Re: INFO: possible circular locking dependency detected

From: Randy Dunlap
Date: Mon Oct 16 2006 - 11:43:25 EST


On Tue, 17 Oct 2006 00:32:44 +1000 Nick Piggin wrote:

> alpha @ steudten Engineering wrote:
> > =======================================================
> > [ INFO: possible circular locking dependency detected ]
> > 2.6.18-1.2189self #1
> > -------------------------------------------------------
> > kswapd0/186 is trying to acquire lock:
> > (&inode->i_mutex){--..}, at: [<c0326e32>] mutex_lock+0x21/0x24
> >
> > but task is already holding lock:
> > (iprune_mutex){--..}, at: [<c0326e32>] mutex_lock+0x21/0x24
> >
> > which lock already depends on the new lock.
>
> Thanks. __grab_cache_page wants to clear __GFP_FS, because it is
> holding the i_mutex so we don't want to reenter the filesystem in
> page reclaim.
>
> This would be an easy two liner, except those funny page_cache_alloc
> routines which take a mapping rather than a gfp_t argument :P

and it would be only one email, but you forgot spaces there,
so it's too ugly to use. ;) i.e., please add spaces around
the '&'.

and it's an attachment :(

> Anyway, I'll get around to writing the real patch and queue it up
> with my other buffered write deadlock fixes. It should be fairly
> unlikely to cause you a deadlock. You could give this quick patch a
> try, though. Does it fix your problem?



---
~Randy
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