Re: Question on lockdep and sysrq - d

[Ben Greear]

Ming Lei wrote:
> See http://marc.info/?l=linux-kernel&m=124211522525625&w=2.
>   
That is about some real bug in the official kernel.  I am almost 100%
certain that my own code is at fault here.

I'm just trying to better understand the way lockdep prints out
all of the locks so I can easier debug my issue.

Thanks,
Ben

> thanks.
>
> 2009/5/23 Ben Greear <greearb@xxxxxxxxxxxxxxx>:
>   
> > Hello!
> >
> > I'm trying to debug an apparent deadlock in some code I'm
> > writing.
> >
> > When I do a sysrq 'd', I get a nice dump of locks (I have lockdep enabled).
> >
> > However, the output appears to show multiple processes holding the
> > same locks (rtnl_mutex, for example):
> >
> > Showing all locks held in the system:
> > 3 locks held by events/11/63:
> >  #0:  (events){--..}, at: [<ffffffff8104f71e>] run_workqueue+0xb1/0x216
> >  #1:  ((linkwatch_work).work){--..}, at: [<ffffffff8104f71e>]
> > run_workqueue+0xb1/0x216
> >  #2:  (rtnl_mutex){--..}, at: [<ffffffff8125def1>] rtnl_lock+0x12/0x14
> > 1 lock held by irqbalance/3360:
> >  #0:  (rtnl_mutex){--..}, at: [<ffffffff8125def1>] rtnl_lock+0x12/0x14
> > 1 lock held by hald/3605:
> >  #0:  (rtnl_mutex){--..}, at: [<ffffffff8125def1>] rtnl_lock+0x12/0x14
> > ...
> >
> > Is this merely showing processes that are blocked on trying to acquire these
> > locks?
> >
> > If so, is there any way to tell which processes have fully acquired locks
> > v/s
> > just waiting to acquire them?
> >
> > Thanks,
> > Ben
> >     

--
Ben Greear <greearb@xxxxxxxxxxxxxxx> 
Candela Technologies Inc  http://www.candelatech.com


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