BUG: KASAN: use-after-free in arch_local_irq_enable arch/x86/include/asm/paravirt.h:787 [inline]
BUG: KASAN: use-after-free in __do_page_fault+0xc03/0xd60 arch/x86/mm/fault.c:1357
Read of size 8 at addr ffff8801cf2ef890 by task syz-executor4/3914

CPU: 0 PID: 3914 Comm: syz-executor4 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_load8_noabort+0x14/0x20 mm/kasan/report.c:430
 arch_local_irq_enable arch/x86/include/asm/paravirt.h:787 [inline]
 __do_page_fault+0xc03/0xd60 arch/x86/mm/fault.c:1357
 do_page_fault+0xee/0x720 arch/x86/mm/fault.c:1520
 page_fault+0x22/0x30 arch/x86/entry/entry_64.S:1066
RIP: 0033:0x44bcf0
RSP: 002b:00007f5e73838758 EFLAGS: 00010202
RAX: 00007f5e73838800 RBX: 0000000000718000 RCX: 000000000000000e
RDX: 0000000000000400 RSI: 0000000020012fe0 RDI: 00007f5e73838800
RBP: 0000000000005e10 R08: 0000000000000400 R09: 0000000000000000
R10: 00000000000f4245 R11: 0000000000000246 R12: 00000000004bbc27
R13: 00000000ffffffff R14: 0000000020012fee R15: 0000000000000000

Allocated by task 3914:
 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
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3561
 kmem_cache_zalloc include/linux/slab.h:656 [inline]
 mmap_region+0x7ee/0x15a0 mm/mmap.c:1658
 do_mmap+0x6a1/0xd50 mm/mmap.c:1468
 do_mmap_pgoff include/linux/mm.h:2150 [inline]
 vm_mmap_pgoff+0x1de/0x280 mm/util.c:333
 SYSC_mmap_pgoff mm/mmap.c:1518 [inline]
 SyS_mmap_pgoff+0x23b/0x5f0 mm/mmap.c:1476
 SYSC_mmap arch/x86/kernel/sys_x86_64.c:99 [inline]
 SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:90
 entry_SYSCALL_64_fastpath+0x1f/0xbe

Freed by task 3925:
 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]
 kmem_cache_free+0x77/0x280 mm/slab.c:3763
 remove_vma+0x162/0x1b0 mm/mmap.c:176
 remove_vma_list mm/mmap.c:2475 [inline]
 do_munmap+0x82a/0xdf0 mm/mmap.c:2714
 mmap_region+0x59e/0x15a0 mm/mmap.c:1631
 do_mmap+0x6a1/0xd50 mm/mmap.c:1468
 do_mmap_pgoff include/linux/mm.h:2150 [inline]
 vm_mmap_pgoff+0x1de/0x280 mm/util.c:333
 SYSC_mmap_pgoff mm/mmap.c:1518 [inline]
 SyS_mmap_pgoff+0x23b/0x5f0 mm/mmap.c:1476
 SYSC_mmap arch/x86/kernel/sys_x86_64.c:99 [inline]
 SyS_mmap+0x16/0x20 arch/x86/kernel/sys_x86_64.c:90
 entry_SYSCALL_64_fastpath+0x1f/0xbe

The buggy address belongs to the object at ffff8801cf2ef840
 which belongs to the cache vm_area_struct of size 200
The buggy address is located 80 bytes inside of
 200-byte region [ffff8801cf2ef840, ffff8801cf2ef908)
The buggy address belongs to the page:
page:ffffea00073cbbc0 count:1 mapcount:0 mapping:ffff8801cf2ef000 index:0x0
flags: 0x200000000000100(slab)
raw: 0200000000000100 ffff8801cf2ef000 0000000000000000 000000010000000f
raw: ffffea000733a320 ffffea00072f5420 ffff8801dae0a9c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801cf2ef780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801cf2ef800: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
>ffff8801cf2ef880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                         ^
 ffff8801cf2ef900: fb fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb
 ffff8801cf2ef980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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