3.8.13.6 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Amerigo Wang <amwang@xxxxxxxxxx> commit 8965779d2c0e6ab246c82a405236b1fb2adae6b2 upstream. dingtianhong reported the following deadlock detected by lockdep: ====================================================== [ INFO: possible circular locking dependency detected ] 3.4.24.05-0.1-default #1 Not tainted ------------------------------------------------------- ksoftirqd/0/3 is trying to acquire lock: (&ndev->lock){+.+...}, at: [<ffffffff8147f804>] ipv6_get_lladdr+0x74/0x120 but task is already holding lock: (&mc->mca_lock){+.+...}, at: [<ffffffff8149d130>] mld_send_report+0x40/0x150 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&mc->mca_lock){+.+...}: [<ffffffff810a8027>] validate_chain+0x637/0x730 [<ffffffff810a8417>] __lock_acquire+0x2f7/0x500 [<ffffffff810a8734>] lock_acquire+0x114/0x150 [<ffffffff814f691a>] rt_spin_lock+0x4a/0x60 [<ffffffff8149e4bb>] igmp6_group_added+0x3b/0x120 [<ffffffff8149e5d8>] ipv6_mc_up+0x38/0x60 [<ffffffff81480a4d>] ipv6_find_idev+0x3d/0x80 [<ffffffff81483175>] addrconf_notify+0x3d5/0x4b0 [<ffffffff814fae3f>] notifier_call_chain+0x3f/0x80 [<ffffffff81073471>] raw_notifier_call_chain+0x11/0x20 [<ffffffff813d8722>] call_netdevice_notifiers+0x32/0x60 [<ffffffff813d92d4>] __dev_notify_flags+0x34/0x80 [<ffffffff813d9360>] dev_change_flags+0x40/0x70 [<ffffffff813ea627>] do_setlink+0x237/0x8a0 [<ffffffff813ebb6c>] rtnl_newlink+0x3ec/0x600 [<ffffffff813eb4d0>] rtnetlink_rcv_msg+0x160/0x310 [<ffffffff814040b9>] netlink_rcv_skb+0x89/0xb0 [<ffffffff813eb357>] rtnetlink_rcv+0x27/0x40 [<ffffffff81403e20>] netlink_unicast+0x140/0x180 [<ffffffff81404a9e>] netlink_sendmsg+0x33e/0x380 [<ffffffff813c4252>] sock_sendmsg+0x112/0x130 [<ffffffff813c537e>] __sys_sendmsg+0x44e/0x460 [<ffffffff813c5544>] sys_sendmsg+0x44/0x70 [<ffffffff814feab9>] system_call_fastpath+0x16/0x1b -> #0 (&ndev->lock){+.+...}: [<ffffffff810a798e>] check_prev_add+0x3de/0x440 [<ffffffff810a8027>] validate_chain+0x637/0x730 [<ffffffff810a8417>] __lock_acquire+0x2f7/0x500 [<ffffffff810a8734>] lock_acquire+0x114/0x150 [<ffffffff814f6c82>] rt_read_lock+0x42/0x60 [<ffffffff8147f804>] ipv6_get_lladdr+0x74/0x120 [<ffffffff8149b036>] mld_newpack+0xb6/0x160 [<ffffffff8149b18b>] add_grhead+0xab/0xc0 [<ffffffff8149d03b>] add_grec+0x3ab/0x460 [<ffffffff8149d14a>] mld_send_report+0x5a/0x150 [<ffffffff8149f99e>] igmp6_timer_handler+0x4e/0xb0 [<ffffffff8105705a>] call_timer_fn+0xca/0x1d0 [<ffffffff81057b9f>] run_timer_softirq+0x1df/0x2e0 [<ffffffff8104e8c7>] handle_pending_softirqs+0xf7/0x1f0 [<ffffffff8104ea3b>] __do_softirq_common+0x7b/0xf0 [<ffffffff8104f07f>] __thread_do_softirq+0x1af/0x210 [<ffffffff8104f1c1>] run_ksoftirqd+0xe1/0x1f0 [<ffffffff8106c7de>] kthread+0xae/0xc0 [<ffffffff814fff74>] kernel_thread_helper+0x4/0x10 actually we can just hold idev->lock before taking pmc->mca_lock, and avoid taking idev->lock again when iterating idev->addr_list, since the upper callers of mld_newpack() already take read_lock_bh(&idev->lock). Reported-by: dingtianhong <dingtianhong@xxxxxxxxxx> Cc: dingtianhong <dingtianhong@xxxxxxxxxx> Cc: Hideaki YOSHIFUJI <yoshfuji@xxxxxxxxxxxxxx> Cc: David S. Miller <davem@xxxxxxxxxxxxx> Cc: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx> Tested-by: Ding Tianhong <dingtianhong@xxxxxxxxxx> Tested-by: Chen Weilong <chenweilong@xxxxxxxxxx> Signed-off-by: Cong Wang <amwang@xxxxxxxxxx> Acked-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> [ luis: backported to 3.5, based on the davem's backport to 3.4: - get __ipv6_get_lladdr() from commit b7b1bfce0bb68bd8f6e62a28295922785cc63781 ("ipv6: split duplicate address detection and router solicitation timer") ] Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx> Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx> --- include/net/addrconf.h | 3 +++ net/ipv6/addrconf.c | 28 ++++++++++++++++++---------- net/ipv6/mcast.c | 18 ++++++++++-------- 3 files changed, 31 insertions(+), 18 deletions(-) diff --git a/include/net/addrconf.h b/include/net/addrconf.h index 594abec..697d911 100644 --- a/include/net/addrconf.h +++ b/include/net/addrconf.h @@ -82,6 +82,9 @@ extern int ipv6_dev_get_saddr(struct net *net, const struct in6_addr *daddr, unsigned int srcprefs, struct in6_addr *saddr); +extern int __ipv6_get_lladdr(struct inet6_dev *idev, + struct in6_addr *addr, + unsigned char banned_flags); extern int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr, unsigned char banned_flags); diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c index c6987a9..7b54fff 100644 --- a/net/ipv6/addrconf.c +++ b/net/ipv6/addrconf.c @@ -1370,6 +1370,23 @@ try_nextdev: } EXPORT_SYMBOL(ipv6_dev_get_saddr); +int __ipv6_get_lladdr(struct inet6_dev *idev, struct in6_addr *addr, + unsigned char banned_flags) +{ + struct inet6_ifaddr *ifp; + int err = -EADDRNOTAVAIL; + + list_for_each_entry(ifp, &idev->addr_list, if_list) { + if (ifp->scope == IFA_LINK && + !(ifp->flags & banned_flags)) { + *addr = ifp->addr; + err = 0; + break; + } + } + return err; +} + int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr, unsigned char banned_flags) { @@ -1379,17 +1396,8 @@ int ipv6_get_lladdr(struct net_device *dev, struct in6_addr *addr, rcu_read_lock(); idev = __in6_dev_get(dev); if (idev) { - struct inet6_ifaddr *ifp; - read_lock_bh(&idev->lock); - list_for_each_entry(ifp, &idev->addr_list, if_list) { - if (ifp->scope == IFA_LINK && - !(ifp->flags & banned_flags)) { - *addr = ifp->addr; - err = 0; - break; - } - } + err = __ipv6_get_lladdr(idev, addr, banned_flags); read_unlock_bh(&idev->lock); } rcu_read_unlock(); diff --git a/net/ipv6/mcast.c b/net/ipv6/mcast.c index 28dfa5f..79fa628 100644 --- a/net/ipv6/mcast.c +++ b/net/ipv6/mcast.c @@ -1340,8 +1340,9 @@ mld_scount(struct ifmcaddr6 *pmc, int type, int gdeleted, int sdeleted) return scount; } -static struct sk_buff *mld_newpack(struct net_device *dev, int size) +static struct sk_buff *mld_newpack(struct inet6_dev *idev, int size) { + struct net_device *dev = idev->dev; struct net *net = dev_net(dev); struct sock *sk = net->ipv6.igmp_sk; struct sk_buff *skb; @@ -1366,7 +1367,7 @@ static struct sk_buff *mld_newpack(struct net_device *dev, int size) skb_reserve(skb, hlen); - if (ipv6_get_lladdr(dev, &addr_buf, IFA_F_TENTATIVE)) { + if (__ipv6_get_lladdr(idev, &addr_buf, IFA_F_TENTATIVE)) { /* <draft-ietf-magma-mld-source-05.txt>: * use unspecified address as the source address * when a valid link-local address is not available. @@ -1462,7 +1463,7 @@ static struct sk_buff *add_grhead(struct sk_buff *skb, struct ifmcaddr6 *pmc, struct mld2_grec *pgr; if (!skb) - skb = mld_newpack(dev, dev->mtu); + skb = mld_newpack(pmc->idev, dev->mtu); if (!skb) return NULL; pgr = (struct mld2_grec *)skb_put(skb, sizeof(struct mld2_grec)); @@ -1482,7 +1483,8 @@ static struct sk_buff *add_grhead(struct sk_buff *skb, struct ifmcaddr6 *pmc, static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc, int type, int gdeleted, int sdeleted) { - struct net_device *dev = pmc->idev->dev; + struct inet6_dev *idev = pmc->idev; + struct net_device *dev = idev->dev; struct mld2_report *pmr; struct mld2_grec *pgr = NULL; struct ip6_sf_list *psf, *psf_next, *psf_prev, **psf_list; @@ -1511,7 +1513,7 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc, AVAILABLE(skb) < grec_size(pmc, type, gdeleted, sdeleted)) { if (skb) mld_sendpack(skb); - skb = mld_newpack(dev, dev->mtu); + skb = mld_newpack(idev, dev->mtu); } } first = 1; @@ -1538,7 +1540,7 @@ static struct sk_buff *add_grec(struct sk_buff *skb, struct ifmcaddr6 *pmc, pgr->grec_nsrcs = htons(scount); if (skb) mld_sendpack(skb); - skb = mld_newpack(dev, dev->mtu); + skb = mld_newpack(idev, dev->mtu); first = 1; scount = 0; } @@ -1593,8 +1595,8 @@ static void mld_send_report(struct inet6_dev *idev, struct ifmcaddr6 *pmc) struct sk_buff *skb = NULL; int type; + read_lock_bh(&idev->lock); if (!pmc) { - read_lock_bh(&idev->lock); for (pmc=idev->mc_list; pmc; pmc=pmc->next) { if (pmc->mca_flags & MAF_NOREPORT) continue; @@ -1606,7 +1608,6 @@ static void mld_send_report(struct inet6_dev *idev, struct ifmcaddr6 *pmc) skb = add_grec(skb, pmc, type, 0, 0); spin_unlock_bh(&pmc->mca_lock); } - read_unlock_bh(&idev->lock); } else { spin_lock_bh(&pmc->mca_lock); if (pmc->mca_sfcount[MCAST_EXCLUDE]) @@ -1616,6 +1617,7 @@ static void mld_send_report(struct inet6_dev *idev, struct ifmcaddr6 *pmc) skb = add_grec(skb, pmc, type, 0, 0); spin_unlock_bh(&pmc->mca_lock); } + read_unlock_bh(&idev->lock); if (skb) mld_sendpack(skb); } -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html