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Date:      Sat, 8 May 2010 13:19:40 -1000 (HST)
From:      Jeff Roberson <jroberson@jroberson.net>
To:        =?ISO-8859-15?Q?Ulrich_Sp=F6rlein?= <uqs@spoerlein.net>
Cc:        Attilio Rao <attilio@freebsd.org>, current@freebsd.org
Subject:   Re: LOR: ufs vs bufwait
Message-ID:  <alpine.BSF.2.00.1005081317190.1398@desktop>
In-Reply-To: <20100508174838.GJ88504@acme.spoerlein.net>
References:  <20100508102005.GB1867@elmar.spoerlein.net> <20100508155127.GC1867@elmar.spoerlein.net> <q2x3bbf2fe11005080900leb42b4efoaadd3e6e5b2d60f2@mail.gmail.com> <20100508174838.GJ88504@acme.spoerlein.net>

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On Sat, 8 May 2010, Ulrich Sp?rlein wrote:

> On Sat, 08.05.2010 at 18:00:50 +0200, Attilio Rao wrote:
>> 2010/5/8 Ulrich Sp?rlein <uqs@spoerlein.net>:
>>> On Sat, 08.05.2010 at 12:20:05 +0200, Ulrich Sp?rlein wrote:
>>>> This LOR also is not yet listed on the LOR page, so I guess it's rather
>>>> new. I do use SUJ.
>>>>
>>>> lock order reversal:
>>>>  1st 0xc48388d8 ufs (ufs) @ /usr/src/sys/kern/vfs_lookup.c:502
>>>>  2nd 0xec0fe304 bufwait (bufwait) @ /usr/src/sys/ufs/ffs/ffs_softdep.c:11363
>>>>  3rd 0xc49e56b8 ufs (ufs) @ /usr/src/sys/kern/vfs_subr.c:2091
>>>> KDB: stack backtrace:
>>>> db_trace_self_wrapper(c09394fe,fb817308,c062e515,c061e8ab,c093c4f1,...) at db_trace_self_wrapper+0x26
>>>> kdb_backtrace(c061e8ab,c093c4f1,c418b168,c418ef28,fb817364,...) at kdb_backtrace+0x29
>>>> _witness_debugger(c093c4f1,c49e56b8,c092e785,c418ef28,c094369d,...) at _witness_debugger+0x25
>>>> witness_checkorder(c49e56b8,9,c094369d,82b,0,...) at witness_checkorder+0x839
>>>> __lockmgr_args(c49e56b8,80100,c49e56d8,0,0,...) at __lockmgr_args+0x7f9
>>>> ffs_lock(fb817488,c062e2bb,c0942b3f,80100,c49e5660,...) at ffs_lock+0x82
>>>> VOP_LOCK1_APV(c09bd600,fb817488,c4827cd4,c09d62a0,c49e5660,...) at VOP_LOCK1_APV+0xb5
>>>> _vn_lock(c49e5660,80100,c094369d,82b,4,...) at _vn_lock+0x5e
>>>> vget(c49e5660,80100,c4827c30,50,0,...) at vget+0xb9
>>>> vfs_hash_get(c47bea20,b803,80000,c4827c30,fb8175d8,...) at vfs_hash_get+0xe6
>>>> ffs_vgetf(c47bea20,b803,80000,fb8175d8,1,...) at ffs_vgetf+0x49
>>>> softdep_sync_metadata(c4838880,0,c0962957,144,0,...) at softdep_sync_metadata+0xc82
>>>> ffs_syncvnode(c4838880,1,c4827c30,fb817698,246,...) at ffs_syncvnode+0x3e2
>>>> ffs_truncate(c4838880,200,0,880,c41fb480,...) at ffs_truncate+0x862
>>>> ufs_direnter(c4838880,c49e5660,fb81794c,fb817bd4,0,...) at ufs_direnter+0x8d4
>>>> ufs_makeinode(fb817bd4,0,fb817b30,fb817a94,c08e4cf5,...) at ufs_makeinode+0x517
>>>> ufs_create(fb817b30,fb817b48,0,0,fb817ba8,...) at ufs_create+0x30
>>>> VOP_CREATE_APV(c09bd600,fb817b30,2,fb817ac0,0,...) at VOP_CREATE_APV+0xa5
>>>> vn_open_cred(fb817ba8,fb817c5c,1a4,0,c41fb480,...) at vn_open_cred+0x1de
>>>> vn_open(fb817ba8,fb817c5c,1a4,c47e2428,0,...) at vn_open+0x3b
>>>> kern_openat(c4827c30,ffffff9c,804c5e8,0,602,...) at kern_openat+0x125
>>>> kern_open(c4827c30,804c5e8,0,601,21b6,...) at kern_open+0x35
>>>> open(c4827c30,fb817cf8,c0972725,c091f062,c47ea2a8,...) at open+0x30
>>>> syscall(fb817d38) at syscall+0x220
>>>> Xint0x80_syscall() at Xint0x80_syscall+0x20
