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 5B9A22E3AF1; Sun, 7 Jun 2026 10:20:33 +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=1780827634; cv=none; b=ASBZ3NBT+xARKxvcgzBFlVTBVKxh1ZfuuIds88iHf0/OJoGyuWfVGh2/e0bRfsX5ALaOfOlWmyjb+KSMj39yhT7Ex6MzC/r8bcALTyPZsxIK7raSwMab7Yw6JPVZX+JJjCJBipSM6tdt8aD2mZd6pPYO6Cbd6+G8u/7Iyl6hTI8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780827634; c=relaxed/simple; bh=hfHIahQknxvoNgKWU0yHNjwlat6rsINFZpxq+WVplxU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=AXKoEh+jdEpDbviXn5LyqvMLTjemfxDOCiT/Z0gMxyOEMPmwfFJNZfJdDfOGCX8xfpgmMDTnRPXZMzLEIzLXWXuliqtqRDT7h6+Tl5rskoK7KeDvArnogpq+B90O8NyBybBjWDm0B0JIcjm788my1uB70LXOEH0F6ZTumeFfKNA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=td2+G2/D; 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="td2+G2/D" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9CBBA1F00893; Sun, 7 Jun 2026 10:20:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780827633; bh=NR9ZxvtbPQEmf9huFzxS1zhIJdc5IzErGXB473CW4Fo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=td2+G2/D7Y89xPlOp5k6305OrfuAooFRbzmhXezDwFOGjRbMEIgYA23Se28WfkcKm RYbehq5bTcIGdoiyKXVcYhrcqXAb+pOb9o1bl8/z9pOrkmpkpI1z4KpQ72SQSJurpt OblUPff2iHHkMSuWYi18xUoQQ+V1X7h/xmR8Y1QY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jiayuan Chen , Ido Schimmel , Jakub Kicinski , Sasha Levin Subject: [PATCH 7.0 110/332] ipv6: fix possible infinite loop in rt6_fill_node() Date: Sun, 7 Jun 2026 11:57:59 +0200 Message-ID: <20260607095732.158093455@linuxfoundation.org> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260607095728.031258202@linuxfoundation.org> References: <20260607095728.031258202@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 7.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jiayuan Chen [ Upstream commit 9f72412bcf60144f252b0d6205106abf14344abc ] Sashiko reported this issue [1]. Apply the same fix as commit f8d8ce1b515a ("ipv6: fix possible infinite loop in fib6_info_uses_dev()"). Writers holding tb6_lock can list_del_rcu(&rt->fib6_siblings) without waiting for RCU readers; rt->fib6_siblings.next then still points into the old ring and this softirq-side walker never reaches &rt->fib6_siblings, causing a CPU stall. fib6_del_route() always WRITE_ONCE()s rt->fib6_nsiblings to 0 before list_del_rcu(), so an inside-loop check is a reliable detach signal. [1] https://sashiko.dev/#/patchset/20260526020227.4857-1-jiayuan.chen%40linux.dev Fixes: d9ccb18f83ea ("ipv6: Fix soft lockups in fib6_select_path under high next hop churn") Signed-off-by: Jiayuan Chen Reviewed-by: Ido Schimmel Link: https://patch.msgid.link/20260527053133.180695-1-jiayuan.chen@linux.dev Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ipv6/route.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv6/route.c b/net/ipv6/route.c index cb521700cee7ed..398e873072bbfb 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -5891,6 +5891,8 @@ static int rt6_fill_node(struct net *net, struct sk_buff *skb, goto nla_put_failure; } + if (!READ_ONCE(rt->fib6_nsiblings)) + break; } rcu_read_unlock(); -- 2.53.0