netdev - Memory leaks in conntrack

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Date:   Tue, 12 Sep 2017 16:20:50 -0700
From:   Cong Wang <xiyou.wangcong@...il.com>
To:     netfilter-devel@...r.kernel.org
Cc:     Linux Kernel Network Developers <netdev@...r.kernel.org>
Subject: Memory leaks in conntrack

Hello,

While testing my TC filter patches (so not related to conntrack), the
following memory leaks are shown up:


unreferenced object 0xffff9b19ba551228 (size 128):
  comm "chronyd", pid 338, jiffies 4294910829 (age 53.188s)
  hex dump (first 32 bytes):
    6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
    00 00 00 00 18 00 00 30 00 00 00 00 00 00 00 00  .......0........
  backtrace:
    [<ffffffff9f1e1175>] create_object+0x169/0x2aa
    [<ffffffff9fb77fb2>] kmemleak_alloc+0x25/0x41
    [<ffffffff9f1c47ed>] slab_post_alloc_hook+0x44/0x65
    [<ffffffff9f1ca2db>] __kmalloc_track_caller+0x113/0x146
    [<ffffffff9f193c3b>] __krealloc+0x4a/0x69
    [<ffffffff9f948dbd>] nf_ct_ext_add+0xe1/0x145
    [<ffffffff9f942395>] init_conntrack+0x1f7/0x36e
    [<ffffffff9f942762>] nf_conntrack_in+0x1d3/0x326
    [<ffffffff9fa1ea69>] ipv4_conntrack_local+0x4d/0x50
    [<ffffffff9f93ad70>] nf_hook_slow+0x3c/0x9b
    [<ffffffff9f9c7999>] nf_hook.constprop.40+0xbe/0xd8
    [<ffffffff9f9c7ba2>] __ip_local_out+0xb3/0xbf
    [<ffffffff9f9c7bca>] ip_local_out+0x1c/0x36
    [<ffffffff9f9c9216>] ip_send_skb+0x19/0x3d
    [<ffffffff9f9ee3de>] udp_send_skb+0x17e/0x1df
    [<ffffffff9f9eea37>] udp_sendmsg+0x5a2/0x77c
unreferenced object 0xffff9b19a69b3340 (size 336):
  comm "chronyd", pid 338, jiffies 4294910868 (age 53.032s)
  hex dump (first 32 bytes):
    01 00 00 00 5a 5a 5a 5a 00 00 00 00 ad 4e ad de  ....ZZZZ.....N..
    ff ff ff ff 5a 5a 5a 5a ff ff ff ff ff ff ff ff  ....ZZZZ........
  backtrace:
    [<ffffffff9f1e1175>] create_object+0x169/0x2aa
    [<ffffffff9fb77fb2>] kmemleak_alloc+0x25/0x41
    [<ffffffff9f1c47ed>] slab_post_alloc_hook+0x44/0x65
    [<ffffffff9f1c7a7d>] kmem_cache_alloc+0xd7/0x1f1
    [<ffffffff9f941b78>] __nf_conntrack_alloc+0xa2/0x146
    [<ffffffff9f942250>] init_conntrack+0xb2/0x36e
    [<ffffffff9f942762>] nf_conntrack_in+0x1d3/0x326
    [<ffffffff9fa1ea69>] ipv4_conntrack_local+0x4d/0x50
    [<ffffffff9f93ad70>] nf_hook_slow+0x3c/0x9b
    [<ffffffff9f9c7999>] nf_hook.constprop.40+0xbe/0xd8
    [<ffffffff9f9c7ba2>] __ip_local_out+0xb3/0xbf
    [<ffffffff9f9c7bca>] ip_local_out+0x1c/0x36
    [<ffffffff9f9c9216>] ip_send_skb+0x19/0x3d
    [<ffffffff9f9ee3de>] udp_send_skb+0x17e/0x1df
    [<ffffffff9f9eea37>] udp_sendmsg+0x5a2/0x77c
    [<ffffffff9f9f8cb8>] inet_sendmsg+0x37/0x5e

This seems new because I never see this before.

I don't touch chronyd in my VM, so I have no idea why it sends out UDP
packets, my guess is it is some periodical packet.

I don't think I use conntrack either, since /proc/net/ip_conntrack
does not exist.

Here are some related config of my kernel:

$ grep CONNTRACK .config
CONFIG_NF_CONNTRACK=y
CONFIG_NF_CONNTRACK_MARK=y
CONFIG_NF_CONNTRACK_SECMARK=y
CONFIG_NF_CONNTRACK_ZONES=y
CONFIG_NF_CONNTRACK_PROCFS=y
CONFIG_NF_CONNTRACK_EVENTS=y
# CONFIG_NF_CONNTRACK_TIMEOUT is not set
CONFIG_NF_CONNTRACK_TIMESTAMP=y
CONFIG_NF_CONNTRACK_AMANDA=y
CONFIG_NF_CONNTRACK_FTP=y
CONFIG_NF_CONNTRACK_H323=y
CONFIG_NF_CONNTRACK_IRC=y
CONFIG_NF_CONNTRACK_BROADCAST=y
CONFIG_NF_CONNTRACK_NETBIOS_NS=y
CONFIG_NF_CONNTRACK_SNMP=y
CONFIG_NF_CONNTRACK_PPTP=y
CONFIG_NF_CONNTRACK_SANE=y
CONFIG_NF_CONNTRACK_SIP=y
CONFIG_NF_CONNTRACK_TFTP=y
CONFIG_NETFILTER_XT_MATCH_CONNTRACK=y
CONFIG_NF_CONNTRACK_IPV4=y
CONFIG_NF_CONNTRACK_IPV6=y

Please let me know if you need any other information.

Thanks.