>>>> --- syscall (5, FreeBSD ELF32, open), eip = 0x2817bf33, esp = 0xbfbfec4c, ebp = 0xbfbfecb8 ---
>>>
>>> And now the system is hanging again. While I can still ping and receive
>>> dmesg updates (eg. USB ports appearing), I/O is frozen solid. This is
>>> during portupgrade, when the configure script runs and usually takes 1-2
>>> minutes to provoke.
>>>
>>> This part looks supsicious to me:
>>>
>>> db> show alllocks
>>> Process 28014 (mkdir) thread 0xc691ac30 (100152)
>>> exclusive lockmgr bufwait (bufwait) r = 0 (0xec2bdaf0) locked @ /usr/src/sys/ufs/ffs/ffs_softdep.c:10684
>>> exclusive lockmgr ufs (ufs) r = 0 (0xc6bcd5a8) locked @ /usr/src/sys/kern/vfs_subr.c:2091
>>> exclusive lockmgr bufwait (bufwait) r = 0 (0xec2983f4) locked @ /usr/src/sys/ufs/ffs/ffs_softdep.c:11363
>>> exclusive lockmgr ufs (ufs) r = 0 (0xc6d976b8) locked @ /usr/src/sys/kern/vfs_lookup.c:502
>>> Process 1990 (sshd) thread 0xc5462750 (100117)
>>> exclusive sx so_rcv_sx (so_rcv_sx) r = 0 (0xc546e08c) locked @ /usr/src/sys/kern/uipc_sockbuf.c:148
>>> Process 12 (intr) thread 0xc41f4750 (100004)
>>> exclusive sleep mutex ttymtx (ttymtx) r = 0 (0xc425ae04) locked @ /usr/src/sys/dev/dcons/dcons_os.c:232
>>> db>
>>
>> Along with show alllocks may you also get the following from DDB:
>> ps, show pcpu, alltrace, lockedvnods.
>
> 1. a kernel before SUJ went in is running fine with SU only
> 2. the following is on a recent -CURRENT that has SUJ, *but* i've
> disabled it, so it is running with soft-updates only (I hope)
>
> I ran a portupgrade and the first configure script triggered the I/O
> hang
>
> db> ps
>  pid  ppid  pgrp   uid   state   wmesg     wchan    cmd
> 13467 13444 12937     0  R+                          mkdir
> 13444 13204 12937     0  S+      wait     0xc54352a8 sh
> 13204 13035 12937     0  S+      wait     0xc5436000 sh
> 13035 12937 12937     0  S+      wait     0xc4ffad48 sh
> 12937 12936 12937     0  Ss+     wait     0xc4ff9d48 make
> 12936  3722  3722     0  R+                          script
> 3722  2021  3722     0  S+      (threaded)          ruby18
> 100132                   S       wait     0xc4ffa7f8 ruby18
> 2404  2007  2404  1000  Ss+     ttyin    0xc4d74870 zsh
> 2325  2015  2325  1000  R+                          top
> 2021  2009  2021     0  S+      pause    0xc4ff9058 csh
> 2015  2007  2015  1000  Ss+     pause    0xc4ffa058 zsh
> 2009  2007  2009  1000  Ss+     pause    0xc4d4e850 zsh
> 2007  2006  2007  1000  Rs                          screen
> 2006  1991  2006  1000  R+                          screen
> 2005  2001  2005     0  R+                          systat
> 2001  1976  2001     0  S+      pause    0xc3d52058 csh
> 2000     1  2000     0  Ss      select   0xc3d5b1a4 ssh-agent
> 1991  1990  1991  1000  Ss+     pause    0xc3d52850 zsh
> 1990  1986  1986  1000  S       select   0xc3d5aca4 sshd
> 1989     1  1989  1000  Ss      select   0xc3d5ae24 ssh-agent
> 1986  1884  1986     0  Ss      sbwait   0xc4f2058c sshd
> 1985     1  1985     0  Ss+     ttyin    0xc3e62670 getty
> 1984     1  1984     0  Ss+     ttyin    0xc3e61c70 getty
> 1983     1  1983     0  Ss+     ttyin    0xc3e60070 getty
> 1982     1  1982     0  Ss+     ttyin    0xc3e60a70 getty
