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authorDavid Howells <dhowells@redhat.com>2020-01-30 21:50:36 +0000
committerDavid Howells <dhowells@redhat.com>2020-01-30 21:50:41 +0000
commit04d36d748fac349b068ef621611f454010054c58 (patch)
tree77b18f2ab733cda5c199ea289d3008df7726fa46
parentf71dbf2fb28489a79bde0dca1c8adfb9cdb20a6b (diff)
downloadlinux-stericsson-04d36d748fac349b068ef621611f454010054c58.tar.gz
rxrpc: Fix missing active use pinning of rxrpc_local object
The introduction of a split between the reference count on rxrpc_local objects and the usage count didn't quite go far enough. A number of kernel work items need to make use of the socket to perform transmission. These also need to get an active count on the local object to prevent the socket from being closed. Fix this by getting the active count in those places. Also split out the raw active count get/put functions as these places tend to hold refs on the rxrpc_local object already, so getting and putting an extra object ref is just a waste of time. The problem can lead to symptoms like: BUG: kernel NULL pointer dereference, address: 0000000000000018 .. CPU: 2 PID: 818 Comm: kworker/u9:0 Not tainted 5.5.0-fscache+ #51 ... RIP: 0010:selinux_socket_sendmsg+0x5/0x13 ... Call Trace: security_socket_sendmsg+0x2c/0x3e sock_sendmsg+0x1a/0x46 rxrpc_send_keepalive+0x131/0x1ae rxrpc_peer_keepalive_worker+0x219/0x34b process_one_work+0x18e/0x271 worker_thread+0x1a3/0x247 kthread+0xe6/0xeb ret_from_fork+0x1f/0x30 Fixes: 730c5fd42c1e ("rxrpc: Fix local endpoint refcounting") Signed-off-by: David Howells <dhowells@redhat.com>
-rw-r--r--net/rxrpc/af_rxrpc.c2
-rw-r--r--net/rxrpc/ar-internal.h10
-rw-r--r--net/rxrpc/conn_event.c30
-rw-r--r--net/rxrpc/local_object.c18
-rw-r--r--net/rxrpc/peer_event.c42
5 files changed, 62 insertions, 40 deletions
diff --git a/net/rxrpc/af_rxrpc.c b/net/rxrpc/af_rxrpc.c
index 9d3c4d2d893a..fe42f986cd94 100644
--- a/net/rxrpc/af_rxrpc.c
+++ b/net/rxrpc/af_rxrpc.c
@@ -194,6 +194,7 @@ static int rxrpc_bind(struct socket *sock, struct sockaddr *saddr, int len)
service_in_use:
write_unlock(&local->services_lock);
rxrpc_unuse_local(local);
+ rxrpc_put_local(local);
ret = -EADDRINUSE;
error_unlock:
release_sock(&rx->sk);
@@ -899,6 +900,7 @@ static int rxrpc_release_sock(struct sock *sk)
rxrpc_purge_queue(&sk->sk_receive_queue);
rxrpc_unuse_local(rx->local);
+ rxrpc_put_local(rx->local);
rx->local = NULL;
key_put(rx->key);
rx->key = NULL;
diff --git a/net/rxrpc/ar-internal.h b/net/rxrpc/ar-internal.h
index 5e99df80e80a..94441fee85bc 100644
--- a/net/rxrpc/ar-internal.h
+++ b/net/rxrpc/ar-internal.h
@@ -1021,6 +1021,16 @@ void rxrpc_unuse_local(struct rxrpc_local *);
void rxrpc_queue_local(struct rxrpc_local *);
void rxrpc_destroy_all_locals(struct rxrpc_net *);
+static inline bool __rxrpc_unuse_local(struct rxrpc_local *local)
+{
+ return atomic_dec_return(&local->active_users) == 0;
+}
+
+static inline bool __rxrpc_use_local(struct rxrpc_local *local)
+{
+ return atomic_fetch_add_unless(&local->active_users, 1, 0) != 0;
+}
+
/*
* misc.c
*/
diff --git a/net/rxrpc/conn_event.c b/net/rxrpc/conn_event.c
index 808a4723f868..06fcff2ebbba 100644
--- a/net/rxrpc/conn_event.c
+++ b/net/rxrpc/conn_event.c
@@ -438,16 +438,12 @@ again:
/*
* connection-level event processor
*/
-void rxrpc_process_connection(struct work_struct *work)
+static void rxrpc_do_process_connection(struct rxrpc_connection *conn)
{
- struct rxrpc_connection *conn =
- container_of(work, struct rxrpc_connection, processor);
struct sk_buff *skb;
u32 abort_code = RX_PROTOCOL_ERROR;
int ret;
- rxrpc_see_connection(conn);
-
if (test_and_clear_bit(RXRPC_CONN_EV_CHALLENGE, &conn->events))
rxrpc_secure_connection(conn);
