From patchwork Tue Mar 20 14:44:55 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: David Lebrun X-Patchwork-Id: 888249 X-Patchwork-Delegate: davem@davemloft.net Return-Path: X-Original-To: patchwork-incoming-netdev@ozlabs.org Delivered-To: patchwork-incoming-netdev@ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=netdev-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.b="O1Qrih5G"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 405G1p3Mfdz9s0r for ; Wed, 21 Mar 2018 01:45:18 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751372AbeCTOpP (ORCPT ); Tue, 20 Mar 2018 10:45:15 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:38354 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751308AbeCTOpN (ORCPT ); Tue, 20 Mar 2018 10:45:13 -0400 Received: by mail-wm0-f67.google.com with SMTP id l16so4043210wmh.3 for ; Tue, 20 Mar 2018 07:45:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id; bh=mhsU6DqlSFJ8Wn/o7EUY3XJJm7RlCKPBkPoodQufYuk=; b=O1Qrih5GiEwlWxLzt5j9b3mmPZPsGh4pEvE7u/0W7dgG34ikikUCjtRXUVg8CIYRxp Hayn9aFT1jZNXwKN39kG5ngSH4ydRMXDVH7wruxXAyKzY1x+UMb5fgkZKgzl6DfCTT+9 iwcmZK6y87j96n6UM779dsEo6s7Z4hXTmCQHbpJrpoyfeAcSbyYqPEIMgW8XRnuSLQBV aMk2vGDd72nGuej9rx5Y4ANjlRtOEwBoxz8TlP+dTPtK6vFdKI+dEiHVdvu5NVTIIcD9 EvScgI5kmuMYF1sXFyTFZSevut0C3yObPeZ04AWXgIoKhYOnDVkg0anMEat52mOb9jCw D/rA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id; bh=mhsU6DqlSFJ8Wn/o7EUY3XJJm7RlCKPBkPoodQufYuk=; b=DiWqirFs9yp49KiiDXCWAbrY4vgbEtgg9d/Im1N2aUT86LhOiSwyVQ+uhmyP+pCrTe 4r/giogl8Ki1tifOq1o18CN9BpeMsFfiffPb2DOVcDaU4u7CcfLMPWzleuqN6yC7YAAn UQOpGAzbAXfXMp23OvHaG+kslDNlhRUzTN1MfqpYtJo6n1MwwU7rZ8bolpJzdakymQfZ 2WQ7CQ5YbqrLFk9a3deLW69PbUlloQVNMTkqGvfZHeU1enaE/SvFgwBTALNNGz5DS/xT K47f+86EpCKzFAcFMC0stvBjL8Z4Ygp3dZJIqxkj50HQgP4wGpMTnw9BdiHwQiJ3it8h Ng0Q== X-Gm-Message-State: AElRT7HB4+wC3ygSQ5hR9+gpjb7Y8Ro/1zcSSKVRcyinsgNUxOS/4+Uj c1selSV+ODg9p+li4E/bz73XQjuqrgM= X-Google-Smtp-Source: AG47ELtpP6nsRbikj3FCRbOqXHG6/Sh/SPc9pAns+bofHp18PcSuj9vY9HzMHoO5LTZSspjg3G6LlA== X-Received: by 10.80.149.68 with SMTP id v4mr17934298eda.236.1521557111788; Tue, 20 Mar 2018 07:45:11 -0700 (PDT) Received: from suzaku.dub.corp.google.com ([2620:0:1040:2012:569d:fe6f:1c9c:e2b]) by smtp.gmail.com with ESMTPSA id l91sm1893906ede.50.2018.03.20.07.45.10 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 20 Mar 2018 07:45:11 -0700 (PDT) From: David Lebrun To: netdev@vger.kernel.org Cc: David Lebrun , David Lebrun Subject: [PATCH net] ipv6: sr: fix scheduling in RCU when creating seg6 lwtunnel state Date: Tue, 20 Mar 2018 14:44:55 +0000 Message-Id: <20180320144456.223556-1-dav.lebrun@gmail.com> X-Mailer: git-send-email 2.16.2.804.g6dcf76e118-goog Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: David Lebrun The seg6_build_state() function is called with RCU read lock held, so we cannot use GFP_KERNEL. This patch uses GFP_ATOMIC instead. [ 92.770271] ============================= [ 92.770628] WARNING: suspicious RCU usage [ 92.770921] 4.16.0-rc4+ #12 Not tainted [ 92.771277] ----------------------------- [ 92.771585] ./include/linux/rcupdate.h:302 Illegal context switch in RCU read-side critical section! [ 92.772279] [ 92.772279] other info that might help us debug this: [ 92.772279] [ 92.773067] [ 92.773067] rcu_scheduler_active = 2, debug_locks = 1 [ 92.773514] 2 locks held by ip/2413: [ 92.773765] #0: (rtnl_mutex){+.+.}, at: [<00000000e5461720>] rtnetlink_rcv_msg+0x441/0x4d0 [ 92.774377] #1: (rcu_read_lock){....}, at: [<00000000df4f161e>] lwtunnel_build_state+0x59/0x210 [ 92.775065] [ 92.775065] stack backtrace: [ 92.775371] CPU: 0 PID: 2413 Comm: ip Not tainted 4.16.0-rc4+ #12 [ 92.775791] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1.fc27 04/01/2014 [ 92.776608] Call Trace: [ 92.776852] dump_stack+0x7d/0xbc [ 92.777130] __schedule+0x133/0xf00 [ 92.777393] ? unwind_get_return_address_ptr+0x50/0x50 [ 92.777783] ? __sched_text_start+0x8/0x8 [ 92.778073] ? rcu_is_watching+0x19/0x30 [ 92.778383] ? kernel_text_address+0x49/0x60 [ 92.778800] ? __kernel_text_address+0x9/0x30 [ 92.779241] ? unwind_get_return_address+0x29/0x40 [ 92.779727] ? pcpu_alloc+0x102/0x8f0 [ 92.780101] _cond_resched+0x23/0x50 [ 92.780459] __mutex_lock+0xbd/0xad0 [ 92.780818] ? pcpu_alloc+0x102/0x8f0 [ 92.781194] ? seg6_build_state+0x11d/0x240 [ 92.781611] ? save_stack+0x9b/0xb0 [ 92.781965] ? __ww_mutex_wakeup_for_backoff+0xf0/0xf0 [ 92.782480] ? seg6_build_state+0x11d/0x240 [ 92.782925] ? lwtunnel_build_state+0x1bd/0x210 [ 92.783393] ? ip6_route_info_create+0x687/0x1640 [ 92.783846] ? ip6_route_add+0x74/0x110 [ 92.784236] ? inet6_rtm_newroute+0x8a/0xd0 Fixes: 6c8702c60b886 ("ipv6: sr: add support for SRH encapsulation and injection with lwtunnels") Signed-off-by: David Lebrun --- net/ipv6/seg6_iptunnel.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv6/seg6_iptunnel.c b/net/ipv6/seg6_iptunnel.c index bd6cc688bd19..8367b859a934 100644 --- a/net/ipv6/seg6_iptunnel.c +++ b/net/ipv6/seg6_iptunnel.c @@ -418,7 +418,7 @@ static int seg6_build_state(struct nlattr *nla, slwt = seg6_lwt_lwtunnel(newts); - err = dst_cache_init(&slwt->cache, GFP_KERNEL); + err = dst_cache_init(&slwt->cache, GFP_ATOMIC); if (err) { kfree(newts); return err;