Re: 2.6.24-rc2-mm1

[Greg KH <greg@kroah.com>]

On Wed, Nov 14, 2007 at 06:02:07PM +0100, Jiri Kosina wrote:
> On Wed, 14 Nov 2007, Jiri Kosina wrote:
> 
> > > I'd suspect the driver tree.  I think I'll need to do a quick -mm2 
> > > without that tree present.
> > I am just verifying whether reverting kset changes fixes this, will let 
> > you know soon.
> 
> OK, so I reverted 
> gregkh-driver-kset-convert-block_subsys-to-use-kset_create (which made me 
> also revert gregkh-driver-kobject-remove-subsystem_register-functions and 
> gregkh-driver-kset-remove-decl_subsys-macro so that we compile). Both the 
> error message from lockdep and more importantly the spinlock lockup have 
> gone, and the system with these patches reverted boots for me fine.
> 
> Well not that fine, I still see (which is the same backtrace that caused 
> the lockup with plain -rc2-mm1, but doesn't make the machine hang):
> 
> floppy0: Floppy io-port 0x03f2 in use
> WARNING: at lib/kref.c:33 kref_get()
> 
> Call Trace:
>  [<ffffffff8035bd43>] kobject_add+0x9b/0x197
>  [<ffffffff8035c6e1>] kref_get+0x2f/0x36
>  [<ffffffff8035b82f>] kobject_get+0x12/0x17
>  [<ffffffff8035bd55>] kobject_add+0xad/0x197
>  [<ffffffff802c9a36>] register_disk+0x48/0x205
>  [<ffffffff80355cf3>] add_disk+0x34/0x3d
>  [<ffffffff8083cd99>] rd_init+0x172/0x1e1
>  [<ffffffff8082063a>] kernel_init+0x175/0x2e6
>  [<ffffffff8025193c>] trace_hardirqs_on+0x115/0x139
>  [<ffffffff80598769>] trace_hardirqs_on_thunk+0x35/0x3a
>  [<ffffffff8025193c>] trace_hardirqs_on+0x115/0x139
>  [<ffffffff8020c628>] child_rip+0xa/0x12
>  [<ffffffff8020bd3f>] restore_args+0x0/0x30
>  [<ffffffff808204c5>] kernel_init+0x0/0x2e6
>  [<ffffffff8020c61e>] child_rip+0x0/0x12

someone is trying to call kref_get on a kobject that has not been
initialized yet, which could be the reason the newer patches break
something, as the pointers are not set up properly with a call to
kobject_init() first.

But, alloc_disk() should have been called on this gendisk for it to work
properly at all, unless something is trashing that structure?

I'm way confused...

greg k-h
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