input: syz1 as /devices/virtual/input/input1201
------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 11568 at lib/refcount.c:25 refcount_warn_saturate+0x174/0x1f0 lib/refcount.c:25
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 11568 Comm: syz-executor536 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+0x174/0x1f0 lib/refcount.c:25
Code: 06 31 ff 89 de e8 5c 50 e5 fd 84 db 0f 85 33 ff ff ff e8 0f 4f e5 fd 48 c7 c7 c0 d7 6f 88 c6 05 de 96 ec 06 01 e8 db de b5 fd <0f> 0b e9 14 ff ff ff e8 f0 4e e5 fd 0f b6 1d c3 96 ec 06 31 ff 89
RSP: 0018:ffffc90004047808 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff815e8b66 RDI: fffff52000808ef3
RBP: ffffc90004047818 R08: ffff8880963f2440 R09: fffffbfff165a7b1
R10: fffffbfff165a7b0 R11: ffffffff8b2d3d87 R12: 0000000000000002
R13: ffff888093eea660 R14: ffff8880a69d2c80 R15: ffff88808b125f28
 refcount_add include/linux/refcount.h:191 [inline]
 refcount_inc include/linux/refcount.h:228 [inline]
 kref_get include/linux/kref.h:45 [inline]
 kobject_get+0x134/0x150 lib/kobject.c:644
 cdev_get+0x60/0xb0 fs/char_dev.c:355
 chrdev_open+0xb0/0x6b0 fs/char_dev.c:400
 do_dentry_open+0x4ca/0x1350 fs/open.c:797
 vfs_open+0xa0/0xd0 fs/open.c:914
 do_last fs/namei.c:3551 [inline]
 path_openat+0x12fd/0x34d0 fs/namei.c:3668
 do_filp_open+0x192/0x260 fs/namei.c:3698
 do_sys_openat2+0x633/0x840 fs/open.c:1152
 do_sys_open+0xfc/0x190 fs/open.c:1168
 ksys_open include/linux/syscalls.h:1389 [inline]
 __do_sys_open fs/open.c:1174 [inline]
 __se_sys_open fs/open.c:1172 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1172
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x401480
Code: 01 f0 ff ff 0f 83 c0 0b 00 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 83 3d 4d 62 2d 00 00 75 14 b8 02 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 94 0b 00 00 c3 48 83 ec 08 e8 fa 00 00 00
RSP: 002b:00007ffed888bcf8 EFLAGS: 00000246 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000401480
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007ffed888bd00
RBP: 6666666666666667 R08: 000000000000000f R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000000000c7
R13: 0000000000402530 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..