Re: 2.6.18-git21, possible recursive locking in kseriod ends up in DWARF2 unwinder stuck

[Dmitry Torokhov]

On 10/4/06, Jiri Kosina <jikos@xxxxxxxx> wrote:
> On Wed, 4 Oct 2006, Alessandro Suardi wrote:
>
> > Non-fatal (box is still alive and apparently well) on boot,
> > FC5-uptodate on a Dell Latitude C640. From the dmesg ring:
>
> > [    8.680000] =============================================
> > [    8.680000] [ INFO: possible recursive locking detected ]
> > [    8.680000] 2.6.18-git21 #1
> > [    8.680000] ---------------------------------------------
> > [    8.680000] kseriod/163 is trying to acquire lock:
> > [    8.680000]  (&ps2dev->cmd_mutex/1){--..}, at: [<c03198c3>]
> > ps2_command+0x89/0x358
>
> Me and Peter Zijlstra have already submitted patches to fix this - read
> the thread at
> http://linux.derkeiler.com/Mailing-Lists/Kernel/2006-09/msg07416.html
>
> I don't know the reason why these have not yet been merged into the input
> tree. Dmitry?

Sorry, was a little busy.

I tested the patches and they work. Couple of comments:

- register_lock_class is marked as inline but now has 2 call sites and
is relatively big - might want to remove "inline"
- how about adding lockdep_set_subclass() to avoid littering source
with struct lock_class_key when we only want to tweak subclass? For
that we might want export register_lock_class and hide it behind a
#define...

--
Dmitry
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