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tipc: Fix tipc_sk_reinit race conditions 

There are two problems with the function tipc_sk_reinit.  Firstly
it's doing a manual walk over an rhashtable.  This is broken as
an rhashtable can be resized and if you manually walk over it
during a resize then you may miss entries.

Secondly it's missing memory barriers as previously the code used
spinlocks which provide the barriers implicitly.

This patch fixes both problems.

Fixes: 07f6c4bc04 ("tipc: convert tipc reference table to...")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Herbert Xu 2017-02-11 19:26:46 +08:00 committed by David S. Miller
parent 98687f426b
commit 40f9f43970
2 changed files with 23 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
net/tipc/net.c
View File

@ -110,6 +110,10 @@ int tipc_net_start(struct net *net, u32 addr)
char addr_string[16];
tn->own_addr = addr;
/* Ensure that the new address is visible before we reinit. */
smp_mb();
tipc_named_reinit(net);
tipc_sk_reinit(net);

30
net/tipc/socket.c
View File

@ -430,8 +430,6 @@ static int tipc_sk_create(struct net *net, struct socket *sock,
INIT_LIST_HEAD(&tsk->cong_links);
msg = &tsk->phdr;
tn = net_generic(sock_net(sk), tipc_net_id);
tipc_msg_init(tn->own_addr, msg, TIPC_LOW_IMPORTANCE, TIPC_NAMED_MSG,
NAMED_H_SIZE, 0);
/* Finish initializing socket data structures */
sock->ops = ops;
@ -441,6 +439,13 @@ static int tipc_sk_create(struct net *net, struct socket *sock,
pr_warn("Socket create failed; port number exhausted\n");
return -EINVAL;
}
/* Ensure tsk is visible before we read own_addr. */
smp_mb();
tipc_msg_init(tn->own_addr, msg, TIPC_LOW_IMPORTANCE, TIPC_NAMED_MSG,
NAMED_H_SIZE, 0);
msg_set_origport(msg, tsk->portid);
setup_timer(&sk->sk_timer, tipc_sk_timeout, (unsigned long)tsk);
sk->sk_shutdown = 0;
@ -2234,24 +2239,27 @@ static int tipc_sk_withdraw(struct tipc_sock *tsk, uint scope,
void tipc_sk_reinit(struct net *net)
{
struct tipc_net *tn = net_generic(net, tipc_net_id);
const struct bucket_table *tbl;
struct rhash_head *pos;
struct rhashtable_iter iter;
struct tipc_sock *tsk;
struct tipc_msg *msg;
int i;
rcu_read_lock();
tbl = rht_dereference_rcu((&tn->sk_rht)->tbl, &tn->sk_rht);
for (i = 0; i < tbl->size; i++) {
rht_for_each_entry_rcu(tsk, pos, tbl, i, node) {
rhashtable_walk_enter(&tn->sk_rht, &iter);
do {
tsk = ERR_PTR(rhashtable_walk_start(&iter));
if (tsk)
continue;
while ((tsk = rhashtable_walk_next(&iter)) && !IS_ERR(tsk)) {
spin_lock_bh(&tsk->sk.sk_lock.slock);
msg = &tsk->phdr;
msg_set_prevnode(msg, tn->own_addr);
msg_set_orignode(msg, tn->own_addr);
spin_unlock_bh(&tsk->sk.sk_lock.slock);
}
}
rcu_read_unlock();
rhashtable_walk_stop(&iter);
} while (tsk == ERR_PTR(-EAGAIN));
}
static struct tipc_sock *tipc_sk_lookup(struct net *net, u32 portid)