> 1981     1  1981     0  Ss+     ttyin    0xc3da7a70 getty
> 1980     1  1980     0  Ss+     ttyin    0xc3da7c70 getty
> 1979     1  1979     0  Ss+     ttyin    0xc3e60c70 getty
> 1976     1  1976     0  Ss+     wait     0xc4c392a8 login
> 1955     1  1955     0  Rs                          bsnmpd
> 1931     1  1931     0  Ss      select   0xc4d0f164 inetd
> 1890     1  1890     0  Rs                          cron
> 1884     1  1884     0  Ss      select   0xc4d0eda4 sshd
> 1808     1  1808     0  Rs                          sendmail
> 1764     1  1764     0  Rs                          moused
> 1754     1  1754     0  Ss      (threaded)          nslcd
> 100111                   S       accept   0xc4d076ae nslcd
> 100110                   S       accept   0xc4d076ae nslcd
> 100109                   S       accept   0xc4d076ae nslcd
> 100108                   S       accept   0xc4d076ae nslcd
> 100107                   S       accept   0xc4d076ae nslcd
> 100076                   S       uwait    0xc4493180 nslcd
> 1748     1  1748     0  Rs                          openvpn
> 1724     1  1724   201  Ss      accept   0xc4d07b82 privoxy
> 1672     1  1672     0  Rs                          powerd
> 1664     1  1664     0  Rs                          ntpd
> 1658     1  1658     0  Ss      (threaded)          nscd
> 100094                   S       kqread   0xc4cf1700 nscd
> 100093                   S       kqread   0xc4cf1700 nscd
> 100092                   S       kqread   0xc4cf1700 nscd
> 100091                   S       kqread   0xc4cf1700 nscd
> 100090                   S       kqread   0xc4cf1700 nscd
> 100089                   S       kqread   0xc4cf1700 nscd
> 100088                   S       kqread   0xc4cf1700 nscd
> 100087                   S       kqread   0xc4cf1700 nscd
> 100075                   S       uwait    0xc449f680 nscd
> 1576     1  1576   389  Ss      (threaded)          slapd
> 100115                   S       ucond    0xc4cf2700 slapd
> 100086                   S       ucond    0xc4cf2600 slapd
> 100085                   S       select   0xc4d0eea4 slapd
> 100073                   S       uwait    0xc42a9580 slapd
> 1563     1  1562     0  S       nanslp   0xc09f3864 smartd
> 1526     1  1526     0  Rs                          rpc.statd
> 1445     1  1445     0  Rs                          amd
> 1418     1  1418     0  Rs                          rpcbind
> 1403     1  1403    53  Ss      (threaded)          named
> 100084                   S       kqread   0xc4cdcb80 named
> 100083                   S       ucond    0xc4260b00 named
> 100082                   S       ucond    0xc449fb80 named
> 100074                   S       sigwait  0xfb4b8be0 named
> 1306     1  1306     0  Rs                          syslogd
>  997     0     0     0  RL                          [pfpurge]
>  973     1   973     0  Ss      select   0xc41eb0a4 devd
>  964     1   964    65  Ss      select   0xc44ac524 dhclient
>  942     1   942     0  Ss      select   0xc426f424 dhclient
>  856     1   856     0  Ss      select   0xc41eb424 moused
>  561     1   561     0  Ss      select   0xc44acde4 wpa_supplicant
