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_map_gfn+0x933/0xa10 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2060
Read of size 8 at addr ffff88808e20b468 by task syz-executor368/7090

CPU: 0 PID: 7090 Comm: syz-executor368 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_map_gfn+0x933/0xa10 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2060
 kvm_steal_time_set_preempted arch/x86/kvm/x86.c:3609 [inline]
 kvm_arch_vcpu_put+0x3b9/0x530 arch/x86/kvm/x86.c:3642
 vcpu_put+0x1b/0x70 arch/x86/kvm/../../../virt/kvm/kvm_main.c:220
 kvm_arch_vcpu_ioctl+0x1ae/0x2c20 arch/x86/kvm/x86.c:4620
 kvm_vcpu_ioctl+0x866/0xe60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3291
 kvm_vcpu_compat_ioctl+0x1ab/0x350 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3334
 __do_compat_sys_ioctl fs/ioctl.c:857 [inline]
 __se_compat_sys_ioctl fs/ioctl.c:808 [inline]
 __ia32_compat_sys_ioctl+0x23d/0x2b0 fs/ioctl.c:808
 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
 do_fast_syscall_32+0x270/0xe90 arch/x86/entry/common.c:396
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Allocated by task 7090:
 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
 kvm_vm_compat_ioctl+0x125/0x240 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3798
 __do_compat_sys_ioctl fs/ioctl.c:857 [inline]
 __se_compat_sys_ioctl fs/ioctl.c:808 [inline]
 __ia32_compat_sys_ioctl+0x23d/0x2b0 fs/ioctl.c:808
 do_syscall_32_irqs_on arch/x86/entry/common.c:337 [inline]
 do_fast_syscall_32+0x270/0xe90 arch/x86/entry/common.c:396
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139

Freed by task 0:
(stack is not available)

The buggy address belongs to the object at ffff88808e20b000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 1128 bytes inside of
 2048-byte region [ffff88808e20b000, ffff88808e20b800)
The buggy address belongs to the page:
page:ffffea00023882c0 refcount:1 mapcount:0 mapping:00000000044fe846 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00027cbcc8 ffffea0002591e08 ffff8880aa000e00
raw: 0000000000000000 ffff88808e20b000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88808e20b300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88808e20b380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88808e20b400: 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc fc
                                                          ^
 ffff88808e20b480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88808e20b500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
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