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/arm/probes/decode-arm.h | 68 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) create mode 100644 arch/arm/probes/decode-arm.h (limited to 'arch/arm/probes/decode-arm.h') diff --git a/arch/arm/probes/decode-arm.h b/arch/arm/probes/decode-arm.h new file mode 100644 index 000000000..48989c2e1 --- /dev/null +++ b/arch/arm/probes/decode-arm.h @@ -0,0 +1,68 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * arch/arm/probes/decode-arm.h + * + * Copyright 2013 Linaro Ltd. + * Written by: David A. Long + */ + +#ifndef _ARM_KERNEL_PROBES_ARM_H +#define _ARM_KERNEL_PROBES_ARM_H + +#include "decode.h" + +enum probes_arm_action { + PROBES_PRELOAD_IMM, + PROBES_PRELOAD_REG, + PROBES_BRANCH_IMM, + PROBES_BRANCH_REG, + PROBES_MRS, + PROBES_CLZ, + PROBES_SATURATING_ARITHMETIC, + PROBES_MUL1, + PROBES_MUL2, + PROBES_SWP, + PROBES_LDRSTRD, + PROBES_LOAD, + PROBES_STORE, + PROBES_LOAD_EXTRA, + PROBES_STORE_EXTRA, + PROBES_MOV_IP_SP, + PROBES_DATA_PROCESSING_REG, + PROBES_DATA_PROCESSING_IMM, + PROBES_MOV_HALFWORD, + PROBES_SEV, + PROBES_WFE, + PROBES_SATURATE, + PROBES_REV, + PROBES_MMI, + PROBES_PACK, + PROBES_EXTEND, + PROBES_EXTEND_ADD, + PROBES_MUL_ADD_LONG, + PROBES_MUL_ADD, + PROBES_BITFIELD, + PROBES_BRANCH, + PROBES_LDMSTM, + NUM_PROBES_ARM_ACTIONS +}; + +void __kprobes simulate_bbl(probes_opcode_t opcode, + struct arch_probes_insn *asi, struct pt_regs *regs); +void __kprobes simulate_blx1(probes_opcode_t opcode, + struct arch_probes_insn *asi, struct pt_regs *regs); +void __kprobes simulate_blx2bx(probes_opcode_t opcode, + struct arch_probes_insn *asi, struct pt_regs *regs); +void __kprobes simulate_mrs(probes_opcode_t opcode, + struct arch_probes_insn *asi, struct pt_regs *regs); +void __