netdev - [PATCH v1 net 2/2] geneve: Suppress list corruption splat in geneve_destroy

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Message-ID: <20250217203705.40342-3-kuniyu@amazon.com>
Date: Mon, 17 Feb 2025 12:37:05 -0800
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: Andrew Lunn <andrew+netdev@...n.ch>, "David S. Miller"
	<davem@...emloft.net>, Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski
	<kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
CC: Brad Spengler <spender@...ecurity.net>, Kuniyuki Iwashima
	<kuniyu@...zon.com>, Kuniyuki Iwashima <kuni1840@...il.com>,
	<netdev@...r.kernel.org>
Subject: [PATCH v1 net 2/2] geneve: Suppress list corruption splat in geneve_destroy_tunnels().

As explained in the previous patch, iterating for_each_netdev() and
gn->geneve_list during ->exit_batch_rtnl() could trigger ->dellink()
twice for the same device.

If CONFIG_DEBUG_LIST is enabled, we will see a list_del() corruption
splat in the 2nd call of geneve_dellink().

Let's remove for_each_netdev() in geneve_destroy_tunnels() and delegate
that part to default_device_exit_batch().

Fixes: 9593172d93b9 ("geneve: Fix use-after-free in geneve_find_dev().")
Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
 drivers/net/geneve.c | 7 -------
 1 file changed, 7 deletions(-)

diff --git a/drivers/net/geneve.c b/drivers/net/geneve.c
index a1f674539965..dbb3960126ee 100644
--- a/drivers/net/geneve.c
+++ b/drivers/net/geneve.c
@@ -1902,14 +1902,7 @@ static void geneve_destroy_tunnels(struct net *net, struct list_head *head)
 {
 	struct geneve_net *gn = net_generic(net, geneve_net_id);
 	struct geneve_dev *geneve, *next;
-	struct net_device *dev, *aux;
 
-	/* gather any geneve devices that were moved into this ns */
-	for_each_netdev_safe(net, dev, aux)
-		if (dev->rtnl_link_ops == &geneve_link_ops)
-			geneve_dellink(dev, head);
-
-	/* now gather any other geneve devices that were created in this ns */
 	list_for_each_entry_safe(geneve, next, &gn->geneve_list, next)
 		geneve_dellink(geneve->dev, head);
 }
-- 
2.39.5 (Apple Git-154)