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.
=============================
WARNING: suspicious RCU usage
5.15.170-syzkaller #0 Not tainted
-----------------------------
include/linux/kvm_host.h:880 suspicious rcu_dereference_check() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
1 lock held by syz-executor250/4161:
 #0: ffff88806fcb40c8 (&vcpu->mutex){+.+.}-{3:3}, at: kvm_vcpu_ioctl+0x1d4/0xcf0 virt/kvm/kvm_main.c:3871

stack backtrace:
CPU: 0 PID: 4161 Comm: syz-executor250 Not tainted 5.15.170-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 __kvm_memslots include/linux/kvm_host.h:878 [inline]
 kvm_vcpu_memslots+0x1b7/0x200 include/linux/kvm_host.h:892
 kvm_vcpu_gfn_to_memslot+0x2b/0x390 virt/kvm/kvm_main.c:2158
 kvm_vcpu_unmap+0x5d/0x80 virt/kvm/kvm_main.c:2773
 nested_vmx_vmexit+0x1476/0x2b70 arch/x86/kvm/vmx/nested.c:4662
 vmx_leave_nested+0x7d/0xb0 arch/x86/kvm/vmx/nested.c:6322
 kvm_leave_nested arch/x86/kvm/x86.c:618 [inline]
 kvm_vcpu_ioctl_x86_set_vcpu_events+0x8d8/0x10e0 arch/x86/kvm/x86.c:4810
 kvm_arch_vcpu_ioctl+0x120e/0x1d40 arch/x86/kvm/x86.c:5295
 kvm_vcpu_ioctl+0x6db/0xcf0 virt/kvm/kvm_main.c:4050
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl+0xf1/0x160 fs/ioctl.c:860
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fcc815ff5f9
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:00007ffcbc2905e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffcbc2907b8 RCX: 00007fcc815ff5f9
RDX: 0000000020000180 RSI: 000000004040aea0 RDI: 0000000000000005
RBP: 00007fcc81672610 R08: 00007ffcbc2907b8 R09: 00007ffcbc2907b8
R10: