[PATCH 4.17 127/324] rds: clean up loopback rds_connections on netns deletion

Greg Kroah-Hartman
2018-08-23T08:50:35Z

From: Sowmini Varadhan <sowmini.varadhan@oracle.com>

[ Upstream commit c809195f5523dd4d09403bbb1c9732d548aa0d1e ]

The RDS core module creates rds_connections based on callbacks
from rds_loop_transport when sending/receiving packets to local
addresses.

These connections will need to be cleaned up when they are
created from a netns that is not init_net, and that netns is deleted.

Add the changes aligned with the changes from
commit ebeeb1ad9b8a ("rds: tcp: use rds_destroy_pending() to synchronize
netns/module teardown and rds connection/workq management") for
rds_loop_transport

Reported-and-tested-by: syzbot+4c20b3866171ce8441d2@syzkaller.appspotmail.com
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/rds/connection.c | 11 +++++++++-
net/rds/loop.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++
net/rds/loop.h | 2 +
3 files changed, 68 insertions(+), 1 deletion(-)

--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -659,11 +659,19 @@ static void rds_conn_info(struct socket

int rds_conn_init(void)
{
+ int ret;
+
+ ret = rds_loop_net_init(); /* register pernet callback */
+ if (ret)
+ return ret;
+
rds_conn_slab = kmem_cache_create("rds_connection",
sizeof(struct rds_connection),
0, 0, NULL);
- if (!rds_conn_slab)
+ if (!rds_conn_slab) {
+ rds_loop_net_exit();
return -ENOMEM;
+ }

rds_info_register_func(RDS_INFO_CONNECTIONS, rds_conn_info);
rds_info_register_func(RDS_INFO_SEND_MESSAGES,
@@ -676,6 +684,7 @@ int rds_conn_init(void)

void rds_conn_exit(void)
{
+ rds_loop_net_exit(); /* unregister pernet callback */
rds_loop_exit();

WARN_ON(!hlist_empty(rds_conn_hash));
--- a/net/rds/loop.c
+++ b/net/rds/loop.c
@@ -33,6 +33,8 @@
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/in.h>
+#include <net/net_namespace.h>
+#include <net/netns/generic.h>

#include "rds_single_path.h"
#include "rds.h"
@@ -40,6 +42,17 @@

static DEFINE_SPINLOCK(loop_conns_lock);
static LIST_HEAD(loop_conns);
+static atomic_t rds_loop_unloading = ATOMIC_INIT(0);
+
+static void rds_loop_set_unloading(void)
+{
+ atomic_set(&rds_loop_unloading, 1);
+}
+
+static bool rds_loop_is_unloading(struct rds_connection *conn)
+{
+ return atomic_read(&rds_loop_unloading) != 0;
+}

/*
* This 'loopback' transport is a special case for flows that originate
@@ -165,6 +178,8 @@ void rds_loop_exit(void)
struct rds_loop_connection *lc, *_lc;
LIST_HEAD(tmp_list);

+ rds_loop_set_unloading();
+ synchronize_rcu();
/* avoid calling conn_destroy with irqs off */
spin_lock_irq(&loop_conns_lock);
list_splice(&loop_conns, &tmp_list);
@@ -177,6 +192,46 @@ void rds_loop_exit(void)
}
}

+static void rds_loop_kill_conns(struct net *net)
+{
+ struct rds_loop_connection *lc, *_lc;
+ LIST_HEAD(tmp_list);
+
+ spin_lock_irq(&loop_conns_lock);
+ list_for_each_entry_safe(lc, _lc, &loop_conns, loop_node) {
+ struct net *c_net = read_pnet(&lc->conn->c_net);
+
+ if (net != c_net)
+ continue;
+ list_move_tail(&lc->loop_node, &tmp_list);
+ }
+ spin_unlock_irq(&loop_conns_lock);
+
+ list_for_each_entry_safe(lc, _lc, &tmp_list, loop_node) {
+ WARN_ON(lc->conn->c_passive);
+ rds_conn_destroy(lc->conn);
+ }
+}
+
+static void __net_exit rds_loop_exit_net(struct net *net)
+{
+ rds_loop_kill_conns(net);
+}
+
+static struct pernet_operations rds_loop_net_ops = {
+ .exit = rds_loop_exit_net,
+};
+
+int rds_loop_net_init(void)
+{
+ return register_pernet_device(&rds_loop_net_ops);
+}
+
+void rds_loop_net_exit(void)
+{
+ unregister_pernet_device(&rds_loop_net_ops);
+}
+
/*
* This is missing .xmit_* because loop doesn't go through generic
* rds_send_xmit() and doesn't call rds_recv_incoming(). .listen_stop and
@@ -194,4 +249,5 @@ struct rds_transport rds_loop_transport
.inc_free = rds_loop_inc_free,
.t_name = "loopback",
.t_type = RDS_TRANS_LOOP,
+ .t_unloading = rds_loop_is_unloading,
};
--- a/net/rds/loop.h
+++ b/net/rds/loop.h
@@ -5,6 +5,8 @@
/* loop.c */
extern struct rds_transport rds_loop_transport;

+int rds_loop_net_init(void);
+void rds_loop_net_exit(void);
void rds_loop_exit(void);

#endif