>  150     1   150     0  Ss      pause    0xc42ec850 adjkerntz
>   95     0     0     0  DL      mdwait   0xc426a000 [md0]
>   74     0     0     0  DL      geli:w   0xc4265400 [g_eli[0] ad0s4f]
>   22     0     0     0  RL                          [softdepflush]
>   21     0     0     0  RL                          [syncer]
>   20     0     0     0  RL                          [vnlru]
>   19     0     0     0  RL                          [bufdaemon]
>   18     0     0     0  RL                          [pagezero]
>   17     0     0     0  DL      psleep   0xc0b769d8 [vmdaemon]
>   16     0     0     0  RL                          [pagedaemon]
>    9     0     0     0  DL      ccb_scan 0xc09d78d4 [xpt_thrd]
>   15     0     0     0  DL      tzpoll   0xc09dafcc [acpi_thermal]
>    8     0     0     0  SL      -        0xc3f55000 [fw0_probe]
>    7     0     0     0  DL      -        0xc3ebd3bc [cbb0 event thread]
>   14     0     0     0  DL      (threaded)          [usb]
> 100040                   D       -        0xc3f39d0c [usbus3]
> 100039                   D       -        0xc3f39cdc [usbus3]
> 100038                   D       -        0xc3f39cac [usbus3]
> 100037                   D       -        0xc3f39c7c [usbus3]
> 100036                   D       -        0xc3f1fdac [usbus2]
> 100035                   D       -        0xc3f1fd7c [usbus2]
> 100034                   D       -        0xc3f1fd4c [usbus2]
> 100033                   D       -        0xc3f1fd1c [usbus2]
> 100032                   D       -        0xc3f0ddac [usbus1]
> 100031                   D       -        0xc3f0dd7c [usbus1]
> 100030                   D       -        0xc3f0dd4c [usbus1]
> 100029                   D       -        0xc3f0dd1c [usbus1]
> 100028                   D       -        0xc3ef7dac [usbus0]
> 100027                   D       -        0xc3ef7d7c [usbus0]
> 100026                   D       -        0xc3ef7d4c [usbus0]
> 100025                   D       -        0xc3ef7d1c [usbus0]
>    6     0     0     0  DL      crypto_r 0xc0b7446c [crypto returns]
>    5     0     0     0  DL      crypto_w 0xc0b74448 [crypto]
>   13     0     0     0  DL      -        0xc09f36c4 [yarrow]
>    4     0     0     0  DL      -        0xc09f13e4 [g_down]
>    3     0     0     0  DL      -        0xc09f13e0 [g_up]
>    2     0     0     0  RL                          [g_event]
>   12     0     0     0  RL      (threaded)          [intr]
> 100049                   I                           [irq12: psm0]
> 100048                   I                           [irq1: atkbd0]
> 100046                   I                           [irq15: ata1]
> 100045                   I                           [irq14: ata0]
> 100024                   I                           [irq11: cbb0 bfe0++*]
> 100023                   I                           [irq9: pcm0 iwi0+]
> 100022                   I                           [swi6: Giant taskq]
> 100020                   I                           [swi5: +]
> 100019                   I                           [swi2: cambio]
> 100014                   I                           [swi6: task queue]
> 100006                   I                           [swi3: vm]
