From 4428217941af05472531f15b8e488998d02d7255 Mon Sep 17 00:00:00 2001
From: Jouni Hogander <jouni.hogander@unikie.com>
Date: Tue, 17 Dec 2019 13:46:34 +0200
Subject: [PATCH 3/3] net-sysfs: Call dev_hold always in rx_queue_add_kobject
Git-commit: ddd9b5e3e765d8ed5a35786a6cb00111713fe161
Patch-mainline: v5.5-rc3
References: git-fixes
Dev_hold has to be called always in rx_queue_add_kobject.
Otherwise usage count drops below 0 in case of failure in
kobject_init_and_add.
Fixes: b8eb718348b8 ("net-sysfs: Fix reference count leak in rx|netdev_queue_add_kobject")
Reported-by: syzbot <syzbot+30209ea299c09d8785c9@syzkaller.appspotmail.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Miller <davem@davemloft.net>
Cc: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Jouni Hogander <jouni.hogander@unikie.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Denis Kirjanov <denis.kirjanov@suse.com>
---
net/core/net-sysfs.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index e2e9a04d6db0..cc371513b16f 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -886,14 +886,17 @@ static int rx_queue_add_kobject(struct net_device *dev, int index)
struct kobject *kobj = &queue->kobj;
int error = 0;
+ /* Kobject_put later will trigger rx_queue_release call which
+ * decreases dev refcount: Take that reference here
+ */
+ dev_hold(queue->dev);
+
kobj->kset = dev->queues_kset;
error = kobject_init_and_add(kobj, &rx_queue_ktype, NULL,
"rx-%u", index);
if (error)
goto err;
- dev_hold(queue->dev);
-
if (dev->sysfs_rx_queue_group) {
error = sysfs_create_group(kobj, dev->sysfs_rx_queue_group);
if (error)
--
2.16.4