ALSA: seq fatal error: cannot create timer (-22)
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BUG: KASAN: use-after-free in kvm_iodevice_destructor include/kvm/iodev.h:72 [inline]
BUG: KASAN: use-after-free in kvm_io_bus_destroy arch/x86/kvm/../../../virt/kvm/kvm_main.c:3397 [inline]
BUG: KASAN: use-after-free in kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:736 [inline]
BUG: KASAN: use-after-free in kvm_put_kvm+0xd7c/0xff0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:766
Read of size 8 at addr ffff8881b947eb10 by task syz-executor4/12675

CPU: 1 PID: 12675 Comm: syz-executor4 Not tainted 4.20.0-rc5-next-20181207+ #163
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
 print_address_description.cold.4+0x9/0x1ff mm/kasan/report.c:187
 kasan_report.cold.5+0x1b/0x39 mm/kasan/report.c:317
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
 kvm_iodevice_destructor include/kvm/iodev.h:72 [inline]
 kvm_io_bus_destroy arch/x86/kvm/../../../virt/kvm/kvm_main.c:3397 [inline]
 kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:736 [inline]
 kvm_put_kvm+0xd7c/0xff0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:766
 kvm_vm_release+0x42/0x50 arch/x86/kvm/../../../virt/kvm/kvm_main.c:777
 __fput+0x3bc/0xa90 fs/file_table.c:279
 ____fput+0x15/0x20 fs/file_table.c:312
 task_work_run+0x1e8/0x2a0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x318/0x380 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x6be/0x820 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x411111
Code: 75 14 b8 03 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 34 19 00 00 c3 48 83 ec 08 e8 0a fc ff ff 48 89 04 24 b8 03 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 53 fc ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007ffde9d686c0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000006 RCX: 0000000000411111
RDX: 0000000000000000 RSI: 0000000000730b90 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 00007ffde9d685f0 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 0000000000000325 R15: 0000000000000004

Allocated by task 12676:
 save_stack+0x43/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 kasan_kmalloc+0xcb/0xd0 mm/kasan/common.c:482
 kmem_cache_alloc_trace+0x154/0x740 mm/slab.c:3607
 kmalloc include/linux/slab.h:545 [inline]
 kzalloc include/linux/slab.h:740 [inline]
 kvm_vm_ioctl_register_coalesced_mmio+0xe8/0x4f0 arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:147
 kvm_vm_ioctl+0x594/0x1d60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3010
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 12681:
 save_stack+0x43/0xd0 mm/kasan/common.c:73
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:444
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:452
 __cache_free mm/slab.c:3485 [inline]
 kfree+0xcf/0x230 mm/slab.c:3804
 coalesced_mmio_destructor+0x1ad/0x2a0 arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:99
 kvm_iodevice_destructor include/kvm/iodev.h:73 [inline]
 kvm_vm_ioctl_unregister_coalesced_mmio+0x263/0x330 arch/x86/kvm/../../../virt/kvm/coalesced_mmio.c:184
 kvm_vm_ioctl+0x6bc/0x1d60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3019
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881b947eb00
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 16 bytes inside of
 64-byte region [ffff8881b947eb00, ffff8881b947eb40)
The buggy address belongs to the page:
page:ffffea0006e51f80 count:1 mapcount:0 mapping:ffff8881da800340 index:0xffff8881b947ec00
flags: 0x2fffc0000000200(slab)
raw: 02fffc0000000200 ffffea0006f39808 ffffea0007368448 ffff8881da800340
raw: ffff8881b947ec00 ffff8881b947e000 000000010000001b 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881b947ea00: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
 ffff8881b947ea80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8881b947eb00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
                         ^
 ffff8881b947eb80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff8881b947ec00: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
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