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 AF581354AF8 for ; Mon, 20 Apr 2026 15:03:40 +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=1776697420; cv=none; b=LdhKSOuFBfKvv2N8YqwOz6o5jZXE4Rb3ql2eOUkE0U2x9m2hOOVIXtTS5awLfVLcVDnsr/vPB8tp59UzaYx8vbmKKlb52US78UsSsrPED9B9fMmiYujosBUDzodFgLT7Lh84LfNXdX7UNCFWSaNhyjpANlA5zzt1a+EmepPjljg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776697420; c=relaxed/simple; bh=KhoGTWDxyIpl+1txAY4njNXk2F0MSc3riVvTzNrEx1k=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=Y+r3rZzbA+0FcTe48LPqbH+iChE4/fa2IZW4JDIHoHzFz5jqZRlhZeQcT41pegHKeGzoRzmpZYyCILtxYDfXi8dyDMnEjSo+cygzeEdJENCvN2Mw2Gkq/zR1j+4Tc8QgQ/K6uGuWTPocVHtEwvWynLUO771vzFoWSBUWUS0Fo7s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ORxUbam0; 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="ORxUbam0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 476DBC19425; Mon, 20 Apr 2026 15:03:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776697420; bh=KhoGTWDxyIpl+1txAY4njNXk2F0MSc3riVvTzNrEx1k=; h=Subject:To:Cc:From:Date:From; b=ORxUbam0Tsq5ca4P8FFKnoaHE1My0lMWAVGUpLtafpTxEKCOE9faK0RDErqAqHZ0j IeZAQ6hPWpQoVaBCxIPgyEgY2PP0mAYb3TUKDxaE4cqc1R5aQpD50VfhB4k+GKEBf+ DDLhzxJ2xOd8S2ccNceQUqxyztrqyokTncBDDEL8= Subject: FAILED: patch "[PATCH] wireguard: device: use exit_rtnl callback instead of manual" failed to apply to 5.15-stable tree To: shardul.b@mpiricsoftware.com,Jason@zx2c4.com,kuba@kernel.org Cc: From: Date: Mon, 20 Apr 2026 17:03:32 +0200 Message-ID: <2026042032-atypical-thumb-717d@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 60a25ef8dacb3566b1a8c4de00572a498e2a3bf9 # git commit -s git send-email --to '' --in-reply-to '2026042032-atypical-thumb-717d@gregkh' --subject-prefix 'PATCH 5.15.y' HEAD^.. Possible dependencies: thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 60a25ef8dacb3566b1a8c4de00572a498e2a3bf9 Mon Sep 17 00:00:00 2001 From: Shardul Bankar Date: Tue, 14 Apr 2026 17:39:44 +0200 Subject: [PATCH] wireguard: device: use exit_rtnl callback instead of manual rtnl_lock in pre_exit 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 diff --git a/drivers/net/wireguard/device.c b/drivers/net/wireguard/device.c index 46a71ec36af8..67b07ee2d660 100644 --- a/drivers/net/wireguard/device.c +++ b/drivers/net/wireguard/device.c @@ -411,12 +411,11 @@ 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); @@ -429,11 +428,10 @@ 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)