[PATCH 4.10 044/129] iwlwifi: mvm: properly check for transport data in dump

[Greg Kroah-Hartman]

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

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

From: Johannes Berg <johannes.berg@xxxxxxxxx>

commit c2e27e16f2411155b906db201b7e478144034ffe upstream.

When copying from vmalloc'ed memory to the SG list, don't crash
if the transport didn't provide any data.

Fixes: 7e62a699aafb ("iwlwifi: mvm: use dev_coredumpsg()")
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Luca Coelho <luciano.coelho@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c |   11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

--- a/drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/fw-dbg.c
@@ -816,11 +816,12 @@ dump_trans_data:
 				     sg_nents(sg_dump_data),
 				     fw_error_dump->op_mode_ptr,
 				     fw_error_dump->op_mode_len, 0);
-		sg_pcopy_from_buffer(sg_dump_data,
-				     sg_nents(sg_dump_data),
-				     fw_error_dump->trans_ptr->data,
-				     fw_error_dump->trans_ptr->len,
-				     fw_error_dump->op_mode_len);
+		if (fw_error_dump->trans_ptr)
+			sg_pcopy_from_buffer(sg_dump_data,
+					     sg_nents(sg_dump_data),
+					     fw_error_dump->trans_ptr->data,
+					     fw_error_dump->trans_ptr->len,
+					     fw_error_dump->op_mode_len);
 		dev_coredumpsg(mvm->trans->dev, sg_dump_data, file_len,
 			       GFP_KERNEL);
 	}