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authorEric Dumazet <edumazet@google.com>2016-04-01 08:52:16 -0700
committerDavid S. Miller <davem@davemloft.net>2016-04-04 22:11:19 -0400
commit3a5d1c0e7cb5ba91aabbd7e28626e3cc925f8093 (patch)
tree14db12b0567eaaa34d3d9850645daf8b54e8689f /include/net/request_sock.h
parent2d331915a04144dad738e725769d8fac06ef6155 (diff)
downloadlinux-3a5d1c0e7cb5ba91aabbd7e28626e3cc925f8093.tar.bz2
inet: reqsk_alloc() needs to take care of dead listeners
We'll soon no longer take a refcount on listeners, so reqsk_alloc() can not assume a listener refcount is not zero. We need to use atomic_inc_not_zero() Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'include/net/request_sock.h')
-rw-r--r--include/net/request_sock.h31
1 files changed, 15 insertions, 16 deletions
diff --git a/include/net/request_sock.h b/include/net/request_sock.h
index f49759decb28..6ebe13eb1c4c 100644
--- a/include/net/request_sock.h
+++ b/include/net/request_sock.h
@@ -85,24 +85,23 @@ reqsk_alloc(const struct request_sock_ops *ops, struct sock *sk_listener,
struct request_sock *req;
req = kmem_cache_alloc(ops->slab, GFP_ATOMIC | __GFP_NOWARN);
-
- if (req) {
- req->rsk_ops = ops;
- if (attach_listener) {
- sock_hold(sk_listener);
- req->rsk_listener = sk_listener;
- } else {
- req->rsk_listener = NULL;
+ if (!req)
+ return NULL;
+ req->rsk_listener = NULL;
+ if (attach_listener) {
+ if (unlikely(!atomic_inc_not_zero(&sk_listener->sk_refcnt))) {
+ kmem_cache_free(ops->slab, req);
+ return NULL;
}
- req_to_sk(req)->sk_prot = sk_listener->sk_prot;
- sk_node_init(&req_to_sk(req)->sk_node);
- sk_tx_queue_clear(req_to_sk(req));
- req->saved_syn = NULL;
- /* Following is temporary. It is coupled with debugging
- * helpers in reqsk_put() & reqsk_free()
- */
- atomic_set(&req->rsk_refcnt, 0);
+ req->rsk_listener = sk_listener;
}
+ req->rsk_ops = ops;
+ req_to_sk(req)->sk_prot = sk_listener->sk_prot;
+ sk_node_init(&req_to_sk(req)->sk_node);
+ sk_tx_queue_clear(req_to_sk(req));
+ req->saved_syn = NULL;
+ atomic_set(&req->rsk_refcnt, 0);
+
return req;
}