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

[Dan Williams]

On Tue, Apr 25, 2017 at 4:40 PM, Kani, Toshimitsu <toshi.kani@xxxxxxx> wrote:
> 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@xxxxxxx>
>> 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@xxxxxxx>
>> > Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
>> > Cc: Vishal Verma <vishal.l.verma@xxxxxxxxx>
>>
>>
>> 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.

Yes, I'll try to come up with something for nfit_test.

Thanks Toshi!