaling: (-j)                       disabled
tunefs: gjournal: (-J)                                     disabled
tunefs: trim: (-t)                                         disabled


I am observing the following LORs:

lock order reversal:
 1st 0xfffffe0baf12f1c0 bufwait (bufwait) @ /opt/WRK/src/sys/kern/vfs_bio.c:3065
 2nd 0xfffff800112db800 dirhash (dirhash) @ /opt/WRK/src/sys/ufs/ufs/ufs_dirhash
.c:284
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0c57fd5380
kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe0c57fd5430
witness_checkorder() at witness_checkorder+0xc04/frame 0xfffffe0c57fd54b0
_sx_xlock() at _sx_xlock+0x47/frame 0xfffffe0c57fd54f0
ufsdirhash_add() at ufsdirhash_add+0x3a/frame 0xfffffe0c57fd5530
ufs_direnter() at ufs_direnter+0x6a0/frame 0xfffffe0c57fd55f0
ufs_makeinode() at ufs_makeinode+0x46e/frame 0xfffffe0c57fd57b0
ufs_create() at ufs_create+0x2d/frame 0xfffffe0c57fd57d0
VOP_CREATE_APV() at VOP_CREATE_APV+0xa1/frame 0xfffffe0c57fd5800
vn_open_cred() at vn_open_cred+0x359/frame 0xfffffe0c57fd5960
kern_openat() at kern_openat+0x23a/frame 0xfffffe0c57fd5ae0
amd64_syscall() at amd64_syscall+0x244/frame 0xfffffe0c57fd5bf0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0c57fd5bf0
--- syscall (5, FreeBSD ELF64, sys_open), rip = 0x80095c5ba, rsp = 0x7fffffffe8b8, rbp = 0x7fffffffea50 ---



lock order reversal:
 1st 0xfffff801245929a0 ufs (ufs) @ /opt/WRK/src/sys/kern/vfs_subr.c:2157
 2nd 0xfffffe0baf13f138 bufwait (bufwait) @ /opt/WRK/src/sys/ufs/ffs/ffs_vnops.c:262
 3rd 0xfffff80124595240 ufs (ufs) @ /opt/WRK/src/sys/kern/vfs_subr.c:2157
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0c580861e0
kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe0c58086290
witness_checkorder() at witness_checkorder+0xc04/frame 0xfffffe0c58086310
__lockmgr_args() at __lockmgr_args+0x738/frame 0xfffffe0c58086440
ffs_lock() at ffs_lock+0x84/frame 0xfffffe0c58086490
VOP_LOCK1_APV() at VOP_LOCK1_APV+0xab/frame 0xfffffe0c580864c0
_vn_lock() at _vn_lock+0x43/frame 0xfffffe0c58086520
vget() at vget+0x5b/frame 0xfffffe0c58086560
vfs_hash_get() at vfs_hash_get+0xe1/frame 0xfffffe0c580865b0
ffs_vgetf() at ffs_vgetf+0x40/frame 0xfffffe0c58086640
softdep_sync_buf() at softdep_sync_buf+0x919/frame 0xfffffe0c58086720
ffs_syncvnode() at ffs_syncvnode+0x226/frame 0xfffffe0c580867a0
ffs_sync() at ffs_sync+0x20f/frame 0xfffffe0c58086860
vfs_write_suspend() at vfs_write_suspend+0x17a/frame 0xfffffe0c580868a0
vfs_write_suspend_umnt() at vfs_write_suspend_umnt+0x1c/frame 0xfffffe0c580868d0
ffs_unmount() at ffs_unmount+0x58/frame 0xfffffe0c58086930
dounmount() at dounmount+0x409/frame 0xfffffe0c580869b0
sys_unmount() at sys_unmount+0x2bc/frame 0xfffffe0c58086ae0
amd64_syscall() at amd64_syscall+0x244/frame 0xfffffe0c58086bf0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0c58086bf0
--- syscall (22, FreeBSD ELF64, sys_unmount), rip = 0x80088f64a, rsp = 0x7fffffffe198, rbp = 0x7fffffffe2b0 ---


lock order reversal:
 1st 0xfffff8001338fd50 ufs (ufs) @ /opt/WRK/src/sys/kern/vfs_mount.c:1223
 2nd 0xfffff8001334e418 devfs (devfs) @ /opt/WRK/src/sys/ufs/ffs/ffs_vfsops.c:1375
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2b/frame 0xfffffe0c58086500
kdb_backtrace() at kdb_backtrace+0x39/frame 0xfffffe0c580865b0
witness_checkorder() at witness_checkorder+0xc04/frame 0xfffffe0c58086630
__lockmgr_args() at __lockmgr_args+0x738/frame 0xfffffe0c58086760
vop_stdlock() at vop_stdlock+0x3c/frame 0xfffffe0c58086780
VOP_LOCK1_APV() at VOP_LOCK1_APV+0xab/frame 0xfffffe0c580867b0
_vn_lock() at _vn_lock+0x43/frame 0xfffffe0c58086810
ffs_flushfiles() at ffs_flushfiles+0x88/frame 0xfffffe0c58086870
softdep_flushfiles() at softdep_flushfiles+0x62/frame 0xfffffe0c580868d0
ffs_unmount() at ffs_unmount+0x89/frame 0xfffffe0c58086930
dounmount() at dounmount+0x409/frame 0xfffffe0c580869b0
sys_unmount() at sys_unmount+0x2bc/frame 0xfffffe0c58086ae0
amd64_syscall() at amd64_syscall+0x244/frame 0xfffffe0c58086bf0
Xfast_syscall() at Xfast_syscall+0xfb/frame 0xfffffe0c58086bf0
--- syscall (22, FreeBSD ELF64, sys_unmount), rip = 0x80088f64a, rsp = 0x7fffffffe198, rbp = 0x7fffffffe2b0 ---


Does it make any interest or is it harmless?

Thanks!