memory leak in llc_ui_sendmsg

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    f49aa1de Merge tag 'for-5.2-rc1-tag' of git://git.kernel.o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=117ba18aa00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=61dd9e15a761691d
dashboard link: https://syzkaller.appspot.com/bug?extid=31c16aa4202dace3812e
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=137f3d9ca00000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=156389f8a00000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+31c16aa4202dace3812e@xxxxxxxxxxxxxxxxxxxxxxxxx

udit(1558395599.193:36): avc:  denied  { map } for  pid=7045  
comm="syz-executor641" path="/root/syz-executor641959542" dev="sda1"  
ino=1426 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023  
tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1
executing program
executing program
executing program
BUG: memory leak
unreferenced object 0xffff888116270800 (size 224):
  comm "syz-executor641", pid 7047, jiffies 4294947360 (age 13.860s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 20 e1 2a 81 88 ff ff 00 40 3d 2a 81 88 ff ff  . .*.....@=*....
  backtrace:
    [<000000004d41b4cc>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:55 [inline]
    [<000000004d41b4cc>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<000000004d41b4cc>] slab_alloc_node mm/slab.c:3269 [inline]
    [<000000004d41b4cc>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579
    [<00000000506a5965>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:198
    [<000000001ba5a161>] alloc_skb include/linux/skbuff.h:1058 [inline]
    [<000000001ba5a161>] alloc_skb_with_frags+0x5f/0x250  
net/core/skbuff.c:5327
    [<0000000047d9c78b>] sock_alloc_send_pskb+0x269/0x2a0  
net/core/sock.c:2225
    [<000000003828fe54>] sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2242
    [<00000000e34d94f9>] llc_ui_sendmsg+0x10a/0x540 net/llc/af_llc.c:933
    [<00000000de2de3fb>] sock_sendmsg_nosec net/socket.c:652 [inline]
    [<00000000de2de3fb>] sock_sendmsg+0x54/0x70 net/socket.c:671
    [<000000008fe16e7a>] __sys_sendto+0x148/0x1f0 net/socket.c:1964
    [<000000005b17a3ac>] __do_sys_sendto net/socket.c:1976 [inline]
    [<000000005b17a3ac>] __se_sys_sendto net/socket.c:1972 [inline]
    [<000000005b17a3ac>] __x64_sys_sendto+0x2a/0x30 net/socket.c:1972
    [<0000000094b2fa53>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:301
    [<00000000ea5a7233>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

BUG: memory leak
unreferenced object 0xffff88812274ac00 (size 512):
  comm "syz-executor641", pid 7047, jiffies 4294947360 (age 13.860s)
  hex dump (first 32 bytes):
    08 c2 03 00 00 00 00 00 69 63 65 73 2f 76 69 72  ........ices/vir
    74 75 61 6c 2f 74 74 79 2f 74 74 79 71 37 00 41  tual/tty/ttyq7.A
  backtrace:
    [<000000009abfb07f>] kmemleak_alloc_recursive  
include/linux/kmemleak.h:55 [inline]
    [<000000009abfb07f>] slab_post_alloc_hook mm/slab.h:439 [inline]
    [<000000009abfb07f>] slab_alloc_node mm/slab.c:3269 [inline]
    [<000000009abfb07f>] kmem_cache_alloc_node_trace+0x15b/0x2a0  
mm/slab.c:3597
    [<000000001e6bdec9>] __do_kmalloc_node mm/slab.c:3619 [inline]
    [<000000001e6bdec9>] __kmalloc_node_track_caller+0x38/0x50  
mm/slab.c:3634
    [<00000000dcf4f208>] __kmalloc_reserve.isra.0+0x40/0xb0  
net/core/skbuff.c:142
    [<0000000081158459>] __alloc_skb+0xa0/0x210 net/core/skbuff.c:210
    [<000000001ba5a161>] alloc_skb include/linux/skbuff.h:1058 [inline]
    [<000000001ba5a161>] alloc_skb_with_frags+0x5f/0x250  
net/core/skbuff.c:5327
    [<0000000047d9c78b>] sock_alloc_send_pskb+0x269/0x2a0  
net/core/sock.c:2225
    [<000000003828fe54>] sock_alloc_send_skb+0x32/0x40 net/core/sock.c:2242
    [<00000000e34d94f9>] llc_ui_sendmsg+0x10a/0x540 net/llc/af_llc.c:933
    [<00000000de2de3fb>] sock_sendmsg_nosec net/socket.c:652 [inline]
    [<00000000de2de3fb>] sock_sendmsg+0x54/0x70 net/socket.c:671
    [<000000008fe16e7a>] __sys_sendto+0x148/0x1f0 net/socket.c:1964
    [<000000005b17a3ac>] __do_sys_sendto net/socket.c:1976 [inline]
    [<000000005b17a3ac>] __se_sys_sendto net/socket.c:1972 [inline]
    [<000000005b17a3ac>] __x64_sys_sendto+0x2a/0x30 net/socket.c:1972
    [<0000000094b2fa53>] do_syscall_64+0x76/0x1a0  
arch/x86/entry/common.c:301
    [<00000000ea5a7233>] entry_SYSCALL_64_after_hwframe+0x44/0xa9

executing program
executing program


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxxx

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this bug, for details see:
https://goo.gl/tpsmEJ#testing-patches