* [BUG REPORT] ipv6: possible unsafe locking scenario
@ 2013-05-08 4:44 dingtianhong
2013-05-08 7:05 ` Cong Wang
0 siblings, 1 reply; 2+ messages in thread
From: dingtianhong @ 2013-05-08 4:44 UTC (permalink / raw)
To: David S. Miller, Eric Dumazet, Netdev, Li Zefan
hi ！
I make the kernel config with CONFIG_PROVE_LOCKING CONFIG_IOSCHED_CFQ CONFIG_PREEMPT_RT_FULL on,
and do several test case, it works well, but i notice that the log message has some Call Trace for rwlock,
it happens only once, maybe the lock use is not safe in ipv6 and need to improve.
CPU0 CPU1
---- ----
lock(&mc->mca_lock);
lock(&ndev->lock);
lock(&mc->mca_lock);
lock(&ndev->lock);
the kernel version is 3.4.24
the test case include LSB.
the problem has report to bugzilla:
https://bugzilla.kernel.org/show_bug.cgi?id=57691&GoAheadAndLogIn=1
following the message:
linux kernel: [ 5913.077146]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077149] ======================================================
Apr 20 11:01:28 euler-linux kernel: [ 5913.077150] [ INFO: possible circular locking dependency detected ]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077154] 3.4.24.05-0.1-default #1 Not tainted
Apr 20 11:01:28 euler-linux kernel: [ 5913.077155] -------------------------------------------------------
Apr 20 11:01:28 euler-linux kernel: [ 5913.077157] ksoftirqd/0/3 is trying to acquire lock:
Apr 20 11:01:28 euler-linux kernel: [ 5913.077158] (&ndev->lock){+.+...}, at: [<ffffffff8147f804>] ipv6_get_lladdr+0x74/0x120
Apr 20 11:01:28 euler-linux kernel: [ 5913.077168]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077169] but task is already holding lock:
Apr 20 11:01:28 euler-linux kernel: [ 5913.077170] (&mc->mca_lock){+.+...}, at: [<ffffffff8149d130>] mld_send_report+0x40/0x150
Apr 20 11:01:28 euler-linux kernel: [ 5913.077177]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077177] which lock already depends on the new lock.
Apr 20 11:01:28 euler-linux kernel: [ 5913.077178]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077179]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077179] the existing dependency chain (in reverse order) is:
Apr 20 11:01:28 euler-linux kernel: [ 5913.077181]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077182] -> #1 (&mc->mca_lock){+.+...}:
Apr 20 11:01:28 euler-linux kernel: [ 5913.077184] [<ffffffff810a8027>] validate_chain+0x637/0x730
Apr 20 11:01:28 euler-linux kernel: [ 5913.077191] [<ffffffff810a8417>] __lock_acquire+0x2f7/0x500
Apr 20 11:01:28 euler-linux kernel: [ 5913.077195] [<ffffffff810a8734>] lock_acquire+0x114/0x150
Apr 20 11:01:28 euler-linux kernel: [ 5913.077198] [<ffffffff814f691a>] rt_spin_lock+0x4a/0x60
Apr 20 11:01:28 euler-linux kernel: [ 5913.077203] [<ffffffff8149e4bb>] igmp6_group_added+0x3b/0x120
Apr 20 11:01:28 euler-linux kernel: [ 5913.077206] [<ffffffff8149e5d8>] ipv6_mc_up+0x38/0x60
Apr 20 11:01:28 euler-linux kernel: [ 5913.077209] [<ffffffff81480a4d>] ipv6_find_idev+0x3d/0x80
Apr 20 11:01:28 euler-linux kernel: [ 5913.077212] [<ffffffff81483175>] addrconf_notify+0x3d5/0x4b0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077215] [<ffffffff814fae3f>] notifier_call_chain+0x3f/0x80
Apr 20 11:01:28 euler-linux kernel: [ 5913.077218] [<ffffffff81073471>] raw_notifier_call_chain+0x11/0x20
Apr 20 11:01:28 euler-linux kernel: [ 5913.077224] [<ffffffff813d8722>] call_netdevice_notifiers+0x32/0x60
Apr 20 11:01:28 euler-linux kernel: [ 5913.077230] [<ffffffff813d92d4>] __dev_notify_flags+0x34/0x80
