------------[ cut here ]------------
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 13102 at lib/refcount.c:28 refcount_warn_saturate+0x1dc/0x1f0 lib/refcount.c:28
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 13102 Comm: syz-executor.0 Not tainted 5.5.0-rc1-next-20191213-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x197/0x210 lib/dump_stack.c:118
 panic+0x2e3/0x75c kernel/panic.c:221
 __warn.cold+0x2f/0x3e kernel/panic.c:582
 report_bug+0x289/0x300 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 fixup_bug arch/x86/kernel/traps.c:169 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:267
 do_invalid_op+0x37/0x50 arch/x86/kernel/traps.c:286
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1027
RIP: 0010:refcount_warn_saturate+0x1dc/0x1f0 lib/refcount.c:28
Code: e9 d8 fe ff ff 48 89 df e8 41 31 23 fe e9 85 fe ff ff e8 a7 4e e5 fd 48 c7 c7 20 d8 6f 88 c6 05 75 96 ec 06 01 e8 73 de b5 fd <0f> 0b e9 ac fe ff ff 0f 1f 00 66 2e 0f 1f 84 00 00 00 00 00 55 48
RSP: 0018:ffffc90005577998 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815e8b66 RDI: fffff52000aaef25
RBP: ffffc900055779a8 R08: ffff8880528de400 R09: ffffed1015d06659
R10: ffffed1015d06658 R11: ffff8880ae8332c7 R12: 0000000000000003
R13: ffff888095535e58 R14: ffff888095535e00 R15: ffffffff8a0244c0
 refcount_sub_and_test include/linux/refcount.h:261 [inline]
 refcount_dec_and_test include/linux/refcount.h:281 [inline]
 kref_put include/linux/kref.h:64 [inline]
 put_watch+0xa2/0xb0 drivers/misc/watch_queue.c:633
 watch_queue_clear drivers/misc/watch_queue.c:826 [inline]
 watch_queue_release+0x34b/0xc40 drivers/misc/watch_queue.c:842
 __fput+0x2ff/0x890 fs/file_table.c:280
 ____fput+0x16/0x20 fs/file_table.c:313
 task_work_run+0x145/0x1c0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x909/0x2f20 kernel/exit.c:797
 do_group_exit+0x135/0x360 kernel/exit.c:895
 get_signal+0x47c/0x24f0 kernel/signal.c:2734
 do_signal+0x87/0x1700 arch/x86/kernel/signal.c:815
 exit_to_usermode_loop+0x286/0x380 arch/x86/entry/common.c:160
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x676/0x790 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45a777
Code: 48 83 c4 08 48 89 d8 5b 5d c3 66 0f 1f 84 00 00 00 00 00 48 89 e8 48 f7 d8 48 39 c3 0f 92 c0 eb 92 66 90 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 0d b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ff64732da68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: 0000000000000007 RCX: 000000000045a777
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000006
RBP: 000000000075bf20 R08: 00007ff64732db40 R09: 00007ff64732dae0
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff64732e6d4
R13: 00000000004cae75 R14: 00000000004e4378 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..