Re: [crash, bisected] I2C, kobject (ffff81003e8c4160): tried to init an initialized object

[Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org>]

* Alexey Dobriyan <adobriyan-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:

> On Thu, Jul 17, 2008 at 11:33:30AM +0200, Ingo Molnar wrote:
> > 
> > * Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org> wrote:
> > 
> > > Jean,
> > > 
> > > -tip testing found another (similar) i2c crash with latest -git, on a 
> > > Core2Duo laptop:
> > > 
> > > calling  nforce2_init+0x0/0x1b
> > > initcall nforce2_init+0x0/0x1b returned 0 after 0 msecs
> > > calling  nforce2_s4985_init+0x0/0x275
> > > BUG: unable to handle kernel NULL pointer dereference at 0000000c
> > > IP: [<c04af2cf>] i2c_smbus_xfer+0x27/0x3f0
> > > *pdpt = 00000000009cb001 *pde = 0000000000000000 
> > > Oops: 0000 [#1] SMP 
> > 
> > turning off I2C_NFORCE2_S4985 makes the system boot up fine. Workaround 
> > patch below.
> 
> Well, it's pretty easy oops unless I misread something.
> It happened on not nforce2 motherboard, right?

yeah.

> nforce2_init will just register PCI driver,
> no matching PCI ids => nforce2_set_reference() isn't called =>
> nforce2_smbus stays NULL.
> 
> Second module loads and tries to i2c_smbus_xfer(NULL, ) in module_init()
> hook which oopses.

can try patches, but got other 5 fresh upstream oopses/hangs/crashes to 
investigate now. (so i went for the minimal-effort 
turn-off-the-failing-part approach)

	Ingo

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