memory leak in kobject_set_name_vargs (2)

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    3bfe1fc4 Merge tag 'for-5.3/dm-changes-2' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=130322afa00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=dcfc65ee492509c6
dashboard link: https://syzkaller.appspot.com/bug?extid=ad8ca40ecd77896d51e2
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=135cbed0600000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14dd4e34600000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+ad8ca40ecd77896d51e2@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: memory leak
unreferenced object 0xffff88810cc5d860 (size 32):
  comm "syz-executor938", pid 7153, jiffies 4294945400 (age 8.020s)
  hex dump (first 32 bytes):
    69 70 36 5f 76 74 69 31 00 2f 37 31 35 33 00 00  ip6_vti1./7153..
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<000000000800471f>] kmemleak_alloc_recursive  
/./include/linux/kmemleak.h:43 [inline]
    [<000000000800471f>] slab_post_alloc_hook /mm/slab.h:522 [inline]
    [<000000000800471f>] slab_alloc /mm/slab.c:3319 [inline]
    [<000000000800471f>] __do_kmalloc /mm/slab.c:3653 [inline]
    [<000000000800471f>] __kmalloc_track_caller+0x165/0x300 /mm/slab.c:3670
    [<000000007a2eef8e>] kstrdup+0x3a/0x70 /mm/util.c:53
    [<00000000a309e483>] kstrdup_const+0x48/0x60 /mm/util.c:75
    [<00000000cf8dc39b>] kvasprintf_const+0x7e/0xe0 /lib/kasprintf.c:48
    [<000000005a964730>] kobject_set_name_vargs+0x40/0xe0 /lib/kobject.c:289
    [<00000000e2a9ccdf>] dev_set_name+0x63/0x90 /drivers/base/core.c:1915
    [<000000007bc7b1da>] netdev_register_kobject+0x5a/0x1b0  
/net/core/net-sysfs.c:1727
    [<00000000637b4645>] register_netdevice+0x397/0x600 /net/core/dev.c:8723
    [<0000000038b21fdc>] vti6_tnl_create2+0x47/0xb0 /net/ipv6/ip6_vti.c:189
    [<0000000023231475>] vti6_tnl_create /net/ipv6/ip6_vti.c:229 [inline]
    [<0000000023231475>] vti6_locate /net/ipv6/ip6_vti.c:277 [inline]
    [<0000000023231475>] vti6_locate+0x244/0x2c0 /net/ipv6/ip6_vti.c:255
    [<000000006ebf0a44>] vti6_ioctl+0x17f/0x390 /net/ipv6/ip6_vti.c:802
    [<00000000077406fa>] dev_ifsioc+0x324/0x460 /net/core/dev_ioctl.c:322
    [<00000000465d817c>] dev_ioctl+0x157/0x45e /net/core/dev_ioctl.c:514
    [<00000000e2472af6>] sock_ioctl+0x394/0x480 /net/socket.c:1099
    [<0000000024234c3b>] vfs_ioctl /fs/ioctl.c:46 [inline]
    [<0000000024234c3b>] file_ioctl /fs/ioctl.c:509 [inline]
    [<0000000024234c3b>] do_vfs_ioctl+0x62a/0x810 /fs/ioctl.c:696
    [<0000000015b52ca4>] ksys_ioctl+0x86/0xb0 /fs/ioctl.c:713



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