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* Re: RCU locking issues in jbd2_dev_to_name
       [not found] <20110727174104.65fb9c1c@notabene.brown>
@ 2011-07-27 11:28 ` Theodore Tso
  2011-07-27 22:45   ` NeilBrown
  0 siblings, 1 reply; 2+ messages in thread
From: Theodore Tso @ 2011-07-27 11:28 UTC (permalink / raw)
  To: NeilBrown; +Cc: linux-ext4, Paul E.McKenney


On Jul 27, 2011, at 3:41 AM, NeilBrown wrote:

> 
> 
> Hi Ted and all,
> 
> I've been exploring RCU usage in the kernel looking for strange things, and
> jbd2_dev_to_name looks particularly strange.  The following patch explains
> and addresses the issues that I found.  Comments welcome.

Yeah its broken.  But I have patches pending for the merge window that solve
it by nuking the function altogether; the problem is calling a function from
TP_PRINTK causes perf to die on the spot, terminating its tracing.  :-(

- Ted


^ permalink raw reply	[flat|nested] 2+ messages in thread

* Re: RCU locking issues in jbd2_dev_to_name
  2011-07-27 11:28 ` RCU locking issues in jbd2_dev_to_name Theodore Tso
@ 2011-07-27 22:45   ` NeilBrown
  0 siblings, 0 replies; 2+ messages in thread
From: NeilBrown @ 2011-07-27 22:45 UTC (permalink / raw)
  To: Theodore Tso; +Cc: linux-ext4, Paul E.McKenney

On Wed, 27 Jul 2011 07:28:27 -0400 Theodore Tso <tytso@MIT.EDU> wrote:

> 
> On Jul 27, 2011, at 3:41 AM, NeilBrown wrote:
> 
> > 
> > 
> > Hi Ted and all,
> > 
> > I've been exploring RCU usage in the kernel looking for strange things, and
> > jbd2_dev_to_name looks particularly strange.  The following patch explains
> > and addresses the issues that I found.  Comments welcome.
> 
> Yeah its broken.  But I have patches pending for the merge window that solve
> it by nuking the function altogether; the problem is calling a function from
> TP_PRINTK causes perf to die on the spot, terminating its tracing.  :-(
> 

Sounds painful...

If it is about to go, that is good enough for me.

Thanks,
NeilBrown

^ permalink raw reply	[flat|nested] 2+ messages in thread

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2011-07-27 11:28 ` RCU locking issues in jbd2_dev_to_name Theodore Tso
2011-07-27 22:45   ` NeilBrown

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