syzbot

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: 4504 at arch/x86/kvm/x86.c:10351 kvm_arch_vcpu_ioctl_run+0x1bc4/0x1f40 arch/x86/kvm/x86.c:10351
Modules linked in:
CPU: 0 PID: 4504 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:kvm_arch_vcpu_ioctl_run+0x1bc4/0x1f40 arch/x86/kvm/x86.c:10351
Code: e8 01 41 ad 00 e9 03 e9 ff ff 44 89 f9 80 e1 07 38 c1 0f 8c d5 ed ff ff 4c 89 ff e8 e6 40 ad 00 e9 c8 ed ff ff e8 dc da 68 00 <0f> 0b e9 31 fd ff ff 44 89 f9 80 e1 07 38 c1 0f 8c d2 ed ff ff 4c
RSP: 0018:ffffc900032ffc30 EFLAGS: 00010293
RAX: ffffffff810eefd4 RBX: ffff88807b254000 RCX: ffff88801d093b80
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff88807b254000
RBP: 0000000000000000 R08: dffffc0000000000 R09: fffffbfff1ad3196
R10: fffffbfff1ad3196 R11: 1ffffffff1ad3195 R12: ffff88806f9a6001
R13: 1ffff1100f64a81e R14: ffff88807b2540f0 R15: ffff88806f9a6000
FS:  00005555951ff500(0000) GS:ffff8880b9000000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005649a7ef7950 CR3: 000000007d72f000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 kvm_vcpu_ioctl+0x887/0xb80 virt/kvm/kvm_main.c:3894
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fd10d526be9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff4623cb48 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fd10d75dfa0 RCX: 00007fd10d526be9
RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005
RBP: 00007fd10d5a9e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd10d75dfa0 R14: 00007fd10d75dfa0 R15: 0000000000000003
 </TASK>