BUG: KASAN: use-after-free in __list_add include/linux/list.h:63 [inline]
BUG: KASAN: use-after-free in list_add include/linux/list.h:78 [inline]
BUG: KASAN: use-after-free in irq_bypass_register_consumer+0x4b4/0x500 virt/lib/irqbypass.c:217
Write of size 8 at addr ffff8801cbe69c40 by task syz-executor0/4638

CPU: 1 PID: 4638 Comm: syz-executor0 Not tainted 4.14.0-rc1+ #1
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:16 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:52
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x24e/0x340 mm/kasan/report.c:409
 __asan_report_store8_noabort+0x17/0x20 mm/kasan/report.c:435
 __list_add include/linux/list.h:63 [inline]
 list_add include/linux/list.h:78 [inline]
 irq_bypass_register_consumer+0x4b4/0x500 virt/lib/irqbypass.c:217
 kvm_irqfd_assign arch/x86/kvm/../../../virt/kvm/eventfd.c:417 [inline]
 kvm_irqfd+0x13c9/0x1db0 arch/x86/kvm/../../../virt/kvm/eventfd.c:574
 kvm_vm_ioctl+0x1079/0x1c40 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2991
 kvm_vm_compat_ioctl+0x2ed/0x3e0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3135
 C_SYSC_ioctl fs/compat_ioctl.c:1593 [inline]
 compat_SyS_ioctl+0x1da/0x3300 fs/compat_ioctl.c:1540
 do_syscall_32_irqs_on arch/x86/entry/common.c:329 [inline]
 do_fast_syscall_32+0x3f2/0xeed arch/x86/entry/common.c:391
 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:124
RIP: 0023:0xf7f9ec79
RSP: 002b:00000000f7f7905c EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000004020ae76
RDX: 000000002000d000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 4638:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3627
 kmalloc include/linux/slab.h:493 [inline]
 kzalloc include/linux/slab.h:666 [inline]
 kvm_irqfd_assign arch/x86/kvm/../../../virt/kvm/eventfd.c:296 [inline]
 kvm_irqfd+0x1b6/0x1db0 arch/x86/kvm/../../../virt/kvm/eventfd.c:574
 kvm_vm_ioctl+0x1079/0x1c40 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2991
 kvm_vm_compat_ioctl+0x2ed/0x3e0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3135
 C_SYSC_ioctl fs/compat_ioctl.c:1593 [inline]
 compat_SyS_ioctl+0x1da/0x3300 fs/compat_ioctl.c:1540
 do_syscall_32_irqs_on arch/x86/entry/common.c:329 [inline]
 do_fast_syscall_32+0x3f2/0xeed arch/x86/entry/common.c:391
 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:124

Freed by task 24:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:59
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3503 [inline]
 kfree+0xca/0x250 mm/slab.c:3820
 irqfd_shutdown+0x13c/0x1a0 arch/x86/kvm/../../../virt/kvm/eventfd.c:148
 process_one_work+0xbfa/0x1bd0 kernel/workqueue.c:2119
 worker_thread+0x223/0x1860 kernel/workqueue.c:2253
 kthread+0x39c/0x470 kernel/kthread.c:231
 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431

The buggy address belongs to the object at ffff8801cbe69ac0
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 384 bytes inside of
 512-byte region [ffff8801cbe69ac0, ffff8801cbe69cc0)
The buggy address belongs to the page:
page:ffffea00072f9a40 count:1 mapcount:0 mapping:ffff8801cbe690c0 index:0x0
flags: 0x200000000000100(slab)
raw: 0200000000000100 ffff8801cbe690c0 0000000000000000 0000000100000006
raw: ffffea00072f9e60 ffffea00072e72a0 ffff8801dac00940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cbe69b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801cbe69b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801cbe69c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8801cbe69c80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801cbe69d00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================