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: 4244 at arch/x86/kvm/x86.c:11209 kvm_arch_vcpu_ioctl_run+0x22b1/0x2470 arch/x86/kvm/x86.c:-1
Modules linked in:
CPU: 0 PID: 4244 Comm: syz-executor172 Not tainted 6.1.132-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
RIP: 0010:kvm_arch_vcpu_ioctl_run+0x22b1/0x2470 arch/x86/kvm/x86.c:11209
Code: e8 54 5a 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 39 5a d1 00 e9 5d eb ff ff e8 cf f8 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:ffffc90003d67c68 EFLAGS: 00010293
RAX: ffffffff8110b181 RBX: 0000000000000000 RCX: ffff88807d7b3b80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffff8880769682ec R08: ffffffff81180801 R09: fffffbfff2257666
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88807d7b3b80
R13: ffff888076968000 R14: ffff888027ea3000 R15: dffffc0000000000
FS:  0000555592ccb380(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055a748409e70 CR3: 0000000028ff8000 CR4: 00000000003526f0
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: 0033:0x7f878476b369
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:00007ffdd01f9dd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffdd01f9fa8 RCX: 00007f878476b369
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007f87847de610 R08: 00007ffdd01f9fa8 R09: 00007ffdd01f9fa8
R10: 00007ffdd01f9fa8 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffdd01f9f98 R14: 0000000000000001 R15: 0000000000000001
 </TASK>