netdev - [PATCH] net: macvlan: fix memory leaks of macvlan_common

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Message-Id: <20221109090735.690500-1-nashuiliang@gmail.com>
Date:   Wed,  9 Nov 2022 17:07:34 +0800
From:   Chuang Wang <nashuiliang@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Chuang Wang <nashuiliang@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>, Gao Feng <fgao@...ai8.com>,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] net: macvlan: fix memory leaks of macvlan_common_newlink

kmemleak reports memory leaks in macvlan_common_newlink, as follows:

 ip link add link eth0 name .. type macvlan mode source macaddr add
 <MAC-ADDR>

kmemleak reports:

unreferenced object 0xffff8880109bb140 (size 64):
  comm "ip", pid 284, jiffies 4294986150 (age 430.108s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 b8 aa 5a 12 80 88 ff ff  ..........Z.....
    80 1b fa 0d 80 88 ff ff 1e ff ac af c7 c1 6b 6b  ..............kk
  backtrace:
    [<ffffffff813e06a7>] kmem_cache_alloc_trace+0x1c7/0x300
    [<ffffffff81b66025>] macvlan_hash_add_source+0x45/0xc0
    [<ffffffff81b66a67>] macvlan_changelink_sources+0xd7/0x170
    [<ffffffff81b6775c>] macvlan_common_newlink+0x38c/0x5a0
    [<ffffffff81b6797e>] macvlan_newlink+0xe/0x20
    [<ffffffff81d97f8f>] __rtnl_newlink+0x7af/0xa50
    [<ffffffff81d98278>] rtnl_newlink+0x48/0x70
    ...

In the scenario where the macvlan mode is configured as 'source',
macvlan_changelink_sources() will be execured to reconfigure list of
remote source mac addresses, at the same time, if register_netdevice()
return an error, the resource generated by macvlan_changelink_sources()
is not cleaned up.

Using this patch, in the case of an error, it will execute
macvlan_flush_sources() to ensure that the resource is cleaned up.

Fixes: aa5fd0fb7748 ("driver: macvlan: Destroy new macvlan port if macvlan_common_newlink failed.")
Signed-off-by: Chuang Wang <nashuiliang@...il.com>
---
 drivers/net/macvlan.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/macvlan.c b/drivers/net/macvlan.c
index c58fea63be7d..28f9f917ff54 100644
--- a/drivers/net/macvlan.c
+++ b/drivers/net/macvlan.c
@@ -1533,8 +1533,10 @@ int macvlan_common_newlink(struct net *src_net, struct net_device *dev,
 	/* the macvlan port may be freed by macvlan_uninit when fail to register.
 	 * so we destroy the macvlan port only when it's valid.
 	 */
-	if (create && macvlan_port_get_rtnl(lowerdev))
+	if (create && macvlan_port_get_rtnl(lowerdev)) {
+		macvlan_flush_sources(port, vlan);
 		macvlan_port_destroy(port->dev);
+	}
 	return err;
 }
 EXPORT_SYMBOL_GPL(macvlan_common_newlink);
-- 
2.37.2