From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- arch/powerpc/kvm/timing.h | 95 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 95 insertions(+) create mode 100644 arch/powerpc/kvm/timing.h (limited to 'arch/powerpc/kvm/timing.h') diff --git a/arch/powerpc/kvm/timing.h b/arch/powerpc/kvm/timing.h new file mode 100644 index 000000000..14b0e23f6 --- /dev/null +++ b/arch/powerpc/kvm/timing.h @@ -0,0 +1,95 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * + * Copyright IBM Corp. 2008 + * + * Authors: Christian Ehrhardt + */ + +#ifndef __POWERPC_KVM_EXITTIMING_H__ +#define __POWERPC_KVM_EXITTIMING_H__ + +#include + +#ifdef CONFIG_KVM_EXIT_TIMING +void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu); +void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu); +int kvmppc_create_vcpu_debugfs_e500(struct kvm_vcpu *vcpu, + struct dentry *debugfs_dentry); + +static inline void kvmppc_set_exit_type(struct kvm_vcpu *vcpu, int type) +{ + vcpu->arch.last_exit_type = type; +} + +#else +/* if exit timing is not configured there is no need to build the c file */ +static inline void kvmppc_init_timing_stats(struct kvm_vcpu *vcpu) {} +static inline void kvmppc_update_timing_stats(struct kvm_vcpu *vcpu) {} +static inline int kvmppc_create_vcpu_debugfs_e500(struct kvm_vcpu *vcpu, + struct dentry *debugfs_dentry) +{ + return 0; +} +static inline void kvmppc_set_exit_type(struct kvm_vcpu *vcpu, int type) {} +#endif /* CONFIG_KVM_EXIT_TIMING */ + +/* account the exit in kvm_stats */ +static inline void kvmppc_account_exit_stat(struct kvm_vcpu *vcpu, int type) +{ + /* type has to be known at build time for optimization */ + BUILD_BUG_ON(!__builtin_constant_p(type)); + switch (type) { + case EXT_INTR_EXITS: + vcpu->stat.ext_intr_exits++; + break; + case DEC_EXITS: + vcpu->stat.dec_exits++; + break; + case EMULATED_INST_EXITS: + vcpu->stat.emulated_inst_exits++; + break; + case DSI_EXITS: + vcpu->stat.dsi_exits++; + break; + case ISI_EXITS: + vcpu->stat.isi_exits++; + break; + case SYSCALL_EXITS: + vcpu->stat.syscall_exits++; + break; + case DTLB_REAL_MISS_EXITS: + vcpu->stat.dtlb_real_miss_exits++; + break; + case DTLB_VIRT_MISS_EXITS: + vcpu->stat.dtlb_virt_miss_exits++; + break; + case MMIO_EXITS: + vcpu->stat.mmio_exits++; + break; + case ITLB_REAL_MISS_EXITS: + vcpu->stat.itlb_real_miss_exits++; + break; + case ITLB_VIRT_MISS_EXITS: + vcpu->stat.itlb_virt_miss_exits++; + break; + case SIGNAL_EXITS: + vcpu->stat.signal_exits++; + break; + case DBELL_EXITS: + vcpu->stat.dbell_exits++; + break; + case GDBELL_EXITS: + vcpu->stat.gdbell_exits++; + break; + } +} + +/* wrapper to set exit time and account for it in kvm_stats */ +static inline void kvmppc_account_exit(struct kvm_vcpu *vcpu, int type) +{ + kvmppc_set_exit_type(vcpu, type); + kvmppc_account_exit_stat(vcpu, type); +} + +#endif /* __POWERPC_KVM_EXITTIMING_H__ */ -- cgit v1.3.1