------------[ cut here ]------------
refcount_t: addition on 0; use-after-free.
WARNING: CPU: 1 PID: 18710 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: 18710 Comm: syz-executor.0 Not tainted 5.5.0-rc3-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014
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 cc 89 e5 fd 84 db 0f 85 33 ff ff ff e8 7f 88 e5 fd 48 c7 c7 80 ca 6f 88 c6 05 a7 6a e5 06 01 e8 db 2f b6 fd <0f> 0b e9 14 ff ff ff e8 60 88 e5 fd 0f b6 1d 8c 6a e5 06 31 ff 89
RSP: 0018:ffffc90001fd7898 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
RDX: 000000000000990b RSI: ffffffff815e8b56 RDI: fffff520003faf05
RBP: ffffc90001fd78a8 R08: ffff88802a344700 R09: ffffed1005a245c9
R10: ffffed1005a245c8 R11: ffff88802d122e43 R12: 0000000000000002
R13: ffff88802a647660 R14: ffff88801dbb3ac0 R15: ffff88801cd79498
 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_compat_sys_open fs/open.c:1134 [inline]
 __se_compat_sys_open fs/open.c:1132 [inline]
 __ia32_compat_sys_open+0x79/0xb0 fs/open.c:1132
 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
 do_fast_syscall_32+0x27b/0xe16 arch/x86/entry/common.c:408
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f56a39
Code: 00 00 00 89 d3 5b 5e 5f 5d c3 b8 80 96 98 00 eb c4 8b 04 24 c3 8b 1c 24 c3 8b 34 24 c3 8b 3c 24 c3 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90
RSP: 002b:00000000f5d30c04 EFLAGS: 00000293 ORIG_RAX: 0000000000000005
RAX: ffffffffffffffda RBX: 00000000f5d30cc0 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000066666667 RDI: 00000000f5d30cc0
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..