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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WARNING: CPU: 0 PID: 6873 at arch/x86/kvm/vmx/vmx.c:4809 handle_exception_nmi+0x10e1/0x12d0 arch/x86/kvm/vmx/vmx.c:4809
Kernel panic - not syncing: panic_on_warn set ...
CPU: 1 PID: 6873 Comm: syz-executor199 Not tainted 5.9.0-rc7-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+0x198/0x1fd lib/dump_stack.c:118
 panic+0x382/0x7fb kernel/panic.c:231
 __warn.cold+0x20/0x4b kernel/panic.c:600
 report_bug+0x1bd/0x210 lib/bug.c:198
 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234
 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254
 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536
RIP: 0010:handle_exception_nmi+0x10e1/0x12d0 arch/x86/kvm/vmx/vmx.c:4809
Code: 0f 84 16 f3 ff ff e8 3e 5d 5a 00 48 89 ef c7 85 ac 0e 00 00 00 00 00 00 e8 5c 87 f0 ff 41 89 c4 e9 fd f2 ff ff e8 1f 5d 5a 00 <0f> 0b e9 85 f8 ff ff e8 13 5d 5a 00 be f5 ff ff ff bf 01 00 00 00
RSP: 0018:ffffc90005477b58 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff811bd9f5
RDX: ffff8880949ae200 RSI: ffffffff811be171 RDI: 0000000000000001
RBP: ffff888092254040 R08: 0000000000000001 R09: ffff888092254387
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000002
R13: fffffffffffffff8 R14: ffff888092254380 R15: 0000000000000000
 vmx_handle_exit+0x2a6/0x1510 arch/x86/kvm/vmx/vmx.c:6123
 vcpu_enter_guest+0x18f4/0x3c20 arch/x86/kvm/x86.c:8655
 vcpu_run arch/x86/kvm/x86.c:8720 [inline]
 kvm_arch_vcpu_ioctl_run+0x440/0x1780 arch/x86/kvm/x86.c:8937
 kvm_vcpu_ioctl+0x467/0xdf0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3230
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x193/0x200 fs/ioctl.c:739
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x442839
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 9b 0b fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffef04101d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000442839
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00000000006cd018 R08: 0000000000000000 R09: 00000000004002c8
R10: 0000000000000012 R11: 0000000000000246 R12: 0000000000403860
R13: 00000000004038f0 R14: 0000000000000000 R15: 0000000000000000
Kernel Offset: disabled
Rebooting in 86400 seconds..