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| author | Kumar Kartikeya Dwivedi <memxor@gmail.com> | 2026-09-04 10:43:19 +0200 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-09-04 07:58:36 -0700 |
| commit | 6668ed271eaefaa63e686bdfbedaeb7b8e492722 (patch) | |
| tree | 58e8288fead484f6755ad0815fc74c3742663761 /arch/riscv/kvm/trace.h | |
| download | linux-stable-6668ed271eaefaa63e686bdfbedaeb7b8e492722.tar.gz linux-stable-6668ed271eaefaa63e686bdfbedaeb7b8e492722.zip | |
selftests/bpf: Reject graph kptr use after RCU unlockgrafted
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 <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'arch/riscv/kvm/trace.h')
| -rw-r--r-- | arch/riscv/kvm/trace.h | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/arch/riscv/kvm/trace.h b/arch/riscv/kvm/trace.h new file mode 100644 index 000000000..3d54175d8 --- /dev/null +++ b/arch/riscv/kvm/trace.h @@ -0,0 +1,67 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Tracepoints for RISC-V KVM + * + * Copyright 2024 Beijing ESWIN Computing Technology Co., Ltd. + * + */ +#if !defined(_TRACE_KVM_H) || defined(TRACE_HEADER_MULTI_READ) +#define _TRACE_KVM_H + +#include <linux/tracepoint.h> + +#undef TRACE_SYSTEM +#define TRACE_SYSTEM kvm + +TRACE_EVENT(kvm_entry, + TP_PROTO(struct kvm_vcpu *vcpu), + TP_ARGS(vcpu), + + TP_STRUCT__entry( + __field(unsigned long, pc) + ), + + TP_fast_assign( + __entry->pc = vcpu->arch.guest_context.sepc; + ), + + TP_printk("PC: 0x016%lx", __entry->pc) +); + +TRACE_EVENT(kvm_exit, + TP_PROTO(struct kvm_cpu_trap *trap), + TP_ARGS(trap), + + TP_STRUCT__entry( + __field(unsigned long, sepc) + __field(unsigned long, scause) + __field(unsigned long, stval) + __field(unsigned long, htval) + __field(unsigned long, htinst) + ), + + TP_fast_assign( + __entry->sepc = trap->sepc; + __entry->scause = trap->scause; + __entry->stval = trap->stval; + __entry->htval = trap->htval; + __entry->htinst = trap->htinst; + ), + + TP_printk("SEPC:0x%lx, SCAUSE:0x%lx, STVAL:0x%lx, HTVAL:0x%lx, HTINST:0x%lx", + __entry->sepc, + __entry->scause, + __entry->stval, + __entry->htval, + __entry->htinst) +); + +#endif /* _TRACE_RSICV_KVM_H */ + +#undef TRACE_INCLUDE_PATH +#define TRACE_INCLUDE_PATH . +#undef TRACE_INCLUDE_FILE +#define TRACE_INCLUDE_FILE trace + +/* This part must be outside protection */ +#include <trace/define_trace.h> |