Re: [PATCH] pmem: fix a NULL pointer BUG in nd_pmem_notify

["Kani, Toshimitsu" <toshi.kani@hpe.com>]

On Tue, 2017-04-25 at 16:07 -0700, Dan Williams wrote:
> On Tue, Apr 25, 2017 at 4:04 PM, Toshi Kani <toshi.kani@hpe.com>
> wrote:
> > The following BUG was observed when nd_pmem_notify() was called
> > for a BTT device.  The use of a pmem_device pointer is not valid
> > with BTT.
> > 
> >  BUG: unable to handle kernel NULL pointer dereference at
> > 0000000000000030
> >  IP: nd_pmem_notify+0x30/0xf0 [nd_pmem]
> >  Call Trace:
> >   nd_device_notify+0x40/0x50
> >   child_notify+0x10/0x20
> >   device_for_each_child+0x50/0x90
> >   nd_region_notify+0x20/0x30
> >   nd_device_notify+0x40/0x50
> >   nvdimm_region_notify+0x27/0x30
> >   acpi_nfit_scrub+0x341/0x590 [nfit]
> >   process_one_work+0x197/0x450
> >   worker_thread+0x4e/0x4a0
> >   kthread+0x109/0x140
> > 
> > Fix nd_pmem_notify() by setting nd_region and badblocks pointers
> > properly for BTT.
> > 
> > Signed-off-by: Toshi Kani <toshi.kani@hpe.com>
> > Cc: Dan Williams <dan.j.williams@intel.com>
> > Cc: Vishal Verma <vishal.l.verma@intel.com>
> 
> 
> Hi Toshi, how did you trigger this? I'd like to get your test into
> the regression suite.

Hi Dan,

I injected an error and started an ARS scan.  Unfortunately, my test
steps need to run on our platforms.  I think these error injection
features can be emulated, though.

Thanks,
-Toshi