Re: memory leak in vhost_net_ioctl

[Jeremy Sowden]

On 2019-06-13, at 20:04:01 -0700, syzbot wrote:
> syzbot has tested the proposed patch but the reproducer still
> triggered crash: memory leak in batadv_tvlv_handler_register

There's already a fix for this batman leak:

  https://lore.kernel.org/netdev/00000000000017d64c058965f966@xxxxxxxxxx/
  https://www.open-mesh.org/issues/378

>   484.626788][  T156] bond0 (unregistering): Releasing backup
>   interface bond_slave_1
> Warning: Permanently added '10.128.0.87' (ECDSA) to the list of known
> hosts.
> BUG: memory leak
> unreferenced object 0xffff88811d25c4c0 (size 64):
>   comm "softirq", pid 0, jiffies 4294943668 (age 434.830s)
>   hex dump (first 32 bytes):
>     00 00 00 00 00 00 00 00 e0 fc 5b 20 81 88 ff ff  ..........[ ....
>     00 00 00 00 00 00 00 00 20 91 15 83 ff ff ff ff  ........ .......
>   backtrace:
>     [<000000000045bc9d>] kmemleak_alloc_recursive
> include/linux/kmemleak.h:43 [inline]
>     [<000000000045bc9d>] slab_post_alloc_hook mm/slab.h:439 [inline]
>     [<000000000045bc9d>] slab_alloc mm/slab.c:3326 [inline]
>     [<000000000045bc9d>] kmem_cache_alloc_trace+0x13d/0x280
> mm/slab.c:3553
>     [<00000000197d773e>] kmalloc include/linux/slab.h:547 [inline]
>     [<00000000197d773e>] kzalloc include/linux/slab.h:742 [inline]
>     [<00000000197d773e>] batadv_tvlv_handler_register+0xae/0x140
> net/batman-adv/tvlv.c:529
>     [<00000000fa9f11af>] batadv_tt_init+0x78/0x180
> net/batman-adv/translation-table.c:4411
>     [<000000008c50839d>] batadv_mesh_init+0x196/0x230
> net/batman-adv/main.c:208
>     [<000000001c5a74a3>] batadv_softif_init_late+0x1ca/0x220
> net/batman-adv/soft-interface.c:861
>     [<000000004e676cd1>] register_netdevice+0xbf/0x600
> net/core/dev.c:8635
>     [<000000005601497b>] __rtnl_newlink+0xaca/0xb30
> net/core/rtnetlink.c:3199
>     [<00000000ad02cf5e>] rtnl_newlink+0x4e/0x80
> net/core/rtnetlink.c:3245
>     [<00000000eceb53af>] rtnetlink_rcv_msg+0x178/0x4b0
> net/core/rtnetlink.c:5214
>     [<00000000140451f6>] netlink_rcv_skb+0x61/0x170
> net/netlink/af_netlink.c:2482
>     [<00000000237e38f7>] rtnetlink_rcv+0x1d/0x30
> net/core/rtnetlink.c:5232
>     [<000000000d47c000>] netlink_unicast_kernel
> net/netlink/af_netlink.c:1307 [inline]
>     [<000000000d47c000>] netlink_unicast+0x1ec/0x2d0
> net/netlink/af_netlink.c:1333
>     [<0000000098503d79>] netlink_sendmsg+0x26a/0x480
> net/netlink/af_netlink.c:1922
>     [<000000009263e868>] sock_sendmsg_nosec net/socket.c:646 [inline]
>     [<000000009263e868>] sock_sendmsg+0x54/0x70 net/socket.c:665
>     [<000000007791ad47>] __sys_sendto+0x148/0x1f0 net/socket.c:1958
>     [<00000000d6f3807d>] __do_sys_sendto net/socket.c:1970 [inline]
>     [<00000000d6f3807d>] __se_sys_sendto net/socket.c:1966 [inline]
>     [<00000000d6f3807d>] __x64_sys_sendto+0x2a/0x30 net/socket.c:1966
>
> BUG: memory leak
> unreferenced object 0xffff8881024a3340 (size 64):
>   comm "softirq", pid 0, jiffies 4294943678 (age 434.730s)
>   hex dump (first 32 bytes):
>     00 00 00 00 00 00 00 00 e0 2c 66 04 81 88 ff ff  .........,f.....
>     00 00 00 00 00 00 00 00 20 91 15 83 ff ff ff ff  ........ .......
>   backtrace:
>     [<000000000045bc9d>] kmemleak_alloc_recursive
> include/linux/kmemleak.h:43 [inline]
>     [<000000000045bc9d>] slab_post_alloc_hook mm/slab.h:439 [inline]
>     [<000000000045bc9d>] slab_alloc mm/slab.c:3326 [inline]
>     [<000000000045bc9d>] kmem_cache_alloc_trace+0x13d/0x280
> mm/slab.c:3553
>     [<00000000197d773e>] kmalloc include/linux/slab.h:547 [inline]
>     [<00000000197d773e>] kzalloc include/linux/slab.h:742 [inline]
>     [<00000000197d773e>] batadv_tvlv_handler_register+0xae/0x140
> net/batman-adv/tvlv.c:529
>     [<00000000fa9f11af>] batadv_tt_init+0x78/0x180
> net/batman-adv/translation-table.c:4411
>     [<000000008c50839d>] batadv_mesh_init+0x196/0x230
> net/batman-adv/main.c:208
>     [<000000001c5a74a3>] batadv_softif_init_late+0x1ca/0x220
> net/batman-adv/soft-interface.c:861
>     [<000000004e676cd1>] register_netdevice+0xbf/0x600
> net/core/dev.c:8635
>     [<000000005601497b>] __rtnl_newlink+0xaca/0xb30
> net/core/rtnetlink.c:3199
>     [<00000000ad02cf5e>] rtnl_newlink+0x4e/0x80
> net/core/rtnetlink.c:3245
>     [<00000000eceb53af>] rtnetlink_rcv_msg+0x178/0x4b0
> net/core/rtnetlink.c:5214
>     [<00000000140451f6>] netlink_rcv_skb+0x61/0x170
> net/netlink/af_netlink.c:2482
>     [<00000000237e38f7>] rtnetlink_rcv+0x1d/0x30
> net/core/rtnetlink.c:5232
>     [<000000000d47c000>] netlink_unicast_kernel
> net/netlink/af_netlink.c:1307 [inline]
>     [<000000000d47c000>] netlink_unicast+0x1ec/0x2d0
> net/netlink/af_netlink.c:1333
>     [<0000000098503d79>] netlink_sendmsg+0x26a/0x480
> net/netlink/af_netlink.c:1922
>     [<000000009263e868>] sock_sendmsg_nosec net/socket.c:646 [inline]
>     [<000000009263e868>] sock_sendmsg+0x54/0x70 net/socket.c:665
>     [<000000007791ad47>] __sys_sendto+0x148/0x1f0 net/socket.c:1958
>     [<00000000d6f3807d>] __do_sys_sendto net/socket.c:1970 [inline]
>     [<00000000d6f3807d>] __se_sys_sendto net/socket.c:1966 [inline]
>     [<00000000d6f3807d>] __x64_sys_sendto+0x2a/0x30 net/socket.c:1966
>
> BUG: memory leak
> unreferenced object 0xffff888108a71b80 (size 128):
>   comm "syz-executor.3", pid 7367, jiffies 4294943696 (age 434.550s)
>   hex dump (first 32 bytes):
>     f0 f8 bf 02 81 88 ff ff f0 f8 bf 02 81 88 ff ff  ................
>     1a dc 77 da 54 a0 be 41 64 20 e9 56 ff ff ff ff  ..w.T..Ad .V....
>   backtrace:
>     [<000000000045bc9d>] kmemleak_alloc_recursive
> include/linux/kmemleak.h:43 [inline]
>     [<000000000045bc9d>] slab_post_alloc_hook mm/slab.h:439 [inline]
>     [<000000000045bc9d>] slab_alloc mm/slab.c:3326 [inline]
>     [<000000000045bc9d>] kmem_cache_alloc_trace+0x13d/0x280
> mm/slab.c:3553
>     [<00000000cc6863ae>] kmalloc include/linux/slab.h:547 [inline]
>     [<00000000cc6863ae>] hsr_create_self_node+0x42/0x150
> net/hsr/hsr_framereg.c:84
>     [<000000000e2bb6b0>] hsr_dev_finalize+0xa4/0x233
> net/hsr/hsr_device.c:441
>     [<000000003b100a4a>] hsr_newlink+0xf3/0x140
> net/hsr/hsr_netlink.c:69
>     [<00000000b5efb0eb>] __rtnl_newlink+0x892/0xb30
> net/core/rtnetlink.c:3187
>     [<00000000ad02cf5e>] rtnl_newlink+0x4e/0x80
> net/core/rtnetlink.c:3245
>     [<00000000eceb53af>] rtnetlink_rcv_msg+0x178/0x4b0
> net/core/rtnetlink.c:5214
>     [<00000000140451f6>] netlink_rcv_skb+0x61/0x170
> net/netlink/af_netlink.c:2482
>     [<00000000237e38f7>] rtnetlink_rcv+0x1d/0x30
> net/core/rtnetlink.c:5232
>     [<000000000d47c000>] netlink_unicast_kernel
> net/netlink/af_netlink.c:1307 [inline]
>     [<000000000d47c000>] netlink_unicast+0x1ec/0x2d0
> net/netlink/af_netlink.c:1333
>     [<0000000098503d79>] netlink_sendmsg+0x26a/0x480
> net/netlink/af_netlink.c:1922
>     [<000000009263e868>] sock_sendmsg_nosec net/socket.c:646 [inline]
>     [<000000009263e868>] sock_sendmsg+0x54/0x70 net/socket.c:665
>     [<000000007791ad47>] __sys_sendto+0x148/0x1f0 net/socket.c:1958
>     [<00000000d6f3807d>] __do_sys_sendto net/socket.c:1970 [inline]
>     [<00000000d6f3807d>] __se_sys_sendto net/socket.c:1966 [inline]
>     [<00000000d6f3807d>] __x64_sys_sendto+0x2a/0x30 net/socket.c:1966
>     [<000000003ba31db7>] do_syscall_64+0x76/0x1a0
> arch/x86/entry/common.c:301
>     [<0000000075c8daad>] entry_SYSCALL_64_after_hwframe+0x44/0xa9
>
> Tested on:
>
> commit:         c11fb13a Merge branch 'for-linus' of git://git.kernel.org/..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=15c8f3b6a00000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=cb38d33cd06d8d48
> compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> patch:          https://syzkaller.appspot.com/x/patch.diff?x=12477101a00000

J.

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