[PATCH 6.1 04/71] smb/client: avoid dereferencing rdata=NULL in smb2_new_read_req()

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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

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

From: Stefan Metzmacher <metze@samba.org>

commit c724b2ab6a46435b4e7d58ad2fbbdb7a318823cf upstream.

This happens when called from SMB2_read() while using rdma
and reaching the rdma_readwrite_threshold.

Cc: stable@vger.kernel.org
Fixes: a6559cc1d35d ("cifs: split out smb3_use_rdma_offload() helper")
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Stefan Metzmacher <metze@samba.org>
Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 fs/smb/client/smb2pdu.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/fs/smb/client/smb2pdu.c
+++ b/fs/smb/client/smb2pdu.c
@@ -4184,7 +4184,7 @@ smb2_new_read_req(void **buf, unsigned i
 	 * If we want to do a RDMA write, fill in and append
 	 * smbd_buffer_descriptor_v1 to the end of read request
 	 */
-	if (smb3_use_rdma_offload(io_parms)) {
+	if (rdata && smb3_use_rdma_offload(io_parms)) {
 		struct smbd_buffer_descriptor_v1 *v1;
 		bool need_invalidate = server->dialect == SMB30_PROT_ID;