------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 30911 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: 30911 Comm: syz-executor.5 Not tainted 5.5.0-rc1-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 ec ea e5 fd 84 db 0f 85 33 ff ff ff e8 9f e9 e5 fd 48 c7 c7 e0 c6 6f 88 c6 05 02 d0 e5 06 01 e8 5b 93 b6 fd <0f> 0b e9 14 ff ff ff e8 80 e9 e5 fd 0f b6 1d e7 cf e5 06 31 ff 89
RSP: 0018:ffffc9000830f8a8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 000000000001067b RSI: ffffffff815e88f6 RDI: fffff52001061f07
RBP: ffffc9000830f8b8 R08: ffff8880536d4140 R09: fffffbfff1659db1
R10: fffffbfff1659db0 R11: ffffffff8b2ced87 R12: 0000000000000002
R13: ffff888055f29660 R14: ffff88809960fa00 R15: ffff888096405f28
 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+0x4e6/0x1380 fs/open.c:797
 vfs_open+0xa0/0xd0 fs/open.c:914
 do_last fs/namei.c:3420 [inline]
 path_openat+0x10df/0x4500 fs/namei.c:3537
 do_filp_open+0x1a1/0x280 fs/namei.c:3567
 do_sys_open+0x3fe/0x5d0 fs/open.c:1097
 __do_sys_open fs/open.c:1115 [inline]
 __se_sys_open fs/open.c:1110 [inline]
 __x64_sys_open+0x7e/0xc0 fs/open.c:1110
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4146a1
Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 0a fa ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007f5d3a16c7a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00000000004146a1
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00007f5d3a16c850
RBP: 000000000075bf20 R08: 000000000000000f R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f5d3a16d6d4
R13: 00000000004caf8f R14: 00000000004e44c8 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..