L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.
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BUG: KASAN: slab-out-of-bounds in search_memslots include/linux/kvm_host.h:1051 [inline]
BUG: KASAN: slab-out-of-bounds in __gfn_to_memslot include/linux/kvm_host.h:1063 [inline]
BUG: KASAN: slab-out-of-bounds in kvm_vcpu_gfn_to_memslot+0x50e/0x540 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1603
Read of size 8 at addr ffff8880a80c1468 by task syz-executor412/7057

CPU: 0 PID: 7057 Comm: syz-executor412 Not tainted 5.6.0-syzkaller #0
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+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x315 mm/kasan/report.c:374
 __kasan_report.cold+0x35/0x4d mm/kasan/report.c:503
 kasan_report+0x33/0x50 mm/kasan/common.c:648
 search_memslots include/linux/kvm_host.h:1051 [inline]
 __gfn_to_memslot include/linux/kvm_host.h:1063 [inline]
 kvm_vcpu_gfn_to_memslot+0x50e/0x540 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1603
 try_async_pf+0x12b/0xac0 arch/x86/kvm/mmu/mmu.c:4097
 direct_page_fault+0x27d/0x1d70 arch/x86/kvm/mmu/mmu.c:4146
 kvm_mmu_do_page_fault arch/x86/kvm/mmu.h:115 [inline]
 kvm_mmu_page_fault+0x187/0x15d0 arch/x86/kvm/mmu/mmu.c:5446
 vmx_handle_exit+0x2b8/0x1700 arch/x86/kvm/vmx/vmx.c:5953
 vcpu_enter_guest+0xfea/0x59d0 arch/x86/kvm/x86.c:8470
 vcpu_run arch/x86/kvm/x86.c:8533 [inline]
 kvm_arch_vcpu_ioctl_run+0x3fb/0x16a0 arch/x86/kvm/x86.c:8755
 kvm_vcpu_ioctl+0x493/0xe60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3138
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x4401d9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 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 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffdeabc9e38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401d9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00000000006ca018 R08: 00000000004002c8 R09: 00000000004002c8
R10: 00000000004002c8 R11: 0000000000000246 R12: 0000000000401a60
R13: 0000000000401af0 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 7057:
 save_stack+0x1b/0x80 mm/kasan/common.c:72
 set_track mm/kasan/common.c:80 [inline]
 __kasan_kmalloc mm/kasan/common.c:518 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:491
 kmalloc_node include/linux/slab.h:578 [inline]
 kvmalloc_node+0x61/0xf0 mm/util.c:574
 kvmalloc include/linux/mm.h:733 [inline]
 kvzalloc include/linux/mm.h:741 [inline]
 kvm_dup_memslots arch/x86/kvm/../../../virt/kvm/kvm_main.c:1101 [inline]
 kvm_set_memslot+0x115/0x1530 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1118
 __kvm_set_memory_region+0xcf7/0x1320 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1300
 __x86_set_memory_region+0x2a3/0x5a0 arch/x86/kvm/x86.c:9845
 alloc_apic_access_page arch/x86/kvm/vmx/vmx.c:3544 [inline]
 vmx_create_vcpu+0x2107/0x2b40 arch/x86/kvm/vmx/vmx.c:6772
 kvm_arch_vcpu_create+0x6ef/0xb80 arch/x86/kvm/x86.c:9365
 kvm_vm_ioctl_create_vcpu arch/x86/kvm/../../../virt/kvm/kvm_main.c:3030 [inline]
 kvm_vm_ioctl+0x15f7/0x23e0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3585
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:763
 __do_sys_ioctl fs/ioctl.c:772 [inline]
 __se_sys_ioctl fs/ioctl.c:770 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:770
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff8880a80c1000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1128 bytes inside of
 2048-byte region [ffff8880a80c1000, ffff8880a80c1800)
The buggy address belongs to the page:
page:ffffea0002a03040 refcount:1 mapcount:0 mapping:00000000fc63864e index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000227fec8 ffffea00027dde48 ffff8880aa000e00
raw: 0000000000000000 ffff8880a80c1000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a80c1300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8880a80c1380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff8880a80c1400: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
                                                          ^
 ffff8880a80c1480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8880a80c1500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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