memory leak in genl_register_family

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    4b972a01 Linux 5.2-rc6
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1305b385a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=1db8bd6825f9661c
dashboard link: https://syzkaller.appspot.com/bug?extid=fc577f12f25f2ac3b211
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=15bd1385a00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+fc577f12f25f2ac3b211@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: memory leak
unreferenced object 0xffff88812a7f0c80 (size 64):
  comm "swapper/0", pid 1, jiffies 4294937561 (age 881.930s)
  hex dump (first 32 bytes):
    2f 64 65 76 69 63 65 73 2f 76 69 72 74 75 61 6c  /devices/virtual
    2f 6e 65 74 2f 6c 6f 2f 71 75 65 75 65 73 2f 74  /net/lo/queues/t
  backtrace:
    [<00000000d629f5fa>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:43 [inline]
    [<00000000d629f5fa>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<00000000d629f5fa>] slab_alloc mm/slab.c:3326 [inline]
    [<00000000d629f5fa>] __do_kmalloc mm/slab.c:3658 [inline]
    [<00000000d629f5fa>] __kmalloc+0x161/0x2c0 mm/slab.c:3669
    [<000000003291d450>] kmalloc_array include/linux/slab.h:670 [inline]
    [<000000003291d450>] genl_register_family net/netlink/genetlink.c:355  
[inline]
    [<000000003291d450>] genl_register_family+0x5e1/0x7e0  
net/netlink/genetlink.c:322
    [<00000000f8e2dd0d>] netlbl_unlabel_genl_init+0x15/0x17  
net/netlabel/netlabel_unlabeled.c:1387
    [<00000000189b4a0c>] netlbl_netlink_init+0x39/0x46  
net/netlabel/netlabel_user.c:65
    [<0000000083adc8f0>] netlbl_init+0x65/0xa8  
net/netlabel/netlabel_kapi.c:1502
    [<000000003a053024>] do_one_initcall+0x5c/0x2ca init/main.c:915
    [<00000000d70991fc>] do_initcall_level init/main.c:983 [inline]
    [<00000000d70991fc>] do_initcalls init/main.c:991 [inline]
    [<00000000d70991fc>] do_basic_setup init/main.c:1009 [inline]
    [<00000000d70991fc>] kernel_init_freeable+0x1af/0x26c init/main.c:1169
    [<00000000232b80c4>] kernel_init+0x10/0x155 init/main.c:1087
    [<000000006b3bb174>] ret_from_fork+0x1f/0x30  
arch/x86/entry/entry_64.S:352



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