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mld: change lockdep annotation for ip6_sf_socklist and ipv6_mc_socklist 

struct ip6_sf_socklist and ipv6_mc_socklist are per-socket MLD data.
These data are protected by rtnl lock, socket lock, and RCU.
So, when these are used, it verifies whether rtnl lock is acquired or not.

ip6_mc_msfget() is called by do_ipv6_getsockopt().
But caller doesn't acquire rtnl lock.
So, when these data are used in the ip6_mc_msfget() lockdep warns about it.
But accessing these is actually safe because socket lock was acquired by
do_ipv6_getsockopt().

So, it changes lockdep annotation from rtnl lock to socket lock.
(rtnl_dereference -> sock_dereference)

Locking graph for mld data is like below:

When writing mld data:
do_ipv6_setsockopt()
    rtnl_lock
    lock_sock
    (mld functions)
        idev->mc_lock(if per-interface mld data is modified)

When reading mld data:
do_ipv6_getsockopt()
    lock_sock
    ip6_mc_msfget()

Splat looks like:
=============================
WARNING: suspicious RCU usage
5.12.0-rc4+ #503 Not tainted
-----------------------------
net/ipv6/mcast.c:610 suspicious rcu_dereference_protected() usage!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
1 lock held by mcast-listener-/923:
 #0: ffff888007958a70 (sk_lock-AF_INET6){+.+.}-{0:0}, at:
ipv6_get_msfilter+0xaf/0x190

stack backtrace:
CPU: 1 PID: 923 Comm: mcast-listener- Not tainted 5.12.0-rc4+ #503
Call Trace:
 dump_stack+0xa4/0xe5
 ip6_mc_msfget+0x553/0x6c0
 ? ipv6_sock_mc_join_ssm+0x10/0x10
 ? lockdep_hardirqs_on_prepare+0x3e0/0x3e0
 ? mark_held_locks+0xb7/0x120
 ? lockdep_hardirqs_on_prepare+0x27c/0x3e0
 ? __local_bh_enable_ip+0xa5/0xf0
 ? lock_sock_nested+0x82/0xf0
 ipv6_get_msfilter+0xc3/0x190
 ? compat_ipv6_get_msfilter+0x300/0x300
 ? lock_downgrade+0x690/0x690
 do_ipv6_getsockopt.isra.6.constprop.13+0x1809/0x29e0
 ? do_ipv6_mcast_group_source+0x150/0x150
 ? register_lock_class+0x1750/0x1750
 ? kvm_sched_clock_read+0x14/0x30
 ? sched_clock+0x5/0x10
 ? sched_clock_cpu+0x18/0x170
 ? find_held_lock+0x3a/0x1c0
 ? lock_downgrade+0x690/0x690
 ? ipv6_getsockopt+0xdb/0x1b0
 ipv6_getsockopt+0xdb/0x1b0
[ ... ]

Fixes: 88e2ca3080 ("mld: convert ifmcaddr6 to RCU")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Taehee Yoo 2021-04-04 13:38:23 +00:00 committed by David S. Miller
parent 7190e9d8e1
commit 4b4b84468a
2 changed files with 25 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

