CVE-2025-23141

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> KVM: x86: Acquire SRCU in KVM_GET_MP_STATE to protect guest memory accesses<br /> <br /> Acquire a lock on kvm-&gt;srcu when userspace is getting MP state to handle a<br /> rather extreme edge case where "accepting" APIC events, i.e. processing<br /> pending INIT or SIPI, can trigger accesses to guest memory. If the vCPU<br /> is in L2 with INIT *and* a TRIPLE_FAULT request pending, then getting MP<br /> state will trigger a nested VM-Exit by way of -&gt;check_nested_events(), and<br /> emuating the nested VM-Exit can access guest memory.<br /> <br /> The splat was originally hit by syzkaller on a Google-internal kernel, and<br /> reproduced on an upstream kernel by hacking the triple_fault_event_test<br /> selftest to stuff a pending INIT, store an MSR on VM-Exit (to generate a<br /> memory access on VMX), and do vcpu_mp_state_get() to trigger the scenario.<br /> <br /> =============================<br /> WARNING: suspicious RCU usage<br /> 6.14.0-rc3-b112d356288b-vmx/pi_lockdep_false_pos-lock #3 Not tainted<br /> -----------------------------<br /> include/linux/kvm_host.h:1058 suspicious rcu_dereference_check() usage!<br /> <br /> other info that might help us debug this:<br /> <br /> rcu_scheduler_active = 2, debug_locks = 1<br /> 1 lock held by triple_fault_ev/1256:<br /> #0: ffff88810df5a330 (&amp;vcpu-&gt;mutex){+.+.}-{4:4}, at: kvm_vcpu_ioctl+0x8b/0x9a0 [kvm]<br /> <br /> stack backtrace:<br /> CPU: 11 UID: 1000 PID: 1256 Comm: triple_fault_ev Not tainted 6.14.0-rc3-b112d356288b-vmx #3<br /> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015<br /> Call Trace:<br /> <br /> dump_stack_lvl+0x7f/0x90<br /> lockdep_rcu_suspicious+0x144/0x190<br /> kvm_vcpu_gfn_to_memslot+0x156/0x180 [kvm]<br /> kvm_vcpu_read_guest+0x3e/0x90 [kvm]<br /> read_and_check_msr_entry+0x2e/0x180 [kvm_intel]<br /> __nested_vmx_vmexit+0x550/0xde0 [kvm_intel]<br /> kvm_check_nested_events+0x1b/0x30 [kvm]<br /> kvm_apic_accept_events+0x33/0x100 [kvm]<br /> kvm_arch_vcpu_ioctl_get_mpstate+0x30/0x1d0 [kvm]<br /> kvm_vcpu_ioctl+0x33e/0x9a0 [kvm]<br /> __x64_sys_ioctl+0x8b/0xb0<br /> do_syscall_64+0x6c/0x170<br /> entry_SYSCALL_64_after_hwframe+0x4b/0x53<br />