aboutsummaryrefslogtreecommitdiff
path: root/net
diff options
context:
space:
mode:
authorAmerigo Wang <amwang@redhat.com>2013-06-29 21:30:49 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-07-28 16:29:49 -0700
commit36bddbad5049d3f3916abc9f594526d47ad3ab84 (patch)
treed5aaf3bc7cc3fb8985fbaff65bc5b844b2173655 /net
parentda04e7df0494a9a6ccfe2aada8a262e38c284914 (diff)
downloadvexpress-lsk-36bddbad5049d3f3916abc9f594526d47ad3ab84.tar.gz
ipv6,mcast: always hold idev->lock before mca_lock
[ Upstream commit 8965779d2c0e6ab246c82a405236b1fb2adae6b2, with some bits from commit b7b1bfce0bb68bd8f6e62a28295922785cc63781 ("ipv6: split duplicate address detection and router solicitation timer") to get the __ipv6_get_lladdr() used by this patch. ] 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@huawei.com> Cc: dingtianhong <dingtianhong@huawei.com> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: David S. Miller <davem@davemloft.net> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Tested-by: Ding Tianhong <dingtianhong@huawei.com> Tested-by: Chen Weilong <chenweilong@huawei.com> Signed-off-by: Cong Wang <amwang@redhat.com> Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
-rw-r--r--net/ipv6/addrconf.c28
-rw-r--r--net/ipv6/mcast.c18
2 files changed, 28 insertions, 18 deletions
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 4ab4c38958c..fb8c94c4ab8 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -1448,6 +1448,23 @@ 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)
{
@@ -1457,17 +1474,8 @@ 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 bfa6cc36ef2..c3998c2bbc5 100644
--- a/net/ipv6/mcast.c
+++ b/net/ipv6/mcast.c
@@ -1343,8 +1343,9 @@ static void ip6_mc_hdr(struct sock *sk, struct sk_buff *skb,
hdr->daddr = *daddr;
}
-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;
@@ -1369,7 +1370,7 @@ 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.
@@ -1465,7 +1466,7 @@ 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));
@@ -1485,7 +1486,8 @@ 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;
@@ -1514,7 +1516,7 @@ 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;
@@ -1541,7 +1543,7 @@ 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;
}
@@ -1596,8 +1598,8 @@ 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;
@@ -1609,7 +1611,6 @@ 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])
@@ -1619,6 +1620,7 @@ 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);
}