Re: 2.6.17-rc5-mm3: bad unlock ordering (reiser4?)

[Ingo Molnar <mingo@elte.hu>]

* Barry K. Nathan <barryn@pobox.com> wrote:

> On 6/4/06, Ingo Molnar <mingo@elte.hu> wrote:
> >reporting the first one only is necessary, because the validator cannot
> >trust a system's dependency info that it sees as incorrect. Deadlock
> >possibilities are quite rare in a kernel that is "in balance". Right now
> >we are not "in balance" yet, because the validator has only been added a
> >couple of days ago. The flurry of initial fixes will die down quickly.
> 
> So, does that mean the plan is to annotate/tweak things in order to 
> shut up *each and every* false positive in the kernel?

yes. Note that for the many reasons i outlined before they are only 
"half false positives" - i.e. they are potentially dangerous constructs 
and they are potentially inefficient - hence we _want to_ document them 
in the code, to increase the cleanliness of the kernel. A pure "false 
positive" would be a totally valid and perfect locking construct being 
flagged by the lock validator.

nor do these warnings really hurt anyone. Lockdep prints info and then 
shuts up - the system continues to work.

> Anyway, I tried your patch and I got this:

please try the addon patch below.

	Ingo

Index: linux/fs/reiser4/txnmgr.h
===================================================================
--- linux.orig/fs/reiser4/txnmgr.h
+++ linux/fs/reiser4/txnmgr.h
@@ -567,7 +567,7 @@ static inline void spin_unlock_txnh(txn_
 	LOCK_CNT_DEC(spin_locked_txnh);
 	LOCK_CNT_DEC(spin_locked);
 
-	spin_unlock(&(txnh->hlock));
+	spin_unlock_non_nested(&(txnh->hlock));
 }
 
 #define spin_ordering_pred_txnmgr(tmgr)		\