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: 3979 at arch/x86/kvm/x86.c:11167 kvm_arch_vcpu_ioctl_run+0x1f38/0x20c0
Modules linked in:
CPU: 0 PID: 3979 Comm: syz-executor.0 Not tainted 6.1.29-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023
RIP: 0010:kvm_arch_vcpu_ioctl_run+0x1f38/0x20c0 arch/x86/kvm/x86.c:11167
Code: df e8 8c 4f cf 00 e9 1c ed ff ff 89 e9 80 e1 07 38 c1 0f 8c 26 ed ff ff 48 89 ef e8 72 4f cf 00 e9 19 ed ff ff e8 88 21 79 00 <0f> 0b e9 3f fa ff ff 89 d9 80 e1 07 80 c1 03 38 c1 0f 8c 4e f9 ff
RSP: 0018:ffffc9000603fc70 EFLAGS: 00010293
RAX: ffffffff81107b38 RBX: 0000000000000000 RCX: ffff88801c01bb80
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff8117d211 R09: fffffbfff204e655
R10: 0000000000000000 R11: dffffc0000000001 R12: ffff88801d7b8000
R13: dffffc0000000000 R14: ffff8880285e0000 R15: ffff8880285e00e8
FS:  00007f158a7e9700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000563dc2d4f008 CR3: 000000001e722000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kvm_vcpu_ioctl+0x7f0/0xcf0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:4087
 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:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f1589a8c0f9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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:00007f158a7e9168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1589babf80 RCX: 00007f1589a8c0f9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007f1589ae7b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffc43aa00ff R14: 00007f158a7e9300 R15: 0000000000022000
 </TASK>