Re: Panic from mptspi_dv_renegotiate_work in 2.6.18-mm2

[Andrew Morton <akpm@osdl.org>]

On Mon, 2 Oct 2006 17:21:08 -0600
"Moore, Eric" <Eric.Moore@lsil.com> wrote:

> On Monday, October 02, 2006 2:40 PM, Andrew Morton wrote: 
> 
> > 
> > Yeah, Bryce@osdl is hitting this.  Apparently it can be worked around
> > by compiling the driver as a module.
> >
> 
> What I saw in Bryces trace was the driver was not receiving interrupts
> for
> the first command sent after interrutps were enabled.  This was a config
> page
> for spi port pages.  Since this command timed out, an internal timeout
> handler was called,
> and we issued an internal host reset.  The host reset called each
> driver,
> such as mptspi, mptfc, mptsas,  callback handers.  That ended with
> as pacin in mptspi, due to we assume ioc->hd to be a valid pointer.  
> We don't allocate ioc->hd to well after mpt_attach, which is where the
> config
> page that timed out.    We could prevent the panic in mptspi, but that 
> doesn't fix the problem why we are not getting interrupts.   
> 
> I have a 2.6.18 gold kernel, and that works fine with modules.  
> There are no changes in mpt stack since 2.6.18 that would effect
> interrupts.  
> Do you know of any changes in kernel effecting interrupts?   I suspect
> that
> modules versus linked drivers into kernel would matter, or would it?

There are lots and lots of interrupt changes, some now in mainline, some
not.

There's a known-problematic PCI resource allocation bug now in mainline
too.  It appears that this can cause devices to not get assigned an
interrupt.

So yes, this is probably the trigger.  But as a secondary thing, it appears
that the driver will crash if something goes wrong with the interrupt
setup?