Re: [PATCH net] net: fix memory leak in register_netdevice() on error path

[Toshiaki Makita]

On 2020/11/26 22:23, Yang Yingliang wrote:
...

Reported-by: Hulk Robot <hul...@huawei.com>
Signed-off-by: Yang Yingliang <yangyingli...@huawei.com>
---
  net/core/dev.c | 11 +++++++++++
  1 file changed, 11 insertions(+)

diff --git a/net/core/dev.c b/net/core/dev.c
index 82dc6b48e45f..907204395b64 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -10000,6 +10000,17 @@ int register_netdevice(struct net_device *dev)
        ret = notifier_to_errno(ret);
        if (ret) {
                rollback_registered(dev);
+               /*
+                * In common case, priv_destructor() will be

As per netdev-faq, the comment style should be

/* foobar blah blah blah
 * another line of text
 */

rather than

/*
 * foobar blah blah blah
 * another line of text
 */

+                * called in netdev_run_todo() after calling
+                * ndo_uninit() in rollback_registered().
+                * But in this case, priv_destructor() will
+                * never be called, then it causes memory
+                * leak, so we should call priv_destructor()
+                * here.
+                */
+               if (dev->priv_destructor)
+                       dev->priv_destructor(dev);

To be in line with netdev_run_todo(), I think priv_destructor() should be
called after "dev->reg_state = NETREG_UNREGISTERED".

Toshiaki Makita

                rcu_barrier();

dev->reg_state = NETREG_UNREGISTERED;