48
net/ipv6/mcast.c
View File

@ -114,10 +114,13 @@ int sysctl_mld_qrv __read_mostly = MLD_QRV_DEFAULT;
#define mc_dereference(e, idev) \
rcu_dereference_protected(e, lockdep_is_held(&(idev)->mc_lock))
#define for_each_pmc_rtnl(np, pmc) \
for (pmc = rtnl_dereference((np)->ipv6_mc_list); \
#define sock_dereference(e, sk) \
rcu_dereference_protected(e, lockdep_sock_is_held(sk))
#define for_each_pmc_socklock(np, sk, pmc) \
for (pmc = sock_dereference((np)->ipv6_mc_list, sk); \
pmc; \
pmc = rtnl_dereference(pmc->next))
pmc = sock_dereference(pmc->next, sk))
#define for_each_pmc_rcu(np, pmc) \
for (pmc = rcu_dereference((np)->ipv6_mc_list); \
@ -180,7 +183,7 @@ static int __ipv6_sock_mc_join(struct sock *sk, int ifindex,
if (!ipv6_addr_is_multicast(addr))
return -EINVAL;
for_each_pmc_rtnl(np, mc_lst) {
for_each_pmc_socklock(np, sk, mc_lst) {
if ((ifindex == 0 || mc_lst->ifindex == ifindex) &&
ipv6_addr_equal(&mc_lst->addr, addr))
return -EADDRINUSE;
@ -258,7 +261,7 @@ int ipv6_sock_mc_drop(struct sock *sk, int ifindex, const struct in6_addr *addr)
return -EINVAL;
for (lnk = &np->ipv6_mc_list;
(mc_lst = rtnl_dereference(*lnk)) != NULL;
(mc_lst = sock_dereference(*lnk, sk)) != NULL;
lnk = &mc_lst->next) {
if ((ifindex == 0 || mc_lst->ifindex == ifindex) &&
ipv6_addr_equal(&mc_lst->addr, addr)) {
@ -323,7 +326,7 @@ void __ipv6_sock_mc_close(struct sock *sk)
ASSERT_RTNL();
while ((mc_lst = rtnl_dereference(np->ipv6_mc_list)) != NULL) {
while ((mc_lst = sock_dereference(np->ipv6_mc_list, sk)) != NULL) {
struct net_device *dev;
np->ipv6_mc_list = mc_lst->next;
@ -350,8 +353,11 @@ void ipv6_sock_mc_close(struct sock *sk)
if (!rcu_access_pointer(np->ipv6_mc_list))
return;
rtnl_lock();
lock_sock(sk);
__ipv6_sock_mc_close(sk);
release_sock(sk);
rtnl_unlock();
}
@ -381,7 +387,7 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
err = -EADDRNOTAVAIL;
mutex_lock(&idev->mc_lock);
for_each_pmc_rtnl(inet6, pmc) {
for_each_pmc_socklock(inet6, sk, pmc) {
if (pgsr->gsr_interface && pmc->ifindex != pgsr->gsr_interface)
continue;
if (ipv6_addr_equal(&pmc->addr, group))
@ -404,7 +410,7 @@ int ip6_mc_source(int add, int omode, struct sock *sk,
pmc->sfmode = omode;
}
psl = rtnl_dereference(pmc->sflist);
psl = sock_dereference(pmc->sflist, sk);
if (!add) {
if (!psl)
goto done; /* err = -EADDRNOTAVAIL */
@ -511,7 +517,7 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf,
goto done;
}
for_each_pmc_rtnl(inet6, pmc) {
for_each_pmc_socklock(inet6, sk, pmc) {
if (pmc->ifindex != gsf->gf_interface)
continue;
if (ipv6_addr_equal(&pmc->addr, group))
@ -552,7 +558,7 @@ int ip6_mc_msfilter(struct sock *sk, struct group_filter *gsf,
}
mutex_lock(&idev->mc_lock);
psl = rtnl_dereference(pmc->sflist);
psl = sock_dereference(pmc->sflist, sk);
if (psl) {
ip6_mc_del_src(idev, group, pmc->sfmode,
psl->sl_count, psl->sl_addr, 0);
@ -574,40 +580,32 @@ done:
int ip6_mc_msfget(struct sock *sk, struct group_filter *gsf,
struct sockaddr_storage __user *p)
{
int err, i, count, copycount;
struct ipv6_pinfo *inet6 = inet6_sk(sk);
const struct in6_addr *group;
struct ipv6_mc_socklist *pmc;
struct inet6_dev *idev;
struct ipv6_pinfo *inet6 = inet6_sk(sk);
struct ip6_sf_socklist *psl;
struct net *net = sock_net(sk);
int i, count, copycount;
group = &((struct sockaddr_in6 *)&gsf->gf_group)->sin6_addr;
if (!ipv6_addr_is_multicast(group))
return -EINVAL;
idev = ip6_mc_find_dev_rtnl(net, group, gsf->gf_interface);
if (!idev)
return -ENODEV;
err = -EADDRNOTAVAIL;
/* changes to the ipv6_mc_list require the socket lock and
* rtnl lock. We have the socket lock and rcu read lock,
* so reading the list is safe.
* rtnl lock. We have the socket lock, so reading the list is safe.
*/
for_each_pmc_rtnl(inet6, pmc) {
for_each_pmc_socklock(inet6, sk, pmc) {
if (pmc->ifindex != gsf->gf_interface)
continue;
if (ipv6_addr_equal(group, &pmc->addr))
break;
}
if (!pmc) /* must have a prior join */
return err;
return -EADDRNOTAVAIL;
gsf->gf_fmode = pmc->sfmode;
psl = rtnl_dereference(pmc->sflist);
psl = sock_dereference(pmc->sflist, sk);
count = psl ? psl->sl_count : 0;
copycount = count < gsf->gf_numsrc ? count : gsf->gf_numsrc;
@ -2600,7 +2598,7 @@ static int ip6_mc_leave_src(struct sock *sk, struct ipv6_mc_socklist *iml,
struct ip6_sf_socklist *psl;
int err;
psl = rtnl_dereference(iml->sflist);
psl = sock_dereference(iml->sflist, sk);
if (idev)
mutex_lock(&idev->mc_lock);

2
net/tipc/udp_media.c
View File

@ -414,8 +414,10 @@ static int enable_mcast(struct udp_bearer *ub, struct udp_media_addr *remote)
err = ip_mc_join_group(sk, &mreqn);
#if IS_ENABLED(CONFIG_IPV6)
} else {
lock_sock(sk);
err = ipv6_stub->ipv6_sock_mc_join(sk, ub->ifindex,
&remote->ipv6);
release_sock(sk);
#endif
}
return err;