> 100005                   Run     CPU 0               [swi4: clock]
> 100004                   I                           [swi1: netisr 0]
>   11     0     0     0  RL                          [idle: cpu0]
>    1     0     1     0  SLs     wait     0xc3df2d48 [init]
>   10     0     0     0  DL      audit_wo 0xc0b747e0 [audit]
>    0     0     0     0  RLs     (threaded)          [kernel]
> 100050                   D       deadlkre 0xc09f36c4 [deadlkres]
> 100044                   D       -        0xc3f5db80 [iwi0 taskq]
> 100042                   D       -        0xc3f5e8c0 [fw0_taskq]
> 100021                   D       -        0xc3ea08c0 [thread taskq]
> 100018                   D       -        0xc3ea0a80 [kqueue taskq]
> 100017                   D       -        0xc3ea0c40 [acpi_task_2]
> 100016                   D       -        0xc3ea0c40 [acpi_task_1]
> 100015                   D       -        0xc3ea0c40 [acpi_task_0]
> 100010                   D       -        0xc3dda9c0 [firmware taskq]
> 100000                   RunQ                        [swapper]
> 1999  1976  1976     0  Z+                          ssh-agent
> 1988  1986  1986  1000  Z                           ssh-agent
> db> show alllocks
> Process 13467 (mkdir) thread 0xc543b270 (100150)
> exclusive lockmgr bufwait (bufwait) r = 0 (0xebd1f8ec) locked @ /usr/src/sys/kern/vfs_bio.c:2581
> exclusive lockmgr ufs (ufs) r = 0 (0xc542fc08) locked @ /usr/src/sys/kern/vfs_subr.c:2091
> exclusive lockmgr bufwait (bufwait) r = 0 (0xebd15194) locked @ /usr/src/sys/ufs/ffs/ffs_softdep.c:11363
> exclusive lockmgr ufs (ufs) r = 0 (0xc54279e8) locked @ /usr/src/sys/kern/vfs_lookup.c:502
> Process 1986 (sshd) thread 0xc4d2ec30 (100113)
> exclusive sx so_rcv_sx (so_rcv_sx) r = 0 (0xc4f20560) locked @ /usr/src/sys/kern/uipc_sockbuf.c:148
> Process 22 (softdepflush) thread 0xc428f750 (100058)
> exclusive sleep mutex struct mount mtx (struct mount mtx) r = 0 (0xc42a3a20) locked @ /usr/src/sys/kern/vfs_subr.c:341
> Process 12 (intr) thread 0xc3df44e0 (100005)
> exclusive sleep mutex ttymtx (ttymtx) r = 0 (0xc3e63604) locked @ /usr/src/sys/dev/dcons/dcons_os.c:232
> db> show pcpu
> cpuid        = 0
> dynamic pcpu    = 0x64e400
> curthread    = 0xc3df44e0: pid 12 "swi4: clock"
> curpcb       = 0xc3bfbd90
> fpcurthread  = none
> idlethread   = 0xc3df49c0: pid 11 "idle: cpu0"
> APIC ID      = 0
> currentldt   = 0x50
> spin locks held:
> db> show lockedvnods
> Locked vnodes
>
> 0xc5427990: tag ufs, type VDIR
>    usecount 5, writecount 0, refcount 7 mountedhere 0
>    flags ()
>    v_object 0xc54224c8 ref 0 pages 0
>    lock type ufs: EXCL by thread 0xc543b270 (pid 13467)
>        ino 11375831, on dev ad0s4f.eli
>
> 0xc542fbb0: tag ufs, type VREG
>    usecount 2, writecount 0, refcount 5 mountedhere 0
>    flags ()
>    v_object 0xc5422880 ref 0 pages 7
>    lock type ufs: EXCL by thread 0xc543b270 (pid 13467)
>        ino 11375884, on dev ad0s4f.eli
> db> alltrace
>
> Tracing command mkdir pid 13467 tid 100150 td 0xc543b270
> sched_switch(c543b270,0,104,191,f614b28d,...) at sched_switch+0x36a
> mi_switch(104,0,c093a853,1eb,4c,...) at mi_switch+0x200
> sleepq_switch(c543b270,0,c093a853,260,0,...) at sleepq_switch+0x15f
