sock: process `syz-executor5' is using obsolete getsockopt SO_BSDCOMPAT
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BUG: KASAN: use-after-free in irq_bypass_register_consumer+0x4f0/0x500 virt/lib/irqbypass.c:198
Read of size 8 at addr ffff8801d63f4478 by task syz-executor2/23041

CPU: 1 PID: 23041 Comm: syz-executor2 Not tainted 4.15.0-rc8-next-20180116+ #98
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:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report+0x23b/0x360 mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 irq_bypass_register_consumer+0x4f0/0x500 virt/lib/irqbypass.c:198
 kvm_irqfd_assign arch/x86/kvm/../../../virt/kvm/eventfd.c:417 [inline]
 kvm_irqfd+0x1396/0x1d70 arch/x86/kvm/../../../virt/kvm/eventfd.c:572
 kvm_vm_ioctl+0x109b/0x1c60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2992
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x452df9
RSP: 002b:00007f96ea657c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452df9
RDX: 0000000020670fe0 RSI: 000000004020ae76 RDI: 000000000000001b
RBP: 0000000000000622 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f73d0
R13: 00000000ffffffff R14: 00007f96ea6586d4 R15: 0000000000000000

Allocated by task 23041:
 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:552
 kmem_cache_alloc_trace+0x136/0x750 mm/slab.c:3607
 kmalloc include/linux/slab.h:512 [inline]
 kzalloc include/linux/slab.h:701 [inline]
 kvm_irqfd_assign arch/x86/kvm/../../../virt/kvm/eventfd.c:296 [inline]
 kvm_irqfd+0x16c/0x1d70 arch/x86/kvm/../../../virt/kvm/eventfd.c:572
 kvm_vm_ioctl+0x109b/0x1c60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2992
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 entry_SYSCALL_64_fastpath+0x29/0xa0

Freed by task 4224:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
 __cache_free mm/slab.c:3485 [inline]
 kfree+0xd9/0x260 mm/slab.c:3800
 irqfd_shutdown+0x13c/0x1a0 arch/x86/kvm/../../../virt/kvm/eventfd.c:148
 process_one_work+0xbbf/0x1af0 kernel/workqueue.c:2113
 worker_thread+0x223/0x1990 kernel/workqueue.c:2247
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x37/0x50 arch/x86/entry/entry_64.S:530

The buggy address belongs to the object at ffff8801d63f4300
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 376 bytes inside of
 512-byte region [ffff8801d63f4300, ffff8801d63f4500)
The buggy address belongs to the page:
page:ffffea000758fd00 count:1 mapcount:0 mapping:ffff8801d63f4080 index:0xffff8801d63f4a80
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d63f4080 ffff8801d63f4a80 0000000100000005
raw: ffffea000763f460 ffffea000758fde0 ffff8801dac00940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d63f4300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d63f4380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d63f4400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8801d63f4480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d63f4500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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