2017-04-25 23:04:51

by Kani, Toshimitsu

[permalink] [raw]
Subject: [PATCH] pmem: fix a NULL pointer BUG in nd_pmem_notify

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 <[email protected]>
Cc: Dan Williams <[email protected]>
Cc: Vishal Verma <[email protected]>
---
drivers/nvdimm/pmem.c | 37 +++++++++++++++++++++++++------------
1 file changed, 25 insertions(+), 12 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 5b536be..0fc1826 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -388,12 +388,12 @@ static void nd_pmem_shutdown(struct device *dev)

static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
{
- struct pmem_device *pmem = dev_get_drvdata(dev);
- struct nd_region *nd_region = to_region(pmem);
+ struct nd_region *nd_region;
resource_size_t offset = 0, end_trunc = 0;
struct nd_namespace_common *ndns;
struct nd_namespace_io *nsio;
struct resource res;
+ struct badblocks *bb;

if (event != NVDIMM_REVALIDATE_POISON)
return;
@@ -402,20 +402,33 @@ static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
struct nd_btt *nd_btt = to_nd_btt(dev);

ndns = nd_btt->ndns;
- } else if (is_nd_pfn(dev)) {
- struct nd_pfn *nd_pfn = to_nd_pfn(dev);
- struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
+ nd_region = to_nd_region(ndns->dev.parent);
+ nsio = to_nd_namespace_io(&ndns->dev);
+ bb = &nsio->bb;
+ } else {
+ struct pmem_device *pmem = dev_get_drvdata(dev);

- ndns = nd_pfn->ndns;
- offset = pmem->data_offset + __le32_to_cpu(pfn_sb->start_pad);
- end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
- } else
- ndns = to_ndns(dev);
+ nd_region = to_region(pmem);
+ bb = &pmem->bb;
+
+ if (is_nd_pfn(dev)) {
+ struct nd_pfn *nd_pfn = to_nd_pfn(dev);
+ struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
+
+ ndns = nd_pfn->ndns;
+ offset = pmem->data_offset +
+ __le32_to_cpu(pfn_sb->start_pad);
+ end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
+ } else {
+ ndns = to_ndns(dev);
+ }
+
+ nsio = to_nd_namespace_io(&ndns->dev);
+ }

- nsio = to_nd_namespace_io(&ndns->dev);
res.start = nsio->res.start + offset;
res.end = nsio->res.end - end_trunc;
- nvdimm_badblocks_populate(nd_region, &pmem->bb, &res);
+ nvdimm_badblocks_populate(nd_region, bb, &res);
}

MODULE_ALIAS("pmem");


2017-04-25 23:07:28

by Dan Williams

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

On Tue, Apr 25, 2017 at 4:04 PM, Toshi Kani <[email protected]> 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 <[email protected]>
> Cc: Dan Williams <[email protected]>
> Cc: Vishal Verma <[email protected]>


Hi Toshi, how did you trigger this? I'd like to get your test into the
regression suite.


> ---
> drivers/nvdimm/pmem.c | 37 +++++++++++++++++++++++++------------
> 1 file changed, 25 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 5b536be..0fc1826 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -388,12 +388,12 @@ static void nd_pmem_shutdown(struct device *dev)
>
> static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
> {
> - struct pmem_device *pmem = dev_get_drvdata(dev);
> - struct nd_region *nd_region = to_region(pmem);
> + struct nd_region *nd_region;
> resource_size_t offset = 0, end_trunc = 0;
> struct nd_namespace_common *ndns;
> struct nd_namespace_io *nsio;
> struct resource res;
> + struct badblocks *bb;
>
> if (event != NVDIMM_REVALIDATE_POISON)
> return;
> @@ -402,20 +402,33 @@ static void nd_pmem_notify(struct device *dev, enum nvdimm_event event)
> struct nd_btt *nd_btt = to_nd_btt(dev);
>
> ndns = nd_btt->ndns;
> - } else if (is_nd_pfn(dev)) {
> - struct nd_pfn *nd_pfn = to_nd_pfn(dev);
> - struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
> + nd_region = to_nd_region(ndns->dev.parent);
> + nsio = to_nd_namespace_io(&ndns->dev);
> + bb = &nsio->bb;
> + } else {
> + struct pmem_device *pmem = dev_get_drvdata(dev);
>
> - ndns = nd_pfn->ndns;
> - offset = pmem->data_offset + __le32_to_cpu(pfn_sb->start_pad);
> - end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
> - } else
> - ndns = to_ndns(dev);
> + nd_region = to_region(pmem);
> + bb = &pmem->bb;
> +
> + if (is_nd_pfn(dev)) {
> + struct nd_pfn *nd_pfn = to_nd_pfn(dev);
> + struct nd_pfn_sb *pfn_sb = nd_pfn->pfn_sb;
> +
> + ndns = nd_pfn->ndns;
> + offset = pmem->data_offset +
> + __le32_to_cpu(pfn_sb->start_pad);
> + end_trunc = __le32_to_cpu(pfn_sb->end_trunc);
> + } else {
> + ndns = to_ndns(dev);
> + }
> +
> + nsio = to_nd_namespace_io(&ndns->dev);
> + }
>
> - nsio = to_nd_namespace_io(&ndns->dev);
> res.start = nsio->res.start + offset;
> res.end = nsio->res.end - end_trunc;
> - nvdimm_badblocks_populate(nd_region, &pmem->bb, &res);
> + nvdimm_badblocks_populate(nd_region, bb, &res);
> }
>
> MODULE_ALIAS("pmem");

2017-04-25 23:41:50

by Kani, Toshimitsu

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

On Tue, 2017-04-25 at 16:07 -0700, Dan Williams wrote:
> On Tue, Apr 25, 2017 at 4:04 PM, Toshi Kani <[email protected]>
> 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 <[email protected]>
> > Cc: Dan Williams <[email protected]>
> > Cc: Vishal Verma <[email protected]>
>
>
> 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

2017-04-26 14:05:30

by Dan Williams

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

On Tue, Apr 25, 2017 at 4:40 PM, Kani, Toshimitsu <[email protected]> wrote:
> On Tue, 2017-04-25 at 16:07 -0700, Dan Williams wrote:
>> On Tue, Apr 25, 2017 at 4:04 PM, Toshi Kani <[email protected]>
>> 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 <[email protected]>
>> > Cc: Dan Williams <[email protected]>
>> > Cc: Vishal Verma <[email protected]>
>>
>>
>> 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!