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From: Rongguang Wei <clementwei90@163.com>
To: netdev@vger.kernel.org
Cc: willemdebruijn.kernel@gmail.com, jasowangio@gmail.com,
	andrew+netdev@lunn.ch, davem@davemloft.net,
	Rongguang Wei <weirongguang@kylinos.cn>
Subject: [PATCH net v1] tun: fix inverted error check when re-attaching the filter
Date: Wed, 23 Sep 2026 10:56:53 +0800	[thread overview]
Message-ID: <20260923025653.59348-1-clementwei90@163.com> (raw)

From: Rongguang Wei <weirongguang@kylinos.cn>

tun_attach() return when sk_attach_filter() succeeds instead of when it
fails, so the queue is never published in tun->tfiles[] while TUNSETIFF
still reports success.

Invert the check; nothing is published at that point, so the attach can be
aborted cleanly.

Fixes: 54f968d6efdb ("tuntap: move socket to tun_file")
Signed-off-by: Rongguang Wei <weirongguang@kylinos.cn>
---
 drivers/net/tun.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 5a302709a68a..09720883b9a1 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -754,7 +754,7 @@ static int tun_attach(struct tun_struct *tun, struct file *file,
 		lock_sock(tfile->socket.sk);
 		err = sk_attach_filter(&tun->fprog, tfile->socket.sk);
 		release_sock(tfile->socket.sk);
-		if (!err)
+		if (err)
 			goto out;
 	}
 
-- 
2.25.1


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             reply	other threads:[~2026-09-23  2:57 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-23  2:56 Rongguang Wei [this message]
2026-09-24 17:59 ` [PATCH net v1] tun: fix inverted error check when re-attaching the filter netdev-bot+sashiko
2026-09-25 17:15   ` Willem de Bruijn
2026-09-28  2:02     ` Rongguang Wei

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