RDMA/rxe: Remove the direct link to net_device

The similar patch in siw is in the link:
https://git.kernel.org/rdma/rdma/c/16b87037b48889

This problem also occurred in RXE. The following analyze this problem.
In the following Call Traces:
"
BUG: KASAN: slab-use-after-free in dev_get_flags+0x188/0x1d0 net/core/dev.c:8782
Read of size 4 at addr ffff8880554640b0 by task kworker/1:4/5295

CPU: 1 UID: 0 PID: 5295 Comm: kworker/1:4 Not tainted
6.12.0-rc3-syzkaller-00399-g9197b73fd7bb #0
Hardware name: Google Compute Engine/Google Compute Engine,
BIOS Google 09/13/2024
Workqueue: infiniband ib_cache_event_task
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
dev_get_flags+0x188/0x1d0 net/core/dev.c:8782
rxe_query_port+0x12d/0x260 drivers/infiniband/sw/rxe/rxe_verbs.c:60
__ib_query_port drivers/infiniband/core/device.c:2111 [inline]
ib_query_port+0x168/0x7d0 drivers/infiniband/core/device.c:2143
ib_cache_update+0x1a9/0xb80 drivers/infiniband/core/cache.c:1494
ib_cache_event_task+0xf3/0x1e0 drivers/infiniband/core/cache.c:1568
process_one_work kernel/workqueue.c:3229 [inline]
process_scheduled_works+0xa65/0x1850 kernel/workqueue.c:3310
worker_thread+0x870/0xd30 kernel/workqueue.c:3391
kthread+0x2f2/0x390 kernel/kthread.c:389
ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
</TASK>
"

1). In the link [1],

"
infiniband syz2: set down
"

This means that on 839.350575, the event ib_cache_event_task was sent andi
queued in ib_wq.

2). In the link [1],

"
team0 (unregistering): Port device team_slave_0 removed
"

It indicates that before 843.251853, the net device should be freed.

3). In the link [1],

"
BUG: KASAN: slab-use-after-free in dev_get_flags+0x188/0x1d0
"

This means that on 850.559070, this slab-use-after-free problem occurred.

In all, on 839.350575, the event ib_cache_event_task was sent and queued
in ib_wq,

before 843.251853, the net device veth was freed.

on 850.559070, this event was executed, and the mentioned freed net device
was called. Thus, the above call trace occurred.

[1] https://syzkaller.appspot.com/x/log.txt?x=12e7025f980000

Reported-by: [e-mail]
Closes: https://syzkaller.appspot.com/bug?extid=4b87489410b4efd181bf
Fixes: 8700e3e7c485 ("Soft RoCE driver")
Signed-off-by: Zhu Yanjun <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Leon Romanovsky <[e-mail]>

drivers/infiniband/sw/rxe/rxe.c

···
 /* initialize rxe device parameters */
 static void rxe_init_device_param(struct rxe_dev *rxe)
 {
+	struct net_device *ndev;
+
 	rxe->max_inline_data			= RXE_MAX_INLINE_DATA;
 
 	rxe->attr.vendor_id			= RXE_VENDOR_ID;
···
 	rxe->attr.max_fast_reg_page_list_len	= RXE_MAX_FMR_PAGE_LIST_LEN;
 	rxe->attr.max_pkeys			= RXE_MAX_PKEYS;
 	rxe->attr.local_ca_ack_delay		= RXE_LOCAL_CA_ACK_DELAY;
+
+	ndev = rxe_ib_device_get_netdev(&rxe->ib_dev);
+	if (!ndev)
+		return;
+
 	addrconf_addr_eui48((unsigned char *)&rxe->attr.sys_image_guid,
-			rxe->ndev->dev_addr);
+			ndev->dev_addr);
+
+	dev_put(ndev);
 
 	rxe->max_ucontext			= RXE_MAX_UCONTEXT;
 }
···
 static void rxe_init_ports(struct rxe_dev *rxe)
 {
 	struct rxe_port *port = &rxe->port;
+	struct net_device *ndev;
 
 	rxe_init_port_param(port);
+	ndev = rxe_ib_device_get_netdev(&rxe->ib_dev);
+	if (!ndev)
+		return;
 	addrconf_addr_eui48((unsigned char *)&port->port_guid,
-			    rxe->ndev->dev_addr);
+			    ndev->dev_addr);
+	dev_put(ndev);
 	spin_lock_init(&port->port_lock);
 }
 
···
 /* called by ifc layer to create new rxe device.
  * The caller should allocate memory for rxe by calling ib_alloc_device.
  */
-int rxe_add(struct rxe_dev *rxe, unsigned int mtu, const char *ibdev_name)
+int rxe_add(struct rxe_dev *rxe, unsigned int mtu, const char *ibdev_name,
+			struct net_device *ndev)
 {
 	rxe_init(rxe);
 	rxe_set_mtu(rxe, mtu);
 
-	return rxe_register_device(rxe, ibdev_name);
+	return rxe_register_device(rxe, ibdev_name, ndev);
 }
 
 static int rxe_newlink(const char *ibdev_name, struct net_device *ndev)

drivers/infiniband/sw/rxe/rxe.h

···
 
 void rxe_set_mtu(struct rxe_dev *rxe, unsigned int dev_mtu);
 
-int rxe_add(struct rxe_dev *rxe, unsigned int mtu, const char *ibdev_name);
+int rxe_add(struct rxe_dev *rxe, unsigned int mtu, const char *ibdev_name,
+			struct net_device *ndev);
 
 void rxe_rcv(struct sk_buff *skb);
 

drivers/infiniband/sw/rxe/rxe_mcast.c

···
 static int rxe_mcast_add(struct rxe_dev *rxe, union ib_gid *mgid)
 {
 	unsigned char ll_addr[ETH_ALEN];
+	struct net_device *ndev;
+	int ret;
+
+	ndev = rxe_ib_device_get_netdev(&rxe->ib_dev);
+	if (!ndev)
+		return -ENODEV;
 
 	ipv6_eth_mc_map((struct in6_addr *)mgid->raw, ll_addr);
 
-	return dev_mc_add(rxe->ndev, ll_addr);
+	ret = dev_mc_add(ndev, ll_addr);
+	dev_put(ndev);
+
+	return ret;
 }
 
 /**
···
 static int rxe_mcast_del(struct rxe_dev *rxe, union ib_gid *mgid)
 {
 	unsigned char ll_addr[ETH_ALEN];
+	struct net_device *ndev;
+	int ret;
+
+	ndev = rxe_ib_device_get_netdev(&rxe->ib_dev);
+	if (!ndev)
+		return -ENODEV;
 
 	ipv6_eth_mc_map((struct in6_addr *)mgid->raw, ll_addr);
 
-	return dev_mc_del(rxe->ndev, ll_addr);
+	ret = dev_mc_del(ndev, ll_addr);
+	dev_put(ndev);
+
+	return ret;
 }
 
 /**

drivers/infiniband/sw/rxe/rxe_net.c

···
  */
 const char *rxe_parent_name(struct rxe_dev *rxe, unsigned int port_num)
 {
-	return rxe->ndev->name;
+	struct net_device *ndev;
+	char *ndev_name;
+
+	ndev = rxe_ib_device_get_netdev(&rxe->ib_dev);
+	if (!ndev)
+		return NULL;
+	ndev_name = ndev->name;
+	dev_put(ndev);
+
+	return ndev_name;
 }
 
 int rxe_net_add(const char *ibdev_name, struct net_device *ndev)
···
 	if (!rxe)
 		return -ENOMEM;
 
-	rxe->ndev = ndev;
 	ib_mark_name_assigned_by_user(&rxe->ib_dev);
 
-	err = rxe_add(rxe, ndev->mtu, ibdev_name);
+	err = rxe_add(rxe, ndev->mtu, ibdev_name, ndev);
 	if (err) {
 		ib_dealloc_device(&rxe->ib_dev);
 		return err;
···
 
 void rxe_set_port_state(struct rxe_dev *rxe)
 {
-	if (netif_running(rxe->ndev) && netif_carrier_ok(rxe->ndev))
+	struct net_device *ndev;
+
+	ndev = rxe_ib_device_get_netdev(&rxe->ib_dev);
+	if (!ndev)
+		return;
+
+	if (netif_running(ndev) && netif_carrier_ok(ndev))
 		rxe_port_up(rxe);
 	else
 		rxe_port_down(rxe);
+
+	dev_put(ndev);
 }
 
 static int rxe_notify(struct notifier_block *not_blk,

drivers/infiniband/sw/rxe/rxe_verbs.c

···
 			  u32 port_num, struct ib_port_attr *attr)
 {
 	struct rxe_dev *rxe = to_rdev(ibdev);
+	struct net_device *ndev;
 	int err, ret;
 
 	if (port_num != 1) {
 		err = -EINVAL;
 		rxe_dbg_dev(rxe, "bad port_num = %d\n", port_num);
+		goto err_out;
+	}
+
+	ndev = rxe_ib_device_get_netdev(ibdev);
+	if (!ndev) {
+		err = -ENODEV;
 		goto err_out;
 	}
 
···
 
 	if (attr->state == IB_PORT_ACTIVE)
 		attr->phys_state = IB_PORT_PHYS_STATE_LINK_UP;
-	else if (dev_get_flags(rxe->ndev) & IFF_UP)
+	else if (dev_get_flags(ndev) & IFF_UP)
 		attr->phys_state = IB_PORT_PHYS_STATE_POLLING;
 	else
 		attr->phys_state = IB_PORT_PHYS_STATE_DISABLED;
 
 	mutex_unlock(&rxe->usdev_lock);
 
+	dev_put(ndev);
 	return ret;
 
 err_out:
···
 static int rxe_enable_driver(struct ib_device *ib_dev)
 {
 	struct rxe_dev *rxe = container_of(ib_dev, struct rxe_dev, ib_dev);
+	struct net_device *ndev;
+
+	ndev = rxe_ib_device_get_netdev(ib_dev);
+	if (!ndev)
+		return -ENODEV;
 
 	rxe_set_port_state(rxe);
-	dev_info(&rxe->ib_dev.dev, "added %s\n", netdev_name(rxe->ndev));
+	dev_info(&rxe->ib_dev.dev, "added %s\n", netdev_name(ndev));
+
+	dev_put(ndev);
 	return 0;
 }
 
···
 	INIT_RDMA_OBJ_SIZE(ib_mw, rxe_mw, ibmw),
 };
 
-int rxe_register_device(struct rxe_dev *rxe, const char *ibdev_name)
+int rxe_register_device(struct rxe_dev *rxe, const char *ibdev_name,
+						struct net_device *ndev)
 {
 	int err;
 	struct ib_device *dev = &rxe->ib_dev;
···
 	dev->num_comp_vectors = num_possible_cpus();
 	dev->local_dma_lkey = 0;
 	addrconf_addr_eui48((unsigned char *)&dev->node_guid,
-			    rxe->ndev->dev_addr);
+			    ndev->dev_addr);
 
 	dev->uverbs_cmd_mask |= BIT_ULL(IB_USER_VERBS_CMD_POST_SEND) |
 				BIT_ULL(IB_USER_VERBS_CMD_REQ_NOTIFY_CQ);
 
 	ib_set_device_ops(dev, &rxe_dev_ops);
-	err = ib_device_set_netdev(&rxe->ib_dev, rxe->ndev, 1);
+	err = ib_device_set_netdev(&rxe->ib_dev, ndev, 1);
 	if (err)
 		return err;
 

drivers/infiniband/sw/rxe/rxe_verbs.h

···
 	u32			qp_gsi_index;
 };
 
+#define	RXE_PORT	1
 struct rxe_dev {
 	struct ib_device	ib_dev;
 	struct ib_device_attr	attr;
 	int			max_ucontext;
 	int			max_inline_data;
 	struct mutex	usdev_lock;
-
-	struct net_device	*ndev;
 
 	struct rxe_pool		uc_pool;
 	struct rxe_pool		pd_pool;
···
 	struct rxe_port		port;
 	struct crypto_shash	*tfm;
 };
+
+static inline struct net_device *rxe_ib_device_get_netdev(struct ib_device *dev)
+{
+	return ib_device_get_netdev(dev, RXE_PORT);
+}
 
 static inline void rxe_counter_inc(struct rxe_dev *rxe, enum rxe_counters index)
 {
···
 	return to_rpd(mw->ibmw.pd);
 }
 
-int rxe_register_device(struct rxe_dev *rxe, const char *ibdev_name);
+int rxe_register_device(struct rxe_dev *rxe, const char *ibdev_name,
+						struct net_device *ndev);
 
 #endif /* RXE_VERBS_H */