[PATCH] net-sysfs: Fix mem leak in netdev_register_kobject

[Yue Haibing]

From: YueHaibing <yuehaibing@xxxxxxxxxx>

syzkaller report this:
BUG: memory leak
unreferenced object 0xffff88837a71a500 (size 256):
  comm "syz-executor.2", pid 9770, jiffies 4297825125 (age 17.843s)
  hex dump (first 32 bytes):
    00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00  .....N..........
    ff ff ff ff ff ff ff ff 20 c0 ef 86 ff ff ff ff  ........ .......
  backtrace:
    [<00000000db12624b>] netdev_register_kobject+0x124/0x2e0 net/core/net-sysfs.c:1751
    [<00000000dc49a994>] register_netdevice+0xcc1/0x1270 net/core/dev.c:8516
    [<00000000e5f3fea0>] tun_set_iff drivers/net/tun.c:2649 [inline]
    [<00000000e5f3fea0>] __tun_chr_ioctl+0x2218/0x3d20 drivers/net/tun.c:2883
    [<000000001b8ac127>] vfs_ioctl fs/ioctl.c:46 [inline]
    [<000000001b8ac127>] do_vfs_ioctl+0x1a5/0x10e0 fs/ioctl.c:690
    [<0000000079b269f8>] ksys_ioctl+0x89/0xa0 fs/ioctl.c:705
    [<00000000de649beb>] __do_sys_ioctl fs/ioctl.c:712 [inline]
    [<00000000de649beb>] __se_sys_ioctl fs/ioctl.c:710 [inline]
    [<00000000de649beb>] __x64_sys_ioctl+0x74/0xb0 fs/ioctl.c:710
    [<000000007ebded1e>] do_syscall_64+0xc8/0x580 arch/x86/entry/common.c:290
    [<00000000db315d36>] entry_SYSCALL_64_after_hwframe+0x49/0xbe
    [<00000000115be9bb>] 0xffffffffffffffff

It should call kset_unregister to free 'dev->queues_kset'
in error path of register_queue_kobjects, otherwise will cause a mem leak.

Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Fixes: 1d24eb4815d1 ("xps: Transmit Packet Steering")
Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
---
 net/core/net-sysfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index 7c50611..bbeb606 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -1541,6 +1541,9 @@ static int register_queue_kobjects(struct net_device *dev)
 error:
 	netdev_queue_update_kobjects(dev, txq, 0);
 	net_rx_queue_update_kobjects(dev, rxq, 0);
+#ifdef CONFIG_SYSFS
+	kset_unregister(dev->queues_kset);
+#endif
 	return error;
 }
 
-- 
2.7.0