------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 0 PID: 17509 at lib/refcount.c:156 refcount_inc_checked lib/refcount.c:156 [inline]
WARNING: CPU: 0 PID: 17509 at lib/refcount.c:156 refcount_inc_checked+0x59/0x60 lib/refcount.c:154
Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 17509 Comm: syz-executor.4 Not tainted 5.4.0-rc6+ #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+0xca/0x13e lib/dump_stack.c:113
 panic+0x2aa/0x6e1 kernel/panic.c:221
 __warn.cold+0x2f/0x33 kernel/panic.c:582
 report_bug+0x27b/0x2f0 lib/bug.c:195
 fixup_bug arch/x86/kernel/traps.c:179 [inline]
 fixup_bug arch/x86/kernel/traps.c:174 [inline]
 do_error_trap+0x12b/0x1e0 arch/x86/kernel/traps.c:272
 do_invalid_op+0x32/0x40 arch/x86/kernel/traps.c:291
 invalid_op+0x23/0x30 arch/x86/entry/entry_64.S:1028
RIP: 0010:refcount_inc_checked lib/refcount.c:156 [inline]
RIP: 0010:refcount_inc_checked+0x59/0x60 lib/refcount.c:154
Code: 1d 94 cb a3 05 31 ff 89 de e8 63 3d 5d ff 84 db 75 e0 e8 2a 3c 5d ff 48 c7 c7 00 80 da 85 c6 05 74 cb a3 05 01 e8 4c d7 32 ff <0f> 0b eb c4 90 90 90 41 57 41 56 41 55 49 89 fd 41 54 55 48 89 f5
RSP: 0018:ffff8881ae32f958 EFLAGS: 00010282
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000006b4a RSI: ffffffff8128c9cd RDI: ffffed1035c65f1d
RBP: ffff8881cd2f1638 R08: ffff8881cd378000 R09: fffffbfff11aadb0
R10: fffffbfff11aadaf R11: ffffffff88d56d7f R12: ffff8881cd2f1600
R13: 0000000000000000 R14: ffff8881c5c709a0 R15: ffff8881ce3091fc
 kref_get include/linux/kref.h:45 [inline]
 kobject_get+0x62/0xc0 lib/kobject.c:644
 cdev_get+0x5c/0xb0 fs/char_dev.c:355
 chrdev_open+0xaa/0x5c0 fs/char_dev.c:400
 do_dentry_open+0x494/0x1120 fs/open.c:797
 do_last fs/namei.c:3408 [inline]
 path_openat+0x1430/0x3ff0 fs/namei.c:3525
 do_filp_open+0x1a1/0x280 fs/namei.c:3555
 do_sys_open+0x3c0/0x580 fs/open.c:1097
 do_syscall_64+0xb7/0x580 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x414401
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:00007f2bcd73c7a0 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 0000000000414401
RDX: 0000000000000000 RSI: 00000000000216bd RDI: 00007f2bcd73c850
RBP: 000000000075bf20 R08: 00007f2bcd73c7b0 R09: 000000000075bf20
R10: 0000000000000000 R11: 0000000000000293 R12: 00007f2bcd73d6d4
R13: 00000000004ca1aa R14: 00000000004e1f38 R15: 00000000ffffffff
Kernel Offset: disabled
Rebooting in 86400 seconds..