From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 CB5C15B5AB; Sat, 17 Oct 2026 16:14:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792253688; cv=none; b=fNc0aybn6ASHR+prQwyIgdYzbph0Mg/x4+wawNm35aRXiGBVtbICBh63uZoPjyCmKj87ioXHhkrQK73YrrAyJl6tL0Zu44DBQMUsom7gHxOAT3Qd6vMVXy/dKWaz7ujt5ha9zfJKb1gpUbj0AH967jgYTi4Me7lSzZWS/vn4So0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792253688; c=relaxed/simple; bh=f54oxjWJ7n5y5iqxLgAHWA9el5/aNthMaTg8m0rbFps=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=OKD9ItI/jnqGH/6Ue1WmPaIuMVoSxdET257Hqx7GHxZYREZMnXz1MVJiqh0p3wOp3PAMIJmJNnt6fQ3YN//xe00i9Dl+qsgRtCk77os/YAF74KLH2ocQT7cz5MxxXH4A/Vz1xq4BqS6sdgOD2gyww67kOKkyUXwrRpJsHeuvxpI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=YF34pxuA; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="YF34pxuA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2B66E1F000C4; Sat, 17 Oct 2026 16:14:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792253686; bh=0b+Zqx76zxF/FUxknlugAY85P8kmlzDWuC9kwgMuSu0=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=YF34pxuA2GvJ51oe+rvnXBFobsYdL3NrhC4XsihkF4NBlmPkzGNyPpb2wIQ7tsush 1CJLdaoeVKf4i/4tmdO2rVQme5Cf0h7he7dzlCWvV5RGVLdzhD3BHjSAUqTmF7Iiy5 zyJ+K8Pfo/BBmu6iUvE37RY1+mZywvg+FXJAQFOg= 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 , Sasha Levin Subject: [PATCH 6.12 198/869] wireguard: device: use exit_rtnl callback instead of manual rtnl_lock in pre_exit Date: Sat, 17 Oct 2026 17:50:39 +0200 Message-ID: <20261017160042.134440648@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261017160036.979869304@linuxfoundation.org> References: <20261017160036.979869304@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 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shardul Bankar [ Upstream commit 60a25ef8dacb3566b1a8c4de00572a498e2a3bf9 ] 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: Sasha Levin --- drivers/net/wireguard/device.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/net/wireguard/device.c b/drivers/net/wireguard/device.c index 45e9b908dbfb0..055ea38771568 100644 --- a/drivers/net/wireguard/device.c +++ b/drivers/net/wireguard/device.c @@ -406,12 +406,11 @@ static struct rtnl_link_ops link_ops __read_mostly = { .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); @@ -424,11 +423,10 @@ static void wg_netns_pre_exit(struct net *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) -- 2.53.0