> sleepq_wait(ebd1f88c,4c,c0941795,0,0,...) at sleepq_wait+0x63
> _sleep(ebd1f88c,c3da14ac,4c,c0941795,0,...) at _sleep+0x365
> bwait(ebd1f88c,4c,c0941795,ebd1f88c,fb5d5584,...) at bwait+0x6f
> bufwait(ebd1f88c,ebd1f88c,0,ebd1f88c,c54165e4,...) at bufwait+0x48
> bufwrite(ebd1f88c,0,c09625e3,74d,0) at bufwrite+0x165
> ffs_bufwrite(ebd1f88c,c542d500,100,4000,0,...) at ffs_bufwrite+0x290
> ffs_update(c542fbb0,1,80000,fb5d567c,1,...) at ffs_update+0x27c
> softdep_sync_metadata(c5427990,0,c0962b76,144,0,...) at softdep_sync_metadata+0xc9f
> ffs_syncvnode(c5427990,1,c543b270,fb5d573c,246,...) at ffs_syncvnode+0x3e2
> ffs_truncate(c5427990,400,0,880,c4c4f680,...) at ffs_truncate+0x862
> ufs_direnter(c5427990,c542f660,fb5d5a1c,fb5d5c00,ebd2a930,...) at ufs_direnter+0x8d4
> ufs_mkdir(fb5d5c28,fb5d5c3c,0,fb5d5bd4,fb5d5b6c,...) at ufs_mkdir+0x81f
> VOP_MKDIR_APV(c09bd840,fb5d5c28,68,fb5d5bc0,0,...) at VOP_MKDIR_APV+0xa5
> kern_mkdirat(c543b270,ffffff9c,bfbfeaa2,0,1ff,...) at kern_mkdirat+0x211
> kern_mkdir(c543b270,bfbfeaa2,0,1ff,fb5d5d2c,...) at kern_mkdir+0x2e
> mkdir(c543b270,fb5d5cf8,c,c,c5434aa0,...) at mkdir+0x29
> syscall(fb5d5d38) at syscall+0x220
> Xint0x80_syscall() at Xint0x80_syscall+0x20
> --- syscall (136, FreeBSD ELF32, mkdir), eip = 0x28178ef3, esp = 0xbfbfe7ec, ebp = 0xbfbfe8b8 ---
>
> Tracing command sh pid 13444 tid 100147 td 0xc4fff9c0
> sched_switch(c4fff9c0,0,104,191,f5d80613,...) at sched_switch+0x36a
> mi_switch(104,0,c093a853,1eb,5c,...) at mi_switch+0x200
> sleepq_switch(c4fff9c0,0,c093a853,1a0,5c,...) at sleepq_switch+0x15f
> sleepq_catch_signals(c093a853,160,0,100,100,...) at sleepq_catch_signals+0xb7
> sleepq_wait_sig(c54352a8,5c,c093d112,100,0,...) at sleepq_wait_sig+0x17
> _sleep(c54352a8,c5435330,15c,c093d112,0,...) at _sleep+0x34e
> kern_wait(c4fff9c0,ffffffff,fb5ccc74,2,0,...) at kern_wait+0xb76
> wait4(c4fff9c0,fb5cccf8,c0972944,c093d0f1,c54352a8,...) at wait4+0x3d
> syscall(fb5ccd38) at syscall+0x220
> Xint0x80_syscall() at Xint0x80_syscall+0x20
> --- syscall (7, FreeBSD ELF32, wait4), eip = 0x281681eb, esp = 0xbfbfe5bc, ebp = 0xbfbfe5d8 ---
>
>
> <snip>
> I hope you don't really need all of the traces, I'll keep the system at
> the DDB prompt for now, so I can do other stuff.

I really need any trace that is involved in vfs.  Is this machine hooked 
to a serial console for ddb so you can pipe output to a file with 
script(1)?  I understand the paths that hold the locks but I don't 
understand who is deadlocked against it.  It looks like the thread that is 
holding the locks is just waiting on io to complete.  So something that 
completes IO is hung.

The earlier deadlock you reported should have actually been there for 
years.  It only happens when a directory is truncated though which is 
infrequent so it may not have been reported.

Thanks,
Jeff

>
> Regards,
> Uli
> _______________________________________________
> freebsd-current@freebsd.org mailing list
> http://lists.freebsd.org/mailman/listinfo/freebsd-current
> To unsubscribe, send any mail to "freebsd-current-unsubscribe@freebsd.org"
>
--2547152148-1124801055-1273360782=:1398--



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