e list of known hosts.
executing program
BUG: memory leak
unreferenced object 0xffff888110802480 (size 64):
  comm "softirq", pid 0, jiffies 4294942768 (age 7.910s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 7f 00 00 01 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000f0836163>] kmemleak_alloc_recursive include/linux/kmemleak.h:55 [inline]
    [<00000000f0836163>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<00000000f0836163>] slab_alloc mm/slab.c:3326 [inline]
    [<00000000f0836163>] kmem_cache_alloc_trace+0x13d/0x280 mm/slab.c:3553
    [<00000000242b83fe>] kmalloc include/linux/slab.h:547 [inline]
    [<00000000242b83fe>] kzalloc include/linux/slab.h:742 [inline]
    [<00000000242b83fe>] ip_mc_add1_src net/ipv4/igmp.c:1961 [inline]
    [<00000000242b83fe>] ip_mc_add_src+0x36b/0x400 net/ipv4/igmp.c:2085
    [<000000005716b4e0>] ip_mc_msfilter+0x22d/0x310 net/ipv4/igmp.c:2475
    [<000000003798bbc3>] do_ip_setsockopt.isra.0+0x1795/0x1930 net/ipv4/ip_sockglue.c:957
    [<0000000044577611>] ip_setsockopt+0x3b/0xb0 net/ipv4/ip_sockglue.c:1246
    [<0000000018319181>] raw_setsockopt+0x84/0xa0 net/ipv4/raw.c:860
    [<000000008794428d>] sock_common_setsockopt+0x38/0x50 net/core/sock.c:3130
    [<000000002155b0d1>] __sys_setsockopt+0x98/0x120 net/socket.c:2078
    [<0000000092ea1e07>] __do_sys_setsockopt net/socket.c:2089 [inline]
    [<0000000092ea1e07>] __se_sys_setsockopt net/socket.c:2086 [inline]
    [<0000000092ea1e07>] __x64_sys_setsockopt+0x26/0x30 net/socket.c:2086
    [<0000000002e25b59>] do_syscall_64+0x76/0x1a0 arch/x86/entry/common.c:301
    [<00000000850b652b>] entry_SYSCALL_64_after_hwframe+0x44/0xa9