kmem_cache_zalloc include/linux/slab.h:697 [inline]
 mmu_topup_memory_cache arch/x86/kvm/mmu.c:865 [inline]
 mmu_topup_memory_caches+0xf7/0x3a0 arch/x86/kvm/mmu.c:911
 kvm_mmu_load+0x21/0x10e0 arch/x86/kvm/mmu.c:4656
 kvm_mmu_reload arch/x86/kvm/mmu.h:85 [inline]
 vcpu_enter_guest+0x3aa6/0x6090 arch/x86/kvm/x86.c:7388
==================================================================
BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:188 [inline]
BUG: KASAN: use-after-free in list_empty include/linux/list.h:203 [inline]
BUG: KASAN: use-after-free in shrink_slab_memcg mm/vmscan.c:595 [inline]
BUG: KASAN: use-after-free in shrink_slab+0xa04/0xa60 mm/vmscan.c:671
Read of size 8 at addr ffff8801b60e8e98 by task syz-executor1/13491

 vcpu_run arch/x86/kvm/x86.c:7585 [inline]
 kvm_arch_vcpu_ioctl_run+0x33e/0x1690 arch/x86/kvm/x86.c:7762
 kvm_vcpu_ioctl+0x7b8/0x1300 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2580
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702
 __do_sys_ioctl fs/ioctl.c:709 [inline]
 __se_sys_ioctl fs/ioctl.c:707 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455ab9
Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007f177b7eec68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f177b7ef6d4 RCX: 0000000000455ab9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000015
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000016
R13: 00000000004bdc94 R14: 00000000004cc6d0 R15: 0000000000000009
CPU: 0 PID: 13491 Comm: syz-executor1 Not tainted 4.18.0-rc4-next-20180713+ #7
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+0x1c9/0x2b4 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x30d mm/kasan/report.c:412
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/report.c:433
 __read_once_size include/linux/compiler.h:188 [inline]
 list_empty include/linux/list.h:203 [inline]
 shrink_slab_memcg mm/vmscan.c:595 [inline]
 shrink_slab+0xa04/0xa60 mm/vmscan.c:671
 shrink_node+0x429/0x16a0 mm/vmscan.c:2735
 shrink_zones mm/vmscan.c:2964 [inline]
 do_try_to_free_pages+0x3e7/0x1290 mm/vmscan.c:3026
 try_to_free_mem_cgroup_pages+0x49d/0xc90 mm/vmscan.c:3324
 memory_high_write+0x283/0x310 mm/memcontrol.c:5611
 cgroup_file_write+0x31f/0x840 kernel/cgroup/cgroup.c:3502
 kernfs_fop_write+0x2ba/0x480 fs/kernfs/file.c:316
 __vfs_write+0x117/0x9d0 fs/read_write.c:485
 vfs_write+0x1fc/0x560 fs/read_write.c:549
 ksys_write+0x101/0x260 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x455ab9
Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007ff166e36c68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ff166e376d4 RCX: 0000000000455ab9
RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000018
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c2c77 R14: 00000000004d4c80 R15: 0000000000000000

Allocated by task 6656:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554
 getname_flags+0xd0/0x5a0 fs/namei.c:140
 user_path_at_empty+0x2d/0x50 fs/namei.c:2625
 do_readlinkat+0x14b/0x400 fs/stat.c:394
 __do_sys_readlink fs/stat.c:427 [inline]
 __se_sys_readlink fs/stat.c:424 [inline]
 __x64_sys_readlink+0x78/0xb0 fs/stat.c:424
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6656:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x86/0x2d0 mm/slab.c:3756
 putname+0xf2/0x130 fs/namei.c:261
 filename_lookup+0x397/0x510 fs/namei.c:2371
 user_path_at_empty+0x40/0x50 fs/namei.c:2625
 do_readlinkat+0x14b/0x400 fs/stat.c:394
 __do_sys_readlink fs/stat.c:427 [inline]
 __se_sys_readlink fs/stat.c:424 [inline]
 __x64_sys_readlink+0x78/0xb0 fs/stat.c:424
 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 ffff8801b60e8ac0
 which belongs to the cache names_cache of size 4096
The buggy address is located 984 bytes inside of
 4096-byte region [ffff8801b60e8ac0, ffff8801b60e9ac0)
The buggy address belongs to the page:
page:ffffea0006d83a00 count:1 mapcount:0 mapping:ffff8801da987dc0 index:0x0 compound_mapcount: 0
flags: 0x2fffc0000008100(slab|head)
raw: 02fffc0000008100 ffffea00066b8588 ffffea0006d83a88 ffff8801da987dc0
raw: 0000000000000000 ffff8801b60e8ac0 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b60e8d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801b60e8e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801b60e8e80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8801b60e8f00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801b60e8f80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================