[nfs] process locks in "bo_wwait" on 6.4

[pluknet]

2009/6/29 Attilio Rao <attilio at freebsd.org>:
> 2009/6/29 pluknet <pluknet at gmail.com>:
>> 2009/6/29 Attilio Rao <attilio at freebsd.org>:
>>> 2009/6/29 pluknet <pluknet at gmail.com>:
>>>> 2009/6/29 Attilio Rao <attilio at freebsd.org>:
>>>>> 2009/6/29 pluknet <pluknet at gmail.com>:
>>>>>> 2009/6/29 Attilio Rao <attilio at freebsd.org>:
>>>>>>> 2009/6/29 pluknet <pluknet at gmail.com>:
>>>>>>>> 2009/6/26 pluknet <pluknet at gmail.com>:
>>>>>>>>> 2009/6/26 pluknet <pluknet at gmail.com>:
>>>>>>>>>> Hello.
>>>>>>>>>>
>>>>>>>>>> While building a module on nfs mounted /usr/src
>>>>>>>>>> I got an unkillable process waiting forever in bo_wwait.
>>>>>>>>>
>>>>>>>>> Small note: iface on NFS server has mtu changed from 1500 to 1450.
>>>>>>>>> Can this be a source of the problem?
>>>>>>>>
>>>>>>>> This is 100% reproducible. Lock in the same place. Any hints?
>>>>>>>
>>>>>>> Can you also show the value of ps?
>>>>>>> A precise map of what processes are doing would give an help.
>>>>>>> Also would be useful to printout traces for other threads and not only
>>>>>>> the stucked one.
>>>>>>>
>>>>>>
>>>>>> >From another run:
>>>>>
>>>>> I'm unable to see who would be locking the buffer object in question.
>>>>> Do you have INVARIANT_SUPPORT/INVARIANTS on?
>>>>
>>>> Yes, I do both.
>>>>
>>>>> What revision of /usr/src/sys/kern/vfs_bio.c are you running with?
>>>>>
>>>>
>>>> As of 6.4-R: CVS rev 1.491.2.12.4.1 / SVN rev 183531.
>>>
>>> Please try this patch and report.
>>>
>>> Thanks,
>>> Attilio
>>>
>>> --- src/sys/nfsclient/nfs_vnops.c       2008/02/13 20:44:18     1.281
>>> +++ src/sys/nfsclient/nfs_vnops.c       2008/03/22 09:15:15     1.282
>>> @@ -33,7 +33,7 @@
>>>  */
>>>
>>>  #include <sys/cdefs.h>
>>> -__FBSDID("$FreeBSD:
>>> /usr/local/www/cvsroot/FreeBSD/src/sys/nfsclient/nfs_vnops.c,v 1.281
>>> 2008/02/13 20:44:18 attilio Exp $");
>>> +__FBSDID("$FreeBSD:
>>> /usr/local/www/cvsroot/FreeBSD/src/sys/nfsclient/nfs_vnops.c,v 1.282
>>> 2008/03/22 09:15:15 jeff Exp $");
>>>
>>
>> Do you refer to the whole svn r177493, or is its nfs part will be enough?
>> This only vfs_vnops.c diff seems not applicable without underneath
>> kernel part changes.
>>
>> I'll try. Thanks.
>
> The NFS part should be enough, though I don't understand why it
> doesn't trigger a panic on STABLE_6 as long as, at least in my
> revision, there is an assert for the buffer object lock to be held in
> bufobj_wwait(). What's your sys/kern/vfs_bio.c rev?
>

As of 6.4-R.
$FreeBSD: src/sys/kern/vfs_bio.c,v 1.491.2.12.4.1 2008/10/02 02:57:24
kensmith Exp $

-- 
wbr,
pluknet