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 ffff8801d69f9c40 by task syz-executor0/3598

CPU: 1 PID: 3598 Comm: syz-executor0 Not tainted 4.14.0-rc2-next-20170927+ #30
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+0x25b/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+0x137a/0x1d50 arch/x86/kvm/../../../virt/kvm/eventfd.c:572
 kvm_vm_ioctl+0x1079/0x1c40 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2988
 vfs_ioctl fs/ioctl.c:45 [inline]
 do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685
 SYSC_ioctl fs/ioctl.c:700 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
 entry_SYSCALL_64_fastpath+0x1f/0xbe
RIP: 0033:0x4520a9
RSP: 002b:00007f66360c4c08 EFLAGS: 00000216 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000007180b0 RCX: 00000000004520a9
RDX: 0000000020025fe0 RSI: 000000004020ae76 RDI: 000000000000000f
RBP: 0000000000000086 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000216 R12: 00000000004bbcbf
R13: 00000000ffffffff R14: 0000000020571ff7 R15: 0000000000000000

Allocated by task 3598:
 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+0x16c/0x1d50 arch/x86/kvm/../../../virt/kvm/eventfd.c:572
 kvm_vm_ioctl+0x1079/0x1c40 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2988
 vfs_ioctl fs/ioctl.c:45 [inline]
 do_vfs_ioctl+0x1b1/0x1530 fs/ioctl.c:685
 SYSC_ioctl fs/ioctl.c:700 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:691
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Freed by task 2997:
 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+0x3c9/0x4b0 kernel/kthread.c:242
 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:431

The buggy address belongs to the object at ffff8801d69f9ac0
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 384 bytes inside of
 512-byte region [ffff8801d69f9ac0, ffff8801d69f9cc0)
The buggy address belongs to the page:
page:ffffea00075a7e40 count:1 mapcount:0 mapping:ffff8801d69f90c0 index:0x0
flags: 0x200000000000100(slab)
raw: 0200000000000100 ffff8801d69f90c0 0000000000000000 0000000100000006
raw: ffffea00075ea560 ffffea00076b59a0 ffff8801dac00940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d69f9b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d69f9b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d69f9c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8801d69f9c80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801d69f9d00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================