On Mon 03-09-07 05:49:59, Andrew Morton wrote: > > On Mon, 3 Sep 2007 14:27:02 +0200 Jan Kara <[EMAIL PROTECTED]> wrote: > > > > On Fri, 24 Aug 2007 23:00:33 +0200 Folkert van Heusden <[EMAIL > > > > PROTECTED]> wrote: > > > > Hi, > > > > > > > > 2.6.22 kernel with hyperthreading enabled only ext3 filesystems (2). > > > > > > > > [ 346.314640] ======================================================= > > > > [ 346.314758] [ INFO: possible circular locking dependency detected ] > > > > [ 346.314815] 2.6.22 #5 > > > > [ 346.314862] ------------------------------------------------------- > > > > [ 346.314920] tor/2421 is trying to acquire lock: > > > > [ 346.314973] (tty_mutex){--..}, at: [<c121aa83>] mutex_lock+0x8/0xa > > > > [ 346.315193] > > > > [ 346.315195] but task is already holding lock: > > > > [ 346.316203] (&s->s_dquot.dqptr_sem){----}, at: [<c10a485f>] > > > > dquot_alloc_space+0x50/0x189 > > > > [ 346.316457] > > > > [ 346.316458] which lock already depends on the new lock. > > > > ... > > > > > > [ 346.353603] ======================= > > > > > > > Has been reported before, but I don't recall whether we fixed it. Jan, > > > do you know>? > > I think we at least found a solution: Teach lockdep that I_MUTEX for > > different filesystems is different. Peter Zilstra wrote a patch for that > > and Folkert even confirmed that it fixes the problem for him. I'm not > > sure what happened with the patch afterwards though. Adding Peter to CC > > :). > > But this is a tty_lock-versus-dqptr_sem ranking error. Unrelated to i_mutex? The final report is for this ranking but the locking chain (if I understand it right) is: tty_mutex (con_close) -> i_mutex (sysfs: remove_subdir) i_mutex (do_truncate) -> i_alloc_sem (notify_change) -> truncate_mutex (ext3_truncate) truncate_mutex (ext3_get_blocks_handle) -> dqptr_sem (dquot_alloc_space)
So it complains about tty_mutex vs dqptr_sem (I don't know why it does not complain about tty_mutex vs i_mutex) but the wrong link in the chain is that i_mutex from remove_subdir() [sysfs] and i_mutex from do_truncate() [ext3] are different and should never depend on each other... Honza -- Jan Kara <[EMAIL PROTECTED]> SuSE CR Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/