@@ -475,18 +471,32 @@ void rxrpc_process_connection(struct work_struct *work)
}
}
-out:
- rxrpc_put_connection(conn);
- _leave("");
return;
requeue_and_leave:
skb_queue_head(&conn->rx_queue, skb);
- goto out;
+ return;
protocol_error:
if (rxrpc_abort_connection(conn, ret, abort_code) < 0)
goto requeue_and_leave;
rxrpc_free_skb(skb, rxrpc_skb_freed);
- goto out;
+ return;
+}
+
+void rxrpc_process_connection(struct work_struct *work)
+{
+ struct rxrpc_connection *conn =
+ container_of(work, struct rxrpc_connection, processor);
+
+ rxrpc_see_connection(conn);
+
+ if (__rxrpc_use_local(conn->params.local)) {
+ rxrpc_do_process_connection(conn);
+ rxrpc_unuse_local(conn->params.local);
+ }
+
+ rxrpc_put_connection(conn);
+ _leave("");
+ return;
}
diff --git a/net/rxrpc/local_object.c b/net/rxrpc/local_object.c
index 3aa179efcda4..a6c1349e965d 100644
--- a/net/rxrpc/local_object.c
+++ b/net/rxrpc/local_object.c
@@ -383,14 +383,11 @@ void rxrpc_put_local(struct rxrpc_local *local)
*/
struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local)
{
- unsigned int au;
-
local = rxrpc_get_local_maybe(local);
if (!local)
return NULL;
- au = atomic_fetch_add_unless(&local->active_users, 1, 0);
- if (au == 0) {
+ if (!__rxrpc_use_local(local)) {
rxrpc_put_local(local);
return NULL;
}
@@ -404,14 +401,11 @@ struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local)
*/
void rxrpc_unuse_local(struct rxrpc_local *local)
{
- unsigned int au;
-
if (local) {
- au = atomic_dec_return(&local->active_users);
- if (au == 0)
+ if (__rxrpc_unuse_local(local)) {
+ rxrpc_get_local(local);
rxrpc_queue_local(local);
- else
- rxrpc_put_local(local);
+ }
}
}
@@ -468,7 +462,7 @@ static void rxrpc_local_processor(struct work_struct *work)
do {
again = false;
- if (atomic_read(&local->active_users) == 0) {
+ if (!__rxrpc_use_local(local)) {
rxrpc_local_destroyer(local);
break;
}
@@ -482,6 +476,8 @@ static void rxrpc_local_processor(struct work_struct *work)
rxrpc_process_local_events(local);
again = true;
}
+
+ __rxrpc_unuse_local(local);
} while (again);
rxrpc_put_local(local);
diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
index 48f67a9b1037..923b263c401b 100644
--- a/net/rxrpc/peer_event.c
+++ b/net/rxrpc/peer_event.c
@@ -364,27 +364,31 @@ static void rxrpc_peer_keepalive_dispatch(struct rxrpc_net *rxnet,
if (!rxrpc_get_peer_maybe(peer))
continue;
- spin_unlock_bh(&rxnet->peer_hash_lock);
-
- keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
- slot = keepalive_at - base;
- _debug("%02x peer %u t=%d {%pISp}",
- cursor, peer->debug_id, slot, &peer->srx.transport);
+ if (__rxrpc_use_local(peer->local)) {
+ spin_unlock_bh(&rxnet->peer_hash_lock);
+
+ keepalive_at = peer->last_tx_at + RXRPC_KEEPALIVE_TIME;
+ slot = keepalive_at - base;
+ _debug("%02x peer %u t=%d {%pISp}",
+ cursor, peer->debug_id, slot, &peer->srx.transport);
+
+ if (keepalive_at <= base ||
+ keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
+ rxrpc_send_keepalive(peer);
+ slot = RXRPC_KEEPALIVE_TIME;
+ }
- if (keepalive_at <= base ||
- keepalive_at > base + RXRPC_KEEPALIVE_TIME) {
- rxrpc_send_keepalive(peer);
- slot = RXRPC_KEEPALIVE_TIME;
+ /* A transmission to this peer occurred since last we
+ * examined it so put it into the appropriate future
+ * bucket.
+ */
+ slot += cursor;
+ slot &= mask;
+ spin_lock_bh(&rxnet->peer_hash_lock);
+ list_add_tail(&peer->keepalive_link,
+ &rxnet->peer_keepalive[slot & mask]);
+ rxrpc_unuse_local(peer->local);
}
-
- /* A transmission to this peer occurred since last we examined
- * it so put it into the appropriate future bucket.
- */
- slot += cursor;
- slot &= mask;
- spin_lock_bh(&rxnet->peer_hash_lock);
- list_add_tail(&peer->keepalive_link,
- &rxnet->peer_keepalive[slot & mask]);
rxrpc_put_peer_locked(peer);
}