BUG: sleeping function called from invalid context at kernel/sched/completion.c:90
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] PREEMPT SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 28953 Comm: syz-executor7 Not tainted 4.9.119-g9dc978d #75
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff8801d928c800 task.stack: ffff8801a21a8000
RIP: 0010:[<ffffffff81236bab>]  [<ffffffff81236bab>] __lock_acquire+0xa1b/0x4070 kernel/locking/lockdep.c:3224
RSP: 0018:ffff8801a21af6a0  EFLAGS: 00010006
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000014 RSI: 0000000000000000 RDI: 00000000000000a0
RBP: ffff8801a21af848 R08: 0000000000000001 R09: 0000000000000000
R10: ffff8801d928c800 R11: 0000000000000001 R12: 0000000000000001
R13: 0000000000000000 R14: 00000000000000a0 R15: 0000000000000000
FS:  00007f796f9cc700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2c123000 CR3: 00000001d3ef9000 CR4: 00000000001606f0
Stack:
 dffffc0000000000 ffffffff85baa4c8 0000000000000282 ffff8801a21af6d8
 ffffffff812358f6 0000000000000286 ffffffff85baa4c8 ffff8801a21af6e8
 0000000000000286 ffff8801a21af708 ffffffff839fc3b5 0000000000017700
Call Trace:
 [<ffffffff8123ac70>] lock_acquire+0x130/0x3e0 kernel/locking/lockdep.c:3756
 [<ffffffff839fc066>] __raw_spin_lock include/linux/spinlock_api_smp.h:144 [inline]
 [<ffffffff839fc066>] _raw_spin_lock+0x36/0x50 kernel/locking/spinlock.c:151
 [<ffffffff836bec8b>] spin_lock include/linux/spinlock.h:302 [inline]
 [<ffffffff836bec8b>] l2tp_xmit_skb+0x38b/0xf60 net/l2tp/l2tp_core.c:1233
 [<ffffffff836cab40>] pppol2tp_sendmsg+0x4e0/0x790 net/l2tp/l2tp_ppp.c:339
 [<ffffffff83018fcc>] sock_sendmsg_nosec net/socket.c:636 [inline]
 [<ffffffff83018fcc>] sock_sendmsg+0xcc/0x110 net/socket.c:646
 [<ffffffff8301a7ea>] ___sys_sendmsg+0x47a/0x840 net/socket.c:1970
 [<ffffffff8301cd41>] __sys_sendmmsg+0x161/0x3d0 net/socket.c:2060
 [<ffffffff8301cfe5>] SYSC_sendmmsg net/socket.c:2091 [inline]
 [<ffffffff8301cfe5>] SyS_sendmmsg+0x35/0x60 net/socket.c:2086
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839fccd3>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb
Code: 25 28 00 00 00 0f 85 17 27 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 51 27 00 00 49 81 3e a0 8c e9 84 0f 84 08 f7 
RIP  [<ffffffff81236bab>] __lock_acquire+0xa1b/0x4070 kernel/locking/lockdep.c:3224
 RSP <ffff8801a21af6a0>
---[ end trace 832675621468a2eb ]---