kern/132331: LOR ufs and syncer

[Matthew West]

>Number:         132331
>Category:       kern
>Synopsis:       LOR ufs and syncer
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Thu Mar 05 12:10:01 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Matthew West
>Release:        FreeBSD 6.2-RELEASE-p4 amd64
>Organization:
>Environment:
System: FreeBSD foo.internal 8.0-CURRENT FreeBSD 8.0-CURRENT #0: Fri Feb 27 12:43:45 GMT 2009 mwest at foo.internal:/usr/obj/usr/src/sys/DEBUGLOCK amd64

>Description:
lock order reversal:
1st 0xffffff0145356a58 ufs (ufs) @ /usr/src/sys/kern/vfs_mount.c:1202
2nd 0xffffff01824d37e8 syncer (syncer) @ /usr/src/sys/kern/vfs_subr.c:2197
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x2a
_witness_debugger() at _witness_debugger+0x2e
witness_checkorder() at witness_checkorder+0x81e
__lockmgr_args() at __lockmgr_args+0xc91
vop_stdlock() at vop_stdlock+0x39
VOP_LOCK1_APV() at VOP_LOCK1_APV+0x9b
_vn_lock() at _vn_lock+0x57
vrele() at vrele+0x151
dounmount() at dounmount+0x2ac
unmount() at unmount+0x24b
syscall() at syscall+0x1e7
Xfast_syscall() at Xfast_syscall+0xab
--- syscall (22, FreeBSD ELF64, unmount), rip = 0x8007c22cc, rsp = 0x7fffffffe8e8, rbp = 0 ---


>How-To-Repeat:
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: