kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 2 PID: 3008 Comm: syzkaller007950 Not tainted 4.14.0-rc5-next-20171018+ #8
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88003e3d2140 task.stack: ffff88003d578000
RIP: 0010:__read_once_size include/linux/compiler.h:276 [inline]
RIP: 0010:hrtimer_active+0x211/0x410 kernel/time/hrtimer.c:1142
RSP: 0018:ffff88003d57f3f0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 1ffff10007aafeab RCX: ffffffff815ef89f
RDX: 0000000000000000 RSI: ffffffff85b376a0 RDI: ffff88006ce9f320
RBP: ffff88003d57f530 R08: ffffffff83f9e367 R09: 0000000000000004
R10: ffff88003d57f898 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: ffffed0007aafe89 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff88006de00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020511fd8 CR3: 0000000005a22000 CR4: 00000000000006e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 hrtimer_try_to_cancel+0x91/0x5c0 kernel/time/hrtimer.c:1006
 hrtimer_cancel+0x22/0x40 kernel/time/hrtimer.c:1032
 napi_disable+0x87/0xa0 net/core/dev.c:5552
 tun_napi_disable drivers/net/tun.c:290 [inline]
 __tun_detach+0xe26/0x1570 drivers/net/tun.c:617
 tun_detach drivers/net/tun.c:664 [inline]
 tun_chr_close+0x44/0x60 drivers/net/tun.c:2835
 __fput+0x327/0x7e0 fs/file_table.c:210
 ____fput+0x15/0x20 fs/file_table.c:244
 task_work_run+0x199/0x270 kernel/task_work.c:112
 exit_task_work include/linux/task_work.h:21 [inline]
 do_exit+0x9b5/0x1ad0 kernel/exit.c:869
 do_group_exit+0x149/0x400 kernel/exit.c:972
 SYSC_exit_group kernel/exit.c:983 [inline]
 SyS_exit_group+0x1d/0x20 kernel/exit.c:981
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x437c39
RSP: 002b:00007fffd8d05838 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000437c39
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000082 R08: 000000000000003c R09: 00000000000000e7
R10: ffffffffffffffc0 R11: 0000000000000246 R12: 74656e2f7665642f
R13: 0000000000401cf0 R14: 0000000000401d80 R15: 0000000000000000
Code: c6 00 00 48 8b 85 d8 fe ff ff 48 c1 e8 03 42 80 3c 38 00 0f 85 f2 01 00 00 48 8b 85 e8 fe ff ff 4c 8b 60 30 4c 89 e0 48 c1 e8 03 <42> 80 3c 38 00 0f 85 c8 01 00 00 48 8b 85 f0 fe ff ff 49 8b 1c 
RIP: __read_once_size include/linux/compiler.h:276 [inline] RSP: ffff88003d57f3f0
RIP: hrtimer_active+0x211/0x410 kernel/time/hrtimer.c:1142 RSP: ffff88003d57f3f0
---[ end trace f0d7e3202678b826 ]---