Thread (11 messages) 11 messages, 4 authors, 2017-05-03

Re: [PATCH net v3] driver: veth: Fix one possbile memleak when fail to register_netdevice

From: Xin Long <lucien.xin@gmail.com>
Date: 2017-05-02 16:59:20

On Tue, May 2, 2017 at 7:03 PM, Gao Feng [off-list ref] wrote:
quoted
From: Xin Long [mailto:lucien.xin@gmail.com]
Sent: Tuesday, May 2, 2017 3:56 PM
On Sat, Apr 29, 2017 at 11:51 AM,  [off-list ref] wrote:
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From: Gao Feng <redacted>
[...]
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-static void veth_dev_free(struct net_device *dev)
+static void veth_destructor_free(struct net_device *dev)
 {
        free_percpu(dev->vstats);
+}
not sure why you needed to add this function.
to use free_percpu() directly may be clearer.
Because both of ndo_uninit and destructor need to perform same free statements.
It is good at maintain the codes with the common function.
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+
+static void veth_dev_uninit(struct net_device *dev) {
call free_percpu() here, no need to check dev->reg_state.
free_percpu will just return if dev->vstats is NULL.
It would break the original design if don't check the reg_state.
The original logic is that free the resources in the destructor, not in ndo_init.
I got what you're doing now, can you pls try to fix this with:
--- a/drivers/net/veth.c
+++ b/drivers/net/veth.c
@@ -219,10 +219,9 @@ static int veth_dev_init(struct net_device *dev)
        return 0;
 }

-static void veth_dev_free(struct net_device *dev)
+static void veth_dev_uninit(struct net_device *dev)
 {
        free_percpu(dev->vstats);
-       free_netdev(dev);
 }

 #ifdef CONFIG_NET_POLL_CONTROLLER
@@ -279,6 +278,7 @@ static void veth_set_rx_headroom(struct net_device
*dev, int new_hr)

 static const struct net_device_ops veth_netdev_ops = {
        .ndo_init            = veth_dev_init,
+       .ndo_uninit          = veth_dev_uninit,
        .ndo_open            = veth_open,
        .ndo_stop            = veth_close,
        .ndo_start_xmit      = veth_xmit,
@@ -317,7 +317,7 @@ static void veth_setup(struct net_device *dev)
                               NETIF_F_HW_VLAN_STAG_TX |
                               NETIF_F_HW_VLAN_CTAG_RX |
                               NETIF_F_HW_VLAN_STAG_RX);
-       dev->destructor = veth_dev_free;
+       dev->destructor = free_netdev;
        dev->max_mtu = ETH_MAX_MTU;

        dev->hw_features = VETH_FEATURES;

just as what other virtual nic drivers do (vxlan, geneve, macsec, bridge ....)
BTW, because I send multiple patches too fast today, the email server blocks my account.
So I have to reply you with a different email account. Sorry.

Best Regards
Feng
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[...]
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