------------[ cut here ]------------ refcount_t: increment on 0; use-after-free. WARNING: CPU: 0 PID: 24962 at lib/refcount.c:153 refcount_inc_checked+0x5d/0x70 lib/refcount.c:153 kobject: 'kvm' (0000000044e04acb): kobject_uevent_env Kernel panic - not syncing: panic_on_warn set ... CPU: 0 PID: 24962 Comm: syz-executor2 Not tainted 4.20.0-rc1+ #234 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+0x244/0x39d lib/dump_stack.c:113 kobject: 'kvm' (0000000044e04acb): fill_kobj_path: path = '/devices/virtual/misc/kvm' panic+0x2ad/0x55c kernel/panic.c:188 kobject: 'loop5' (00000000a118152a): kobject_uevent_env __warn.cold.8+0x20/0x45 kernel/panic.c:540 kobject: 'loop5' (00000000a118152a): fill_kobj_path: path = '/devices/virtual/block/loop5' report_bug+0x254/0x2d0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290 kobject: 'kvm' (0000000044e04acb): kobject_uevent_env invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969 RIP: 0010:refcount_inc_checked+0x5d/0x70 lib/refcount.c:153 kobject: 'kvm' (0000000044e04acb): fill_kobj_path: path = '/devices/virtual/misc/kvm' Code: 1d 28 fa 7e 06 31 ff 89 de e8 af 1a ed fd 84 db 75 df e8 d6 19 ed fd 48 c7 c7 60 af 60 88 c6 05 08 fa 7e 06 01 e8 33 7b b6 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:ffff8801b67ff780 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffffffff8165e9b5 RDI: 0000000000000005 RBP: ffff8801b67ff788 R08: ffff8801bb0ce340 R09: ffffed003b5c5020 R10: ffffed003b5c5020 R11: ffff8801dae28107 R12: 0000000020000180 R13: ffff8801b67ff838 R14: ffffffff894b6e20 R15: ffff8801bedbd700 kvm_get_kvm arch/x86/kvm/../../../virt/kvm/kvm_main.c:763 [inline] kvm_ioctl_create_device arch/x86/kvm/../../../virt/kvm/kvm_main.c:2930 [inline] kvm_vm_ioctl+0xedf/0x1d60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3122 kvm_vm_compat_ioctl+0x143/0x430 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3178 __do_compat_sys_ioctl fs/compat_ioctl.c:1052 [inline] __se_compat_sys_ioctl fs/compat_ioctl.c:998 [inline] __ia32_compat_sys_ioctl+0x20e/0x630 fs/compat_ioctl.c:998 do_syscall_32_irqs_on arch/x86/entry/common.c:326 [inline] do_fast_syscall_32+0x34d/0xfb2 arch/x86/entry/common.c:397 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f16a29 Code: 85 d2 74 02 89 0a 5b 5d c3 8b 04 24 c3 8b 14 24 c3 8b 3c 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:00000000f7f120cc EFLAGS: 00000296 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000007 RCX: 00000000c00caee0 RDX: 0000000020000180 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..