From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B0BAC329C6D; Mon, 20 Apr 2026 15:56:03 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776700563; cv=none; b=CRwEeqEXy/D+dt0pqD6AqEY+uaxRB2eLIVlXAFisWVjgKLZk84H2KIq+tI4xzYaQjeQgalHxXHntbB3uf2e4NKjLJCeC6+dHm3+tWU8NkdXC5PFzt7nPGriJJB4X0zpRjGHqQ3ZquzUod/jfPuTWn8n/ymLfn94nmtTI7/rl5Xk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776700563; c=relaxed/simple; bh=sBylf4tCef+eZxBoE//OD8hUoCjBBj4JK+t8JVfA7i0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=rRpd8phHnA8wj6jmoNcxOwa8ctbFvLEKfgmRnrye2UX15w0d50xUrxlqXRW9y9b+cApmwWEQNr1qVcW0Vw9Dj7RjWPHaAxjRPVc7u197cwV87Fcgy2nCUshbRBBU2FXbzkIXbHVC9dNKE4Y5jS5OyOLVHqzFGIBkseB2wc9qDXE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=2JotChEB; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="2JotChEB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 46EF7C2BCB4; Mon, 20 Apr 2026 15:56:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776700563; bh=sBylf4tCef+eZxBoE//OD8hUoCjBBj4JK+t8JVfA7i0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=2JotChEBr9c4cQspD4V4CE0ah1Drtm9tGECEo55rsbhQJtA4oxULH9ONyybeDSmNq h7q5VaQF+TJpfjfHLWSlHcO7V6N+CaqIuW3JTnSa/3Neq9lszXwfBX9D05A3EURplh 0Qhd1N2B61RVKyNnbcOTYBonXfXZLqeuzL08Q+D8= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+f2fbf7478a35a94c8b7c@syzkaller.appspotmail.com, Shardul Bankar , "Jason A. Donenfeld" , Jakub Kicinski Subject: [PATCH 6.19 213/220] wireguard: device: use exit_rtnl callback instead of manual rtnl_lock in pre_exit Date: Mon, 20 Apr 2026 17:42:34 +0200 Message-ID: <20260420153941.697027624@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260420153934.013228280@linuxfoundation.org> References: <20260420153934.013228280@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shardul Bankar commit 60a25ef8dacb3566b1a8c4de00572a498e2a3bf9 upstream. wg_netns_pre_exit() manually acquires rtnl_lock() inside the pernet .pre_exit callback. This causes a hung task when another thread holds rtnl_mutex - the cleanup_net workqueue (or the setup_net failure rollback path) blocks indefinitely in wg_netns_pre_exit() waiting to acquire the lock. Convert to .exit_rtnl, introduced in commit 7a60d91c690b ("net: Add ->exit_rtnl() hook to struct pernet_operations."), where the framework already holds RTNL and batches all callbacks under a single rtnl_lock()/rtnl_unlock() pair, eliminating the contention window. The rcu_assign_pointer(wg->creating_net, NULL) is safe to move from .pre_exit to .exit_rtnl (which runs after synchronize_rcu()) because all RCU readers of creating_net either use maybe_get_net() - which returns NULL for a dying namespace with zero refcount - or access net->user_ns which remains valid throughout the entire ops_undo_list sequence. Reported-by: syzbot+f2fbf7478a35a94c8b7c@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?id=cb64c22a492202ca929e18262fdb8cb89e635c70 Signed-off-by: Shardul Bankar [ Jason: added __net_exit and __read_mostly annotations that were missing. ] Fixes: 900575aa33a3 ("wireguard: device: avoid circular netns references") Cc: stable@vger.kernel.org Signed-off-by: Jason A. Donenfeld Link: https://patch.msgid.link/20260414153944.2742252-5-Jason@zx2c4.com Signed-off-by: Jakub Kicinski Signed-off-by: Greg Kroah-Hartman --- drivers/net/wireguard/device.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) --- a/drivers/net/wireguard/device.c +++ b/drivers/net/wireguard/device.c @@ -411,12 +411,11 @@ static struct rtnl_link_ops link_ops __r .newlink = wg_newlink, }; -static void wg_netns_pre_exit(struct net *net) +static void __net_exit wg_netns_exit_rtnl(struct net *net, struct list_head *dev_kill_list) { struct wg_device *wg; struct wg_peer *peer; - rtnl_lock(); list_for_each_entry(wg, &device_list, device_list) { if (rcu_access_pointer(wg->creating_net) == net) { pr_debug("%s: Creating namespace exiting\n", wg->dev->name); @@ -429,11 +428,10 @@ static void wg_netns_pre_exit(struct net mutex_unlock(&wg->device_update_lock); } } - rtnl_unlock(); } -static struct pernet_operations pernet_ops = { - .pre_exit = wg_netns_pre_exit +static struct pernet_operations pernet_ops __read_mostly = { + .exit_rtnl = wg_netns_exit_rtnl }; int __init wg_device_init(void)