Re: Seeing lock order reversal

See archives / UPDATING for an explanation.



On 3/18/08, Robert Huff <roberthuff_at_rcn.com> wrote:
>
> Alex Goncharov writes:
>
> >  I am trying to source-upgrade one of my 7.0 systems to 8.0-CURRENT.
>
> 	I updated on Friday.
>
>
> >  The very first 8.0 build (this morning) gave me the kernel that didn't
> >  boot.  Built it again, finishing about 15 minutes ago.  This one
> >  booted all right but I see this in `/var/log/messages':
> >
> >
> ================================================================================
> >  WARNING: WITNESS option enabled, expect reduced performance.
> >  lock order reversal:
> >  1st 0xc4093e28 devfs (devfs) _at_
> /mnt/wdx/freebsd/8.0/usr/src/sys/kern/vfs_subr.c:2064
> >  2nd 0xc4172b54 devfsmount (devfsmount) _at_
> /mnt/wdx/freebsd/8.0/usr/src/sys/fs/devfs/devfs_vnops.c:201
> >  KDB: stack backtrace:
> >  db_trace_self_wrapper(c0af5d71,e2888bbc,c07a70de,c0af8353,c4172b54,...)
> at db_trace_self_wrapper+0x26
> >  kdb_backtrace(c0af8353,c4172b54,c0ae90df,c0ae90df,c0ae9120,...) at
> kdb_backtrace+0x29
> >  witness_checkorder(c4172b54,9,c0ae9120,c9,c7,...) at
> witness_checkorder+0x6de
> >  _sx_xlock(c4172b54,0,c0ae9120,c9,c4172b54,...) at _sx_xlock+0x7d
> >  devfs_allocv(c415db80,c4174000,e2888c28,c3e1ecc0,c0afe288,...) at
> devfs_allocv+0x144
> >  devfs_root(c4174000,2,c0c67378,c3e1ecc0,ca,...) at devfs_root+0x51
> >  set_rootvnode(c0c67360,0,c0afe288,5f4,c07e4aa0,...) at set_rootvnode+0x2b
> >  vfs_mountroot(c0c15270,4,c0aed8e7,264,0,...) at vfs_mountroot+0x356
> >  start_init(0,e2888d38,c0aef370,30c,c3e1ccd0,...) at start_init+0x65
> >  fork_exit(c0737740,0,e2888d38) at fork_exit+0xb8
> >  fork_trampoline() at fork_trampoline+0x8
> >  --- trap 0, eip = 0, esp = 0xe2888d70, ebp = 0 ---
> >  Trying to mount root from ufs:/dev/ad4s1a
> >  lock order reversal:
> >  1st 0xc40939e8 ufs (ufs) _at_
> /mnt/wdx/freebsd/8.0/usr/src/sys/kern/vfs_subr.c:2064
> >  2nd 0xc4174000 vfslock (vfslock) _at_
> /mnt/wdx/freebsd/8.0/usr/src/sys/kern/vfs_subr.c:364
> >  KDB: stack backtrace:
> >  db_trace_self_wrapper(c0af5d71,e28889d8,c07a70de,c0af8353,c4174000,...)
> at db_trace_self_wrapper+0x26
> >  kdb_backtrace(c0af8353,c4174000,c0afe39a,c0afe39a,c0afe937,...) at
> kdb_backtrace+0x29
> >  witness_checkorder(c4174000,1,c0afe937,16c,e2888a18,...) at
> witness_checkorder+0x6de
> >  _lockmgr_args(c4174000,20001,c4174030,0,ffffffff,...) at
> _lockmgr_args+0x1d5
> >  vfs_busy(c4174000,0,0,c3e1ecc0,e2888b58,...) at vfs_busy+0x1b0
> >  lookup(e2888b44,c0afe022,c6,bf,c3dee22c,...) at lookup+0x7bf
> >  namei(e2888b44,c4174030,1c1,c0afe288,e2888b54,...) at namei+0x34b
> >  kern_unlink(c3e1ecc0,c0afe6d9,1,62f,0,...) at kern_unlink+0x40
> >  vfs_mountroot_try(c0afe893,c0aec557,c0ae4ade,1,c07e4aa0,...) at
> vfs_mountroot_try+0x470
> >  vfs_mountroot(c0c15270,4,c0aed8e7,264,0,...) at vfs_mountroot+0x418
> >  start_init(0,e2888d38,c0aef370,30c,c3e1ccd0,...) at start_init+0x65
> >  fork_exit(c0737740,0,e2888d38) at fork_exit+0xb8
> >  fork_trampoline() at fork_trampoline+0x8
> >  --- trap 0, eip = 0, esp = 0xe2888d70, ebp = 0 ---
> >  lock order reversal:
> >  1st 0xc3e22044 user map (user map) _at_
> /mnt/wdx/freebsd/8.0/usr/src/sys/vm/vm_map.c:3111
> >  2nd 0xc40937c8 ufs (ufs) _at_
> /mnt/wdx/freebsd/8.0/usr/src/sys/kern/vfs_subr.c:2064
> >  KDB: stack backtrace:
> >  db_trace_self_wrapper(c0af5d71,e28889c4,c07a70de,c0af8353,c40937c8,...)
> at db_trace_self_wrapper+0x26
> >  kdb_backtrace(c0af8353,c40937c8,c0aece96,c0aece96,c0afe937,...) at
> kdb_backtrace+0x29
> >  witness_checkorder(c40937c8,1,c0afe937,810,e28889e8,...) at
> witness_checkorder+0x6de
> >  _lockmgr_args(c40937c8,30041,c40937f8,0,ffffffff,...) at
> _lockmgr_args+0x1d5
> >  ffs_lock(e2888a78,c075fc3d,c0c20554,30041,c4093770,...) at ffs_lock+0xa3
> >  VOP_LOCK1_APV(c0bcbec0,e2888a78,c0aec555,3,c40937f8,...) at
> VOP_LOCK1_APV+0xa5
> >  _vn_lock(c4093770,30041,c0afe937,810,0,...) at _vn_lock+0xf7
> >  vget(c4093770,30041,c3e1ecc0,4a9,c1460600,...) at vget+0x10b
> >  vnode_pager_lock(c1460480,0,c0b157d5,127,e2888be8,...) at
> vnode_pager_lock+0x1ad
> >  vm_fault(c3e22000,80cf000,2,8,80cf340,...) at vm_fault+0x1df
> >  trap_pfault(5,0,c0b23bd2,2c4,c3e1ccd0,...) at trap_pfault+0x118
> >  trap(e2888d38) at trap+0x259
> >  calltrap() at calltrap+0x6
> >  --- trap 0xc, eip = 0x80480e5, esp = 0xbfbfeef0, ebp = 0xbfbfef10 ---
>
> 	I'm gettig both of these as well.  It doesn't stop the system
> from booting, or _seem_ to affect operation ... but it would be nice
> if they would go away.
>
>
>
> 				Robert Huff
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