BUG: KASAN: use-after-free in __list_add include/linux/list.h:64 [inline]
BUG: KASAN: use-after-free in list_add include/linux/list.h:79 [inline]
BUG: KASAN: use-after-free in irq_bypass_register_consumer+0x4b4/0x500 virt/lib/irqbypass.c:217
Write of size 8 at addr ffff8801ce954ba8 by task syz-executor2/3724

CPU: 1 PID: 3724 Comm: syz-executor2 Not tainted 4.14.0-rc8+ #83
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 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:64 [inline]
 list_add include/linux/list.h:79 [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:2991
 kvm_vm_compat_ioctl+0x2ed/0x3e0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3135
 C_SYSC_ioctl fs/compat_ioctl.c:1594 [inline]
 compat_SyS_ioctl+0x1d7/0x3290 fs/compat_ioctl.c:1541
 do_syscall_32_irqs_on arch/x86/entry/common.c:329 [inline]
 do_fast_syscall_32+0x3f2/0xf05 arch/x86/entry/common.c:391
 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125
RIP: 0023:0xf7f69c79
RSP: 002b:00000000f7f4401c EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000010 RCX: 000000004020ae76
RDX: 0000000020227000 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 3724:
 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:3628
 kmalloc include/linux/slab.h:494 [inline]
 kzalloc include/linux/slab.h:667 [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:2991
 kvm_vm_compat_ioctl+0x2ed/0x3e0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3135
 C_SYSC_ioctl fs/compat_ioctl.c:1594 [inline]
 compat_SyS_ioctl+0x1d7/0x3290 fs/compat_ioctl.c:1541
 do_syscall_32_irqs_on arch/x86/entry/common.c:329 [inline]
 do_fast_syscall_32+0x3f2/0xf05 arch/x86/entry/common.c:391
 entry_SYSENTER_compat+0x51/0x60 arch/x86/entry/entry_64_compat.S:125

Freed by task 3246:
 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:3504 [inline]
 kfree+0xca/0x250 mm/slab.c:3821
 irqfd_shutdown+0x13c/0x1a0 arch/x86/kvm/../../../virt/kvm/eventfd.c:148
 process_one_work+0xbf0/0x1bc0 kernel/workqueue.c:2113
 worker_thread+0x223/0x1990 kernel/workqueue.c:2247
 kthread+0x35e/0x430 kernel/kthread.c:231
 ret_from_fork+0x2a/0x40 arch/x86/entry/entry_64.S:432

The buggy address belongs to the object at ffff8801ce954a40
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 360 bytes inside of
 512-byte region [ffff8801ce954a40, ffff8801ce954c40)
The buggy address belongs to the page:
page:ffffea00073a5500 count:1 mapcount:0 mapping:ffff8801ce954040 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801ce954040 0000000000000000 0000000100000006
raw: ffffea00073a70e0 ffffea00074b95e0 ffff8801dac00940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801ce954a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801ce954b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801ce954b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff8801ce954c00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8801ce954c80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================