netdev - [PATCH net 3/4] net-sysfs: check device is present when showing testing

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Message-Id: <2a96f450e4150e9b8c39fb000d82c17987c5bbc5.1721784184.git.jamie.bainbridge@gmail.com>
Date: Wed, 24 Jul 2024 11:46:52 +1000
From: Jamie Bainbridge <jamie.bainbridge@...il.com>
To: netdev@...r.kernel.org,
	"David S. Miller" <davem@...emloft.net>,
	Eric Dumazet <edumazet@...gle.com>,
	Jakub Kicinski <kuba@...nel.org>,
	Paolo Abeni <pabeni@...hat.com>
Cc: Jamie Bainbridge <jamie.bainbridge@...il.com>,
	Andrew Lunn <andrew@...n.ch>,
	Florian Fainelli <f.fainelli@...il.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH net 3/4] net-sysfs: check device is present when showing testing

A sysfs reader can race with a device reset or removal.

This was fixed for speed_show with commit 4224cfd7fb65 ("net-sysfs: add
check for netdevice being present to speed_show") so add the same check
to testing_show.

Fixes: db30a57779b1 ("net: Add testing sysfs attribute")

Signed-off-by: Jamie Bainbridge <jamie.bainbridge@...il.com>
---
 net/core/net-sysfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 3a539a2bd4d11c5f5d7b6f15a23d61439f178c3b..17927832a4fbb56d3e1dfbed29c567d70ab944be 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -291,7 +291,7 @@ static ssize_t testing_show(struct device *dev,
 {
 	struct net_device *netdev = to_net_dev(dev);
 
-	if (netif_running(netdev))
+	if (netif_running(netdev) && netif_device_present(netdev))
 		return sysfs_emit(buf, fmt_dec, !!netif_testing(netdev));
 
 	return -EINVAL;
-- 
2.39.2