------------[ cut here ]------------
refcount_t: increment on 0; use-after-free.
WARNING: CPU: 0 PID: 8586 at lib/refcount.c:153 refcount_inc_checked+0x5d/0x70 lib/refcount.c:153
Kernel panic - not syncing: panic_on_warn set ...

kobject: '7:0' (000000008b475430): kobject_uevent_env
CPU: 0 PID: 8586 Comm: syz-executor4 Not tainted 4.19.0-rc5+ #164
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+0x1c4/0x2b4 lib/dump_stack.c:113
 panic+0x238/0x4e7 kernel/panic.c:184
kobject: '7:0' (000000008b475430): fill_kobj_path: path = '/devices/virtual/bdi/7:0'
 __warn.cold.8+0x163/0x1ba kernel/panic.c:536
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296
kobject: '7:0' (000000008b475430): kobject_cleanup, parent           (null)
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:993
RIP: 0010:refcount_inc_checked+0x5d/0x70 lib/refcount.c:153
Code: 1d ea 9e 62 06 31 ff 89 de e8 6f bc f2 fd 84 db 75 df e8 96 bb f2 fd 48 c7 c7 00 74 40 88 c6 05 ca 9e 62 06 01 e8 83 ae bc fd <0f> 0b eb c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 55 48 89
RSP: 0018:ffff88018cd57780 EFLAGS: 00010286
kobject: '7:0' (000000008b475430): calling ktype release
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffc9000a0ab000
RDX: 0000000000012722 RSI: ffffffff8164e3f5 RDI: 0000000000000005
RBP: ffff88018cd57788 R08: ffff8801d53cc580 R09: ffffed003b5c4fe8
R10: ffffed003b5c4fe8 R11: ffff8801dae27f47 R12: ffff88018cd57838
R13: ffff8801bcfa5880 R14: ffffffff892b6e60 R15: ffffc9000fc8e000
 kvm_get_kvm arch/x86/kvm/../../../virt/kvm/kvm_main.c:766 [inline]
 kvm_ioctl_create_device arch/x86/kvm/../../../virt/kvm/kvm_main.c:2924 [inline]
 kvm_vm_ioctl+0xed7/0x1d40 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3114
kobject: '7:0': free name
kobject: 'mq' (00000000191041b0): kobject_uevent_env
kobject: 'mq' (00000000191041b0): kobject_uevent_env: filter function caused the event to drop!
 kvm_vm_compat_ioctl+0x143/0x430 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3170
kobject: 'queue' (000000002d97c09d): kobject_uevent_env
 __do_compat_sys_ioctl fs/compat_ioctl.c:1419 [inline]
 __se_compat_sys_ioctl fs/compat_ioctl.c:1365 [inline]
 __ia32_compat_sys_ioctl+0x20e/0x630 fs/compat_ioctl.c:1365
 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline]
 do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397
kobject: 'queue' (000000002d97c09d): kobject_uevent_env: filter function caused the event to drop!
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7fdfca9
Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 0c 24 c3 8b 1c 24 c3 90 90 90 90 90 90 90 90 90 90 90 90 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:00000000f5fba0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 000000000000000e RCX: 00000000c00caee0
RDX: 0000000020000340 RSI: 0000000000000000 RDI: 0000000000000000
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..