From 4e2d9fc4d8119fdd536df15cc538002a7d7a0e75 Mon Sep 17 00:00:00 2001
From: Mark Zhang <markz@mellanox.com>
Date: Wed, 11 Sep 2019 11:12:43 +0300
Subject: [PATCH] rdma: Check comm string before print in print_comm()

Broken kernels (not-upstream) can provide wrong empty "comm" field.
It causes to segfault while printing in JSON format.

Fixes: 8ecac46a60ff ("rdma: Add QP resource tracking information")
Signed-off-by: Mark Zhang <markz@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 rdma/res.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/rdma/res.c b/rdma/res.c
index ef863f14..c5e8ba1d 100644
--- a/rdma/res.c
+++ b/rdma/res.c
@@ -159,6 +159,9 @@ void print_comm(struct rd *rd, const char *str, struct nlattr **nla_line)
 {
 	char tmp[18];
 
+	if (!str)
+		return;
+
 	if (rd->json_output) {
 		/* Don't beatify output in JSON format */
 		jsonw_string_field(rd->jw, "comm", str);