[PATCH 4.14 132/222] libnvdimm, region: Fail badblocks listing for inactive regions

Greg Kroah-Hartman
2018-11-11T22:57:34Z

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

commit 5d394eee2c102453278d81d9a7cf94c80253486a upstream.

While experimenting with region driver loading the following backtrace
was triggered:

INFO: trying to register non-static key.
the code is fine but needs lockdep annotation.
turning off the locking correctness validator.
[..]
Call Trace:
dump_stack+0x85/0xcb
register_lock_class+0x571/0x580
? __lock_acquire+0x2ba/0x1310
? kernfs_seq_start+0x2a/0x80
__lock_acquire+0xd4/0x1310
? dev_attr_show+0x1c/0x50
? __lock_acquire+0x2ba/0x1310
? kernfs_seq_start+0x2a/0x80
? lock_acquire+0x9e/0x1a0
lock_acquire+0x9e/0x1a0
? dev_attr_show+0x1c/0x50
badblocks_show+0x70/0x190
? dev_attr_show+0x1c/0x50
dev_attr_show+0x1c/0x50

This results from a missing successful call to devm_init_badblocks()
from nd_region_probe(). Block attempts to show badblocks while the
region is not enabled.

Fixes: 6a6bef90425e ("libnvdimm: add mechanism to publish badblocks...")
Cc: <stable@vger.kernel.org>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/nvdimm/region_devs.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

--- a/drivers/nvdimm/region_devs.c
+++ b/drivers/nvdimm/region_devs.c
@@ -513,10 +513,17 @@ static ssize_t region_badblocks_show(str
struct device_attribute *attr, char *buf)
{
struct nd_region *nd_region = to_nd_region(dev);
+ ssize_t rc;

- return badblocks_show(&nd_region->bb, buf, 0);
-}
+ device_lock(dev);
+ if (dev->driver)
+ rc = badblocks_show(&nd_region->bb, buf, 0);
+ else
+ rc = -ENXIO;
+ device_unlock(dev);

+ return rc;
+}
static DEVICE_ATTR(badblocks, 0444, region_badblocks_show, NULL);

static ssize_t resource_show(struct device *dev,