[PATCH] cxl: Fix NULL pointer dereference on kernel contexts with no AFU interrupts

[Ian Munsie]

Excerpts from andrew.donnellan's message of 2016-06-30 15:15:02 +1000:
> On 30/06/16 15:00, Michael Ellerman wrote:
> > On Thu, 2016-06-30 at 08:28 +1000, Andrew Donnellan wrote:
> >> On 30/06/16 04:55, Ian Munsie wrote:
> >>>
> >>> From: Ian Munsie <imunsie at au1.ibm.com>
> >>>
> >>> If a kernel context is initialised and does not have any AFU interrupts
> >>> allocated it will cause a NULL pointer dereference when the context is
> >>> detached since the irq_names list will not have been initialised.
> >>>
> >>> Move the initialisation of the irq_names list into the cxl_context_init
> >>> routine so that it will be valid for the entire lifetime of the context
> >>> and will not cause a NULL pointer dereference.
> >>>
> >>> Signed-off-by: Ian Munsie <imunsie at au1.ibm.com>
> >
> >> As it's nice having your machine not crash on every shutdown...
> >
> > Fixes: ????
> 
> Ian can correct me if I'm wrong, but I suspect this doesn't affect 
> cxlflash (the only current user of the cxl kernel API) - this issue was 
> hit while working on CAPI support for mlx5.

Correct - no current user hits this bug, but the upcoming mlx5 support
does because of the way it uses interrupts.

-Ian