From patchwork Wed Mar 9 00:27:30 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 594535 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from huckleberry.canonical.com (huckleberry.canonical.com [91.189.94.19]) by ozlabs.org (Postfix) with ESMTP id 73EA31401B5; Wed, 9 Mar 2016 11:27:50 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=huckleberry.canonical.com) by huckleberry.canonical.com with esmtp (Exim 4.76) (envelope-from ) id 1adRyd-0004jK-I7; Wed, 09 Mar 2016 00:27:47 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by huckleberry.canonical.com with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.76) (envelope-from ) id 1adRyQ-0004d0-Nl for kernel-team@lists.ubuntu.com; Wed, 09 Mar 2016 00:27:34 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1adRyQ-00031J-9P; Wed, 09 Mar 2016 00:27:34 +0000 Received: from kamal by fourier with local (Exim 4.86) (envelope-from ) id 1adRyN-0007CP-K7; Tue, 08 Mar 2016 16:27:31 -0800 From: Kamal Mostafa To: "subashab@codeaurora.org" Subject: [3.19.y-ckt stable] Patch "ipv6: addrconf: Fix recursive spin lock call" has been added to the 3.19.y-ckt tree Date: Tue, 8 Mar 2016 16:27:30 -0800 Message-Id: <1457483250-27637-1-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 2.7.0 X-Extended-Stable: 3.19 Cc: Kamal Mostafa , kernel-team@lists.ubuntu.com, Eric Dumazet , Hannes Frederic Sowa , Erik Kline , "David S . Miller" X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.14 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: kernel-team-bounces@lists.ubuntu.com This is a note to let you know that I have just added a patch titled ipv6: addrconf: Fix recursive spin lock call to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree which can be found at: http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue This patch is scheduled to be released in version 3.19.8-ckt16. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.19.y-ckt tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ---8<------------------------------------------------------------ From e51919ee7a1714205ed9b6b8d34b2565cc6dbd34 Mon Sep 17 00:00:00 2001 From: "subashab@codeaurora.org" Date: Tue, 2 Feb 2016 02:11:10 +0000 Subject: ipv6: addrconf: Fix recursive spin lock call [ Upstream commit 16186a82de1fdd868255448274e64ae2616e2640 ] A rcu stall with the following backtrace was seen on a system with forwarding, optimistic_dad and use_optimistic set. To reproduce, set these flags and allow ipv6 autoconf. This occurs because the device write_lock is acquired while already holding the read_lock. Back trace below - INFO: rcu_preempt self-detected stall on CPU { 1} (t=2100 jiffies g=3992 c=3991 q=4471) <6> Task dump for CPU 1: <2> kworker/1:0 R running task 12168 15 2 0x00000002 <2> Workqueue: ipv6_addrconf addrconf_dad_work <6> Call trace: <2> [] el1_irq+0x68/0xdc <2> [] _raw_write_lock_bh+0x20/0x30 <2> [] __ipv6_dev_ac_inc+0x64/0x1b4 <2> [] addrconf_join_anycast+0x9c/0xc4 <2> [] __ipv6_ifa_notify+0x160/0x29c <2> [] ipv6_ifa_notify+0x50/0x70 <2> [] addrconf_dad_work+0x314/0x334 <2> [] process_one_work+0x244/0x3fc <2> [] worker_thread+0x2f8/0x418 <2> [] kthread+0xe0/0xec v2: do addrconf_dad_kick inside read lock and then acquire write lock for ipv6_ifa_notify as suggested by Eric Fixes: 7fd2561e4ebdd ("net: ipv6: Add a sysctl to make optimistic addresses useful candidates") Cc: Eric Dumazet Cc: Erik Kline Cc: Hannes Frederic Sowa Signed-off-by: Subash Abhinov Kasiviswanathan Acked-by: Hannes Frederic Sowa Acked-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Kamal Mostafa --- net/ipv6/addrconf.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) -- 2.7.0 diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index ece842c..e0ffd02 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -3214,6 +3214,7 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp) { struct inet6_dev *idev = ifp->idev; struct net_device *dev = idev->dev; + bool notify = false; addrconf_join_solict(dev, &ifp->addr); @@ -3259,7 +3260,7 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp) /* Because optimistic nodes can use this address, * notify listeners. If DAD fails, RTM_DELADDR is sent. */ - ipv6_ifa_notify(RTM_NEWADDR, ifp); + notify = true; } } @@ -3267,6 +3268,8 @@ static void addrconf_dad_begin(struct inet6_ifaddr *ifp) out: spin_unlock(&ifp->lock); read_unlock_bh(&idev->lock); + if (notify) + ipv6_ifa_notify(RTM_NEWADDR, ifp); } static void addrconf_dad_start(struct inet6_ifaddr *ifp)