Re: Panic from mptspi_dv_renegotiate_work in 2.6.18-mm2

From: Jeff Garzik
Date: Mon Oct 02 2006 - 20:32:46 EST

Andrew Morton wrote:
On Mon, 2 Oct 2006 17:21:08 -0600
"Moore, Eric" <Eric.Moore@xxxxxxxx> 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?

FWIW, I am seeing precisely this problem, in the latest -git.

Jeff



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