netdev - [PATCH v2] hv_netvsc: fix a possible NULL pointer dereference in netvsc_get_ethtool

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Message-Id: <20190312050149.3032-1-kjlu@umn.edu>
Date:   Tue, 12 Mar 2019 00:01:49 -0500
From:   Kangjie Lu <kjlu@....edu>
To:     kjlu@....edu
Cc:     pakki001@....edu, "K. Y. Srinivasan" <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Sasha Levin <sashal@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        linux-hyperv@...r.kernel.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v2] hv_netvsc: fix a possible NULL pointer dereference in netvsc_get_ethtool_stats()

In case kvmalloc_array fails, we should stop using it to avoid
NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu@....edu>
---
 drivers/net/hyperv/netvsc_drv.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index cf4897043e83..4b3a03029fe8 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -1426,6 +1426,9 @@ static void netvsc_get_ethtool_stats(struct net_device *dev,
 	pcpu_sum = kvmalloc_array(num_possible_cpus(),
 				  sizeof(struct netvsc_ethtool_pcpu_stats),
 				  GFP_KERNEL);
+	if (!pcpu_sum)
+		return;
+
 	netvsc_get_pcpu_stats(dev, pcpu_sum);
 	for_each_present_cpu(cpu) {
 		struct netvsc_ethtool_pcpu_stats *this_sum = &pcpu_sum[cpu];
-- 
2.17.1