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.
------------[ cut here ]------------
WARNING: CPU: 1 PID: 4242 at arch/x86/kvm/x86.c:11209 kvm_arch_vcpu_ioctl_run+0x22b1/0x2470
Modules linked in:
CPU: 1 PID: 4242 Comm: syz-executor156 Tainted: G        W          6.1.121-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
RIP: 0010:kvm_arch_vcpu_ioctl_run+0x22b1/0x2470 arch/x86/kvm/x86.c:11209
Code: e8 44 7b d1 00 e9 62 eb ff ff 44 89 f9 80 e1 07 38 c1 0f 8c 6a eb ff ff 4c 89 ff e8 29 7b d1 00 e9 5d eb ff ff e8 5f f0 79 00 <0f> 0b e9 07 fa ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 05 f9 ff
RSP: 0018:ffffc90003c07c68 EFLAGS: 00010293
RAX: ffffffff8110ac11 RBX: 0000000000000000 RCX: ffff88803130bb80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff888030cd02ec R08: ffffffff81180351 R09: fffffbfff2249c66
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88803130bb80
R13: ffff888030cd0000 R14: ffff888024d50000 R15: dffffc0000000000
FS:  0000555572f5e380(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a751fc4d00 CR3: 000000007c8b4000 CR4: 00000000003526e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kvm_vcpu_ioctl+0x7f0/0xcf0 virt/kvm/kvm_main.c:4122
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f6317d1b429
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff4d4caf38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fff4d4cb108 RCX: 00007f6317d1b429
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007f6317d8e610 R08: 00007fff4d4cb108 R09: 00007fff4d4cb108
R10: 00007fff4d4cb108 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fff4d4cb0f8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>