[PATCH 4.13 24/52] libnvdimm, btt: check memory allocation failure

4.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Christophe Jaillet <redacted>

commit ed36b4dba54a421ce5551638f6a9790b2c2116b1 upstream.

Check memory allocation failures and return -ENOMEM in such cases, as
already done few lines below for another memory allocation.

This avoids NULL pointers dereference.

Fixes: 14e494542636 ("libnvdimm, btt: BTT updates for UEFI 2.7 format")
Signed-off-by: Christophe JAILLET <redacted>
Reviewed-by: Vishal Verma <vishal.l.verma@intel.com>
Signed-off-by: Dan Williams <redacted>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/nvdimm/btt.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c

@@ -1429,6 +1429,8 @@ int nvdimm_namespace_attach_btt(struct n
 	}
 
 	btt_sb = devm_kzalloc(&nd_btt->dev, sizeof(*btt_sb), GFP_KERNEL);
+	if (!btt_sb)
+		return -ENOMEM;
 
 	/*
 	 * If this returns < 0, that is ok as it just means there wasn't