Apr 20 11:01:28 euler-linux kernel: [ 5913.077233] [<ffffffff813d9360>] dev_change_flags+0x40/0x70
Apr 20 11:01:28 euler-linux kernel: [ 5913.077236] [<ffffffff813ea627>] do_setlink+0x237/0x8a0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077240] [<ffffffff813ebb6c>] rtnl_newlink+0x3ec/0x600
Apr 20 11:01:28 euler-linux kernel: [ 5913.077243] [<ffffffff813eb4d0>] rtnetlink_rcv_msg+0x160/0x310
Apr 20 11:01:28 euler-linux kernel: [ 5913.077246] [<ffffffff814040b9>] netlink_rcv_skb+0x89/0xb0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077251] [<ffffffff813eb357>] rtnetlink_rcv+0x27/0x40
Apr 20 11:01:28 euler-linux kernel: [ 5913.077254] [<ffffffff81403e20>] netlink_unicast+0x140/0x180
Apr 20 11:01:28 euler-linux kernel: [ 5913.077257] [<ffffffff81404a9e>] netlink_sendmsg+0x33e/0x380
Apr 20 11:01:28 euler-linux kernel: [ 5913.077260] [<ffffffff813c4252>] sock_sendmsg+0x112/0x130
Apr 20 11:01:28 euler-linux kernel: [ 5913.077264] [<ffffffff813c537e>] __sys_sendmsg+0x44e/0x460
Apr 20 11:01:28 euler-linux kernel: [ 5913.077267] [<ffffffff813c5544>] sys_sendmsg+0x44/0x70
Apr 20 11:01:28 euler-linux kernel: [ 5913.077269] [<ffffffff814feab9>] system_call_fastpath+0x16/0x1b
Apr 20 11:01:28 euler-linux kernel: [ 5913.077273]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077273] -> #0 (&ndev->lock){+.+...}:
Apr 20 11:01:28 euler-linux kernel: [ 5913.077275] [<ffffffff810a798e>] check_prev_add+0x3de/0x440
Apr 20 11:01:28 euler-linux kernel: [ 5913.077278] [<ffffffff810a8027>] validate_chain+0x637/0x730
Apr 20 11:01:28 euler-linux kernel: [ 5913.077281] [<ffffffff810a8417>] __lock_acquire+0x2f7/0x500
Apr 20 11:01:28 euler-linux kernel: [ 5913.077284] [<ffffffff810a8734>] lock_acquire+0x114/0x150
Apr 20 11:01:28 euler-linux kernel: [ 5913.077287] [<ffffffff814f6c82>] rt_read_lock+0x42/0x60
Apr 20 11:01:28 euler-linux kernel: [ 5913.077290] [<ffffffff8147f804>] ipv6_get_lladdr+0x74/0x120
Apr 20 11:01:28 euler-linux kernel: [ 5913.077293] [<ffffffff8149b036>] mld_newpack+0xb6/0x160
Apr 20 11:01:28 euler-linux kernel: [ 5913.077295] [<ffffffff8149b18b>] add_grhead+0xab/0xc0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077298] [<ffffffff8149d03b>] add_grec+0x3ab/0x460
Apr 20 11:01:28 euler-linux kernel: [ 5913.077301] [<ffffffff8149d14a>] mld_send_report+0x5a/0x150
Apr 20 11:01:28 euler-linux kernel: [ 5913.077304] [<ffffffff8149f99e>] igmp6_timer_handler+0x4e/0xb0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077307] [<ffffffff8105705a>] call_timer_fn+0xca/0x1d0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077312] [<ffffffff81057b9f>] run_timer_softirq+0x1df/0x2e0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077315] [<ffffffff8104e8c7>] handle_pending_softirqs+0xf7/0x1f0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077318] [<ffffffff8104ea3b>] __do_softirq_common+0x7b/0xf0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077320] [<ffffffff8104f07f>] __thread_do_softirq+0x1af/0x210
Apr 20 11:01:28 euler-linux kernel: [ 5913.077323] [<ffffffff8104f1c1>] run_ksoftirqd+0xe1/0x1f0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077325] [<ffffffff8106c7de>] kthread+0xae/0xc0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077327] [<ffffffff814fff74>] kernel_thread_helper+0x4/0x10
Apr 20 11:01:28 euler-linux kernel: [ 5913.077332]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077332] other info that might help us debug this:
Apr 20 11:01:28 euler-linux kernel: [ 5913.077333]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077334] Possible unsafe locking scenario:
Apr 20 11:01:28 euler-linux kernel: [ 5913.077335]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077336] CPU0 CPU1
Apr 20 11:01:28 euler-linux kernel: [ 5913.077337] ---- ----
Apr 20 11:01:28 euler-linux kernel: [ 5913.077338] lock(&mc->mca_lock);
Apr 20 11:01:28 euler-linux kernel: [ 5913.077339] lock(&ndev->lock);
Apr 20 11:01:28 euler-linux kernel: [ 5913.077341] lock(&mc->mca_lock);
Apr 20 11:01:28 euler-linux kernel: [ 5913.077342] lock(&ndev->lock);
Apr 20 11:01:28 euler-linux kernel: [ 5913.077344]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077344] *** DEADLOCK ***
Apr 20 11:01:28 euler-linux kernel: [ 5913.077345]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077346] 4 locks held by ksoftirqd/0/3:
Apr 20 11:01:28 euler-linux kernel: [ 5913.077347] #0: (&per_cpu(local_softirq_lock, __cpu).lock){+.+.+.}, at: [<ffffffff8104ef5e>] __thread_do_softirq+0x8e/0x210
Apr 20 11:01:28 euler-linux kernel: [ 5913.077351] #1: (&mc->mca_timer){+.+...}, at: [<ffffffff81056f90>] call_timer_fn+0x0/0x1d0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077355] #2: (&mc->mca_lock){+.+...}, at: [<ffffffff8149d130>] mld_send_report+0x40/0x150
Apr 20 11:01:28 euler-linux kernel: [ 5913.077359] #3: (rcu_read_lock){.+.+.+}, at: [<ffffffff8147f790>] ipv6_get_lladdr+0x0/0x120
Apr 20 11:01:28 euler-linux kernel: [ 5913.077363]
Apr 20 11:01:28 euler-linux kernel: [ 5913.077363] stack backtrace:
Apr 20 11:01:28 euler-linux kernel: [ 5913.077365] Pid: 3, comm: ksoftirqd/0 Not tainted 3.4.24.05-0.1-default #1
Apr 20 11:01:28 euler-linux kernel: [ 5913.077367] Call Trace:
Apr 20 11:01:28 euler-linux kernel: [ 5913.077371] [<ffffffff810a5abf>] print_circular_bug+0x10f/0x120
Apr 20 11:01:28 euler-linux kernel: [ 5913.077375] [<ffffffff810a798e>] check_prev_add+0x3de/0x440
Apr 20 11:01:28 euler-linux kernel: [ 5913.077378] [<ffffffff810a8027>] validate_chain+0x637/0x730
Apr 20 11:01:28 euler-linux kernel: [ 5913.077381] [<ffffffff810a8417>] __lock_acquire+0x2f7/0x500
Apr 20 11:01:28 euler-linux kernel: [ 5913.077385] [<ffffffff810a8734>] lock_acquire+0x114/0x150
Apr 20 11:01:28 euler-linux kernel: [ 5913.077387] [<ffffffff8147f804>] ? ipv6_get_lladdr+0x74/0x120
Apr 20 11:01:28 euler-linux kernel: [ 5913.077391] [<ffffffff8107a5a1>] ? get_parent_ip+0x11/0x50
Apr 20 11:01:28 euler-linux kernel: [ 5913.077394] [<ffffffff814f6c82>] rt_read_lock+0x42/0x60
Apr 20 11:01:28 euler-linux kernel: [ 5913.077396] [<ffffffff8147f804>] ? ipv6_get_lladdr+0x74/0x120
Apr 20 11:01:28 euler-linux kernel: [ 5913.077399] [<ffffffff8147f804>] ipv6_get_lladdr+0x74/0x120
Apr 20 11:01:28 euler-linux kernel: [ 5913.077401] [<ffffffff8147f790>] ? if6_seq_start+0x100/0x100
Apr 20 11:01:28 euler-linux kernel: [ 5913.077404] [<ffffffff8149b036>] mld_newpack+0xb6/0x160
Apr 20 11:01:28 euler-linux kernel: [ 5913.077407] [<ffffffff810a8417>] ? __lock_acquire+0x2f7/0x500
Apr 20 11:01:28 euler-linux kernel: [ 5913.077410] [<ffffffff8149b18b>] add_grhead+0xab/0xc0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077413] [<ffffffff8149d03b>] add_grec+0x3ab/0x460
Apr 20 11:01:28 euler-linux kernel: [ 5913.077416] [<ffffffff8149f950>] ? ipv6_mc_destroy_dev+0xd0/0xd0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077419] [<ffffffff8149d14a>] mld_send_report+0x5a/0x150
Apr 20 11:01:28 euler-linux kernel: [ 5913.077422] [<ffffffff8149f99e>] igmp6_timer_handler+0x4e/0xb0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077425] [<ffffffff8105705a>] call_timer_fn+0xca/0x1d0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077427] [<ffffffff81056f90>] ? del_timer+0x130/0x130
Apr 20 11:01:28 euler-linux kernel: [ 5913.077431] [<ffffffff8149f950>] ? ipv6_mc_destroy_dev+0xd0/0xd0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077434] [<ffffffff81057b9f>] run_timer_softirq+0x1df/0x2e0
Apr 20 11:01:28 euler-linux kernel: [ 5913.077437] [<ffffffff8104e8c7>] handle_pending_softirqs+0xf7/0x1f0
Apr 20 11:01:29 euler-linux kernel: [ 5913.077439] [<ffffffff8104ea3b>] __do_softirq_common+0x7b/0xf0
Apr 20 11:01:29 euler-linux kernel: [ 5913.077442] [<ffffffff8104f07f>] __thread_do_softirq+0x1af/0x210
Apr 20 11:01:29 euler-linux kernel: [ 5913.077444] [<ffffffff8104f1c1>] run_ksoftirqd+0xe1/0x1f0
Apr 20 11:01:29 euler-linux kernel: [ 5913.077446] [<ffffffff8104f0e0>] ? __thread_do_softirq+0x210/0x210
Apr 20 11:01:29 euler-linux kernel: [ 5913.077449] [<ffffffff8104f0e0>] ? __thread_do_softirq+0x210/0x210
Apr 20 11:01:29 euler-linux kernel: [ 5913.077451] [<ffffffff8106c7de>] kthread+0xae/0xc0
Apr 20 11:01:29 euler-linux kernel: [ 5913.077455] [<ffffffff814fff74>] kernel_thread_helper+0x4/0x10
Apr 20 11:01:29 euler-linux kernel: [ 5913.077459] [<ffffffff8107ad86>] ? finish_task_switch+0x86/0x120
Apr 20 11:01:29 euler-linux kernel: [ 5913.077462] [<ffffffff814f7774>] ? retint_restore_args+0x13/0x13
Apr 20 11:01:29 euler-linux kernel: [ 5913.077465] [<ffffffff8106c730>] ? kthreadd+0x310/0x310
Apr 20 11:01:29 euler-linux kernel: [ 5913.077468] [<ffffffff814fff70>] ? gs_change+0x13/0x13
Apr 20 11:01:29 euler-linux kernel: [ 7880.565457] Adding 12284k swap on /home/swap. Priority:-2 extents:5 across:12588k
Apr 20 11:01:29 euler-linux kernel: [ 7880.832285] Adding 12284k swap on /home/swap. Priority:-2 extents:5 across:12364k
Apr 20 11:01:29 euler-linux kernel: [ 7881.278362] process `sysctl' is using deprecated sysctl (syscall) net.ipv6.neigh.default.base_reachable_time; Use net.ipv6.neigh.default.base_reachable_time_ms instead.
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [BUG REPORT] ipv6: possible unsafe locking scenario
2013-05-08 4:44 [BUG REPORT] ipv6: possible unsafe locking scenario dingtianhong
@ 2013-05-08 7:05 ` Cong Wang
0 siblings, 0 replies; 2+ messages in thread
From: Cong Wang @ 2013-05-08 7:05 UTC (permalink / raw)
To: netdev
On Wed, 08 May 2013 at 04:44 GMT, dingtianhong <dingtianhong@huawei.com> wrote:
> hi ！
> I make the kernel config with CONFIG_PROVE_LOCKING CONFIG_IOSCHED_CFQ CONFIG_PREEMPT_RT_FULL on,
> and do several test case, it works well, but i notice that the log message has some Call Trace for rwlock,
> it happens only once, maybe the lock use is not safe in ipv6 and need to improve.
>
> CPU0 CPU1
> ---- ----
> lock(&mc->mca_lock);
> lock(&ndev->lock);
> lock(&mc->mca_lock);
> lock(&ndev->lock);
>
Can you try the following patch?
Thanks.
-------------------->
diff --git a/include/net/addrconf.h b/include/net/addrconf.h
index 84a6440..dbc6db7 100644
--- a/include/net/addrconf.h
+++ b/include/net/addrconf.h
@@ -86,6 +86,9 @@ 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 d1ab6ab..a937092 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)
+{
+ int err = -EADDRNOTAVAIL;
+ struct inet6_ifaddr *ifp;
+
+ 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 bfa6cc3..c3998c2 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);
}
^ permalink raw reply related [flat|nested] 2+ messages in thread
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2013-05-08 4:44 [BUG REPORT] ipv6: possible unsafe locking scenario dingtianhong
2013-05-08 7:05 ` Cong Wang
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