[ovs-dev] [PATCH] net: openvswitch: free vport unless register_netdevice() succeeds

Hillf Danton hdanton at sina.com
Fri Aug 9 03:55:15 UTC 2019


syzbot found the following crash on:

HEAD commit:    1e78030e Merge tag 'mmc-v5.3-rc1' of git://git.kernel.org/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=148d3d1a600000
kernel config:  https://syzkaller.appspot.com/x/.config?x=30cef20daf3e9977
dashboard link: https://syzkaller.appspot.com/bug?extid=13210896153522fe1ee5
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=136aa8c4600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=109ba792600000

=====================================================================
BUG: memory leak
unreferenced object 0xffff8881207e4100 (size 128):
   comm "syz-executor032", pid 7014, jiffies 4294944027 (age 13.830s)
   hex dump (first 32 bytes):
     00 70 16 18 81 88 ff ff 80 af 8c 22 81 88 ff ff  .p........."....
     00 b6 23 17 81 88 ff ff 00 00 00 00 00 00 00 00  ..#.............
   backtrace:
     [<000000000eb78212>] kmemleak_alloc_recursive  include/linux/kmemleak.h:43 [inline]
     [<000000000eb78212>] slab_post_alloc_hook mm/slab.h:522 [inline]
     [<000000000eb78212>] slab_alloc mm/slab.c:3319 [inline]
     [<000000000eb78212>] kmem_cache_alloc_trace+0x145/0x2c0 mm/slab.c:3548
     [<00000000006ea6c6>] kmalloc include/linux/slab.h:552 [inline]
     [<00000000006ea6c6>] kzalloc include/linux/slab.h:748 [inline]
     [<00000000006ea6c6>] ovs_vport_alloc+0x37/0xf0  net/openvswitch/vport.c:130
     [<00000000f9a04a7d>] internal_dev_create+0x24/0x1d0  net/openvswitch/vport-internal_dev.c:164
     [<0000000056ee7c13>] ovs_vport_add+0x81/0x190  net/openvswitch/vport.c:199
     [<000000005434efc7>] new_vport+0x19/0x80 net/openvswitch/datapath.c:194
     [<00000000b7b253f1>] ovs_dp_cmd_new+0x22f/0x410  net/openvswitch/datapath.c:1614
     [<00000000e0988518>] genl_family_rcv_msg+0x2ab/0x5b0  net/netlink/genetlink.c:629
     [<00000000d0cc9347>] genl_rcv_msg+0x54/0x9c net/netlink/genetlink.c:654
     [<000000006694b647>] netlink_rcv_skb+0x61/0x170  net/netlink/af_netlink.c:2477
     [<0000000088381f37>] genl_rcv+0x29/0x40 net/netlink/genetlink.c:665
     [<00000000dad42a47>] netlink_unicast_kernel  net/netlink/af_netlink.c:1302 [inline]
     [<00000000dad42a47>] netlink_unicast+0x1ec/0x2d0  net/netlink/af_netlink.c:1328
     [<0000000067e6b079>] netlink_sendmsg+0x270/0x480  net/netlink/af_netlink.c:1917
     [<00000000aab08a47>] sock_sendmsg_nosec net/socket.c:637 [inline]
     [<00000000aab08a47>] sock_sendmsg+0x54/0x70 net/socket.c:657
     [<000000004cb7c11d>] ___sys_sendmsg+0x393/0x3c0 net/socket.c:2311
     [<00000000c4901c63>] __sys_sendmsg+0x80/0xf0 net/socket.c:2356
     [<00000000c10abb2d>] __do_sys_sendmsg net/socket.c:2365 [inline]
     [<00000000c10abb2d>] __se_sys_sendmsg net/socket.c:2363 [inline]
     [<00000000c10abb2d>] __x64_sys_sendmsg+0x23/0x30 net/socket.c:2363

BUG: memory leak
unreferenced object 0xffff88811723b600 (size 64):
   comm "syz-executor032", pid 7014, jiffies 4294944027 (age 13.830s)
   hex dump (first 32 bytes):
     01 00 00 00 01 00 00 00 00 00 00 00 00 00 00 00  ................
     00 00 00 00 00 00 00 00 02 00 00 00 05 35 82 c1  .............5..
   backtrace:
     [<00000000352f46d8>] kmemleak_alloc_recursive  include/linux/kmemleak.h:43 [inline]
     [<00000000352f46d8>] slab_post_alloc_hook mm/slab.h:522 [inline]
     [<00000000352f46d8>] slab_alloc mm/slab.c:3319 [inline]
     [<00000000352f46d8>] __do_kmalloc mm/slab.c:3653 [inline]
     [<00000000352f46d8>] __kmalloc+0x169/0x300 mm/slab.c:3664
     [<000000008e48f3d1>] kmalloc include/linux/slab.h:557 [inline]
     [<000000008e48f3d1>] ovs_vport_set_upcall_portids+0x54/0xd0  net/openvswitch/vport.c:343
     [<00000000541e4f4a>] ovs_vport_alloc+0x7f/0xf0  net/openvswitch/vport.c:139
     [<00000000f9a04a7d>] internal_dev_create+0x24/0x1d0  net/openvswitch/vport-internal_dev.c:164
     [<0000000056ee7c13>] ovs_vport_add+0x81/0x190  net/openvswitch/vport.c:199
     [<000000005434efc7>] new_vport+0x19/0x80 net/openvswitch/datapath.c:194
     [<00000000b7b253f1>] ovs_dp_cmd_new+0x22f/0x410  net/openvswitch/datapath.c:1614
     [<00000000e0988518>] genl_family_rcv_msg+0x2ab/0x5b0  net/netlink/genetlink.c:629
     [<00000000d0cc9347>] genl_rcv_msg+0x54/0x9c net/netlink/genetlink.c:654
     [<000000006694b647>] netlink_rcv_skb+0x61/0x170  net/netlink/af_netlink.c:2477
     [<0000000088381f37>] genl_rcv+0x29/0x40 net/netlink/genetlink.c:665
     [<00000000dad42a47>] netlink_unicast_kernel  net/netlink/af_netlink.c:1302 [inline]
     [<00000000dad42a47>] netlink_unicast+0x1ec/0x2d0  net/netlink/af_netlink.c:1328
     [<0000000067e6b079>] netlink_sendmsg+0x270/0x480  net/netlink/af_netlink.c:1917
     [<00000000aab08a47>] sock_sendmsg_nosec net/socket.c:637 [inline]
     [<00000000aab08a47>] sock_sendmsg+0x54/0x70 net/socket.c:657
     [<000000004cb7c11d>] ___sys_sendmsg+0x393/0x3c0 net/socket.c:2311
     [<00000000c4901c63>] __sys_sendmsg+0x80/0xf0 net/socket.c:2356

BUG: memory leak
unreferenced object 0xffff8881228ca500 (size 128):
   comm "syz-executor032", pid 7015, jiffies 4294944622 (age 7.880s)
   hex dump (first 32 bytes):
     00 f0 27 18 81 88 ff ff 80 ac 8c 22 81 88 ff ff  ..'........"....
     40 b7 23 17 81 88 ff ff 00 00 00 00 00 00 00 00  @.#.............
   backtrace:
     [<000000000eb78212>] kmemleak_alloc_recursive  include/linux/kmemleak.h:43 [inline]
     [<000000000eb78212>] slab_post_alloc_hook mm/slab.h:522 [inline]
     [<000000000eb78212>] slab_alloc mm/slab.c:3319 [inline]
     [<000000000eb78212>] kmem_cache_alloc_trace+0x145/0x2c0 mm/slab.c:3548
     [<00000000006ea6c6>] kmalloc include/linux/slab.h:552 [inline]
     [<00000000006ea6c6>] kzalloc include/linux/slab.h:748 [inline]
     [<00000000006ea6c6>] ovs_vport_alloc+0x37/0xf0  net/openvswitch/vport.c:130
     [<00000000f9a04a7d>] internal_dev_create+0x24/0x1d0  net/openvswitch/vport-internal_dev.c:164
     [<0000000056ee7c13>] ovs_vport_add+0x81/0x190  net/openvswitch/vport.c:199
     [<000000005434efc7>] new_vport+0x19/0x80 net/openvswitch/datapath.c:194
     [<00000000b7b253f1>] ovs_dp_cmd_new+0x22f/0x410  net/openvswitch/datapath.c:1614
     [<00000000e0988518>] genl_family_rcv_msg+0x2ab/0x5b0  net/netlink/genetlink.c:629
     [<00000000d0cc9347>] genl_rcv_msg+0x54/0x9c net/netlink/genetlink.c:654
     [<000000006694b647>] netlink_rcv_skb+0x61/0x170  net/netlink/af_netlink.c:2477
     [<0000000088381f37>] genl_rcv+0x29/0x40 net/netlink/genetlink.c:665
     [<00000000dad42a47>] netlink_unicast_kernel  net/netlink/af_netlink.c:1302 [inline]
     [<00000000dad42a47>] netlink_unicast+0x1ec/0x2d0  net/netlink/af_netlink.c:1328
     [<0000000067e6b079>] netlink_sendmsg+0x270/0x480  net/netlink/af_netlink.c:1917
     [<00000000aab08a47>] sock_sendmsg_nosec net/socket.c:637 [inline]
     [<00000000aab08a47>] sock_sendmsg+0x54/0x70 net/socket.c:657
     [<000000004cb7c11d>] ___sys_sendmsg+0x393/0x3c0 net/socket.c:2311
     [<00000000c4901c63>] __sys_sendmsg+0x80/0xf0 net/socket.c:2356
     [<00000000c10abb2d>] __do_sys_sendmsg net/socket.c:2365 [inline]
     [<00000000c10abb2d>] __se_sys_sendmsg net/socket.c:2363 [inline]
     [<00000000c10abb2d>] __x64_sys_sendmsg+0x23/0x30 net/socket.c:2363
=====================================================================

The function in net core, register_netdevice(), may fail with vport's
destruction callback either invoked or not. After commit 309b66970ee2,
the duty to destroy vport is offloaded from the driver OTOH, which ends
up in the memory leak reported.

It is fixed by releasing vport unless device is registered successfully.
To do that, the callback assignment is defered until device is registered.

Reported-by: syzbot+13210896153522fe1ee5 at syzkaller.appspotmail.com
Fixes: 309b66970ee2 ("net: openvswitch: do not free vport if register_netdevice() is failed.")
Cc: Taehee Yoo <ap420073 at gmail.com>
Cc: Greg Rose <gvrose8192 at gmail.com>
Cc: Eric Dumazet <eric.dumazet at gmail.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner at gmail.com>
Cc: Ying Xue <ying.xue at windriver.com>
Cc: Andrey Konovalov <andreyknvl at google.com>
Signed-off-by: Hillf Danton <hdanton at sina.com>
---

--- a/net/openvswitch/vport-internal_dev.c
+++ b/net/openvswitch/vport-internal_dev.c
@@ -137,7 +137,7 @@ static void do_setup(struct net_device *
 	netdev->priv_flags |= IFF_LIVE_ADDR_CHANGE | IFF_OPENVSWITCH |
 			      IFF_NO_QUEUE;
 	netdev->needs_free_netdev = true;
-	netdev->priv_destructor = internal_dev_destructor;
+	netdev->priv_destructor = NULL;
 	netdev->ethtool_ops = &internal_dev_ethtool_ops;
 	netdev->rtnl_link_ops = &internal_dev_link_ops;
 
@@ -159,7 +159,6 @@ static struct vport *internal_dev_create
 	struct internal_dev *internal_dev;
 	struct net_device *dev;
 	int err;
-	bool free_vport = true;
 
 	vport = ovs_vport_alloc(0, &ovs_internal_vport_ops, parms);
 	if (IS_ERR(vport)) {
@@ -190,10 +189,9 @@ static struct vport *internal_dev_create
 
 	rtnl_lock();
 	err = register_netdevice(vport->dev);
-	if (err) {
-		free_vport = false;
+	if (err)
 		goto error_unlock;
-	}
+	vport->dev->priv_destructor = internal_dev_destructor;
 
 	dev_set_promiscuity(vport->dev, 1);
 	rtnl_unlock();
@@ -207,8 +205,7 @@ error_unlock:
 error_free_netdev:
 	free_netdev(dev);
 error_free_vport:
-	if (free_vport)
-		ovs_vport_free(vport);
+	ovs_vport_free(vport);
 error:
 	return ERR_PTR(err);
 }
--



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