On Tue, Aug 04, 2009 at 11:56:48AM +0200, Juergen Unger wrote:
quoted text
> On Tue, Aug 04, 2009 at 11:49:50AM +0200, Pawel Jakub Dawidek wrote:
> > > testbox# sysctl debug.kdb.enter=3D1
> > > KDB: enter: sysctl debug.kdb.enter
> > > [thread pid 11635 tid 100472 ]
> > > Stopped at      kdb_enter+0x3a: movl    __PLACEHOLDER__0_,kdb_why
> > > db> show lock 0x87aac290
> > >  class: sx
> > >  name: dp->dp_config_rwlock
> > >  state: XLOCK: 0x879e8480 (tid 100130, pid 172, "txg_thread_enter")
> > >  waiters: shared
> > > db>=20
> >=20
> > Could you also try something like the following from DDB:
> >=20
> > 	x/bx 0x879ad8a0,52
>=20
> db> x/bx 0x879ad8a0,52
> 0x879ad8a0:     82  1a  4b  87  0   0   71  2   0   0   0   0   0   0   0=
   0
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> 0x879ad8b0:     1   0   0   0   91  1a  4b  87  4   0   0   0   40  92  c=
b  87
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> 0x879ad8c0:     0   0   0   0   0   0   0   0   0   0   0   0   0   0   0=
   0
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> 0x879ad8d0:     0   0   0   0   9   1f  4b  87  0   0   71  2   0   0   0=
   0
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> 0x879ad8e0:     0   0   0   0   40  92  cb  87  e8  0   0   0   c8  0   0=
   0
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> 0x879ad8f0:     a8  bb
> db>

This is dump of ZFS-specific rrwlock that some threads are waiting for.
We can see here that thread owning the lock is 0x87cb9240, which is pid
86397 (zfs recv process). I don't think we will be able to gather more
info from here. I'm builing HEAD at the moment and hopefully will be
able to reproduce it. Thanks for all the info.

--=20
Pawel Jakub Dawidek                       http://www.wheel.pl
pjd@FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!