[PATCH 4.4 092/137] libnvdimm: fix namespace object confusion in is_uuid_busy()

Greg Kroah-Hartman
2016-02-24T04:14:40Z

From: Dan Williams <dan.j.williams@intel.com>

commit e07ecd76d4db7bda1e9495395b2110a3fe28845a upstream.

When btt devices were re-worked to be child devices of regions this
routine was overlooked. It mistakenly attempts to_nd_namespace_pmem()
or to_nd_namespace_blk() conversions on btt and pfn devices. By luck to
date we have happened to be hitting valid memory leading to a uuid
miscompare, but a recent change to struct nd_namespace_common causes:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000001
IP: [<ffffffff814610dc>] memcmp+0xc/0x40
[..]
Call Trace:
[<ffffffffa0028631>] is_uuid_busy+0xc1/0x2a0 [libnvdimm]
[<ffffffffa0028570>] ? to_nd_blk_region+0x50/0x50 [libnvdimm]
[<ffffffff8158c9c0>] device_for_each_child+0x50/0x90

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/nvdimm/namespace_devs.c | 53 +++++++++++++++++++++++++++++++++++++
drivers/nvdimm/region_devs.c | 56 ----------------------------------------
2 files changed, 53 insertions(+), 56 deletions(-)

--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -77,6 +77,59 @@ static bool is_namespace_io(struct devic
return dev ? dev->type == &namespace_io_device_type : false;
}

+static int is_uuid_busy(struct device *dev, void *data)
+{
+ u8 *uuid1 = data, *uuid2 = NULL;
+
+ if (is_namespace_pmem(dev)) {
+ struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
+
+ uuid2 = nspm->uuid;
+ } else if (is_namespace_blk(dev)) {
+ struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);
+
+ uuid2 = nsblk->uuid;
+ } else if (is_nd_btt(dev)) {
+ struct nd_btt *nd_btt = to_nd_btt(dev);
+
+ uuid2 = nd_btt->uuid;
+ } else if (is_nd_pfn(dev)) {
+ struct nd_pfn *nd_pfn = to_nd_pfn(dev);
+
+ uuid2 = nd_pfn->uuid;
+ }
+
+ if (uuid2 && memcmp(uuid1, uuid2, NSLABEL_UUID_LEN) == 0)
+ return -EBUSY;
+
+ return 0;
+}
+
+static int is_namespace_uuid_busy(struct device *dev, void *data)
+{
+ if (is_nd_pmem(dev) || is_nd_blk(dev))
+ return device_for_each_child(dev, data, is_uuid_busy);
+ return 0;
+}
+
+/**
+ * nd_is_uuid_unique - verify that no other namespace has @uuid
+ * @dev: any device on a nvdimm_bus
+ * @uuid: uuid to check
+ */
+bool nd_is_uuid_unique(struct device *dev, u8 *uuid)
+{
+ struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
+
+ if (!nvdimm_bus)
+ return false;
+ WARN_ON_ONCE(!is_nvdimm_bus_locked(&nvdimm_bus->dev));
+ if (device_for_each_child(&nvdimm_bus->dev, uuid,
+ is_namespace_uuid_busy) != 0)
+ return false;
+ return true;
+}
+
bool pmem_should_map_pages(struct device *dev)
{
struct nd_region *nd_region = to_nd_region(dev->parent);
--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -134,62 +134,6 @@ int nd_region_to_nstype(struct nd_region
}
EXPORT_SYMBOL(nd_region_to_nstype);

-static int is_uuid_busy(struct device *dev, void *data)
-{
- struct nd_region *nd_region = to_nd_region(dev->parent);
- u8 *uuid = data;
-
- switch (nd_region_to_nstype(nd_region)) {
- case ND_DEVICE_NAMESPACE_PMEM: {
- struct nd_namespace_pmem *nspm = to_nd_namespace_pmem(dev);
-
- if (!nspm->uuid)
- break;
- if (memcmp(uuid, nspm->uuid, NSLABEL_UUID_LEN) == 0)
- return -EBUSY;
- break;
- }
- case ND_DEVICE_NAMESPACE_BLK: {
- struct nd_namespace_blk *nsblk = to_nd_namespace_blk(dev);
-
- if (!nsblk->uuid)
- break;
- if (memcmp(uuid, nsblk->uuid, NSLABEL_UUID_LEN) == 0)
- return -EBUSY;
- break;
- }
- default:
- break;
- }
-
- return 0;
-}
-
-static int is_namespace_uuid_busy(struct device *dev, void *data)
-{
- if (is_nd_pmem(dev) || is_nd_blk(dev))
- return device_for_each_child(dev, data, is_uuid_busy);
- return 0;
-}
-
-/**
- * nd_is_uuid_unique - verify that no other namespace has @uuid
- * @dev: any device on a nvdimm_bus
- * @uuid: uuid to check
- */
-bool nd_is_uuid_unique(struct device *dev, u8 *uuid)
-{
- struct nvdimm_bus *nvdimm_bus = walk_to_nvdimm_bus(dev);
-
- if (!nvdimm_bus)
- return false;
- WARN_ON_ONCE(!is_nvdimm_bus_locked(&nvdimm_bus->dev));
- if (device_for_each_child(&nvdimm_bus->dev, uuid,
- is_namespace_uuid_busy) != 0)
- return false;
- return true;
-}
-
static ssize_t size_show(struct device *dev,
struct device_attribute *attr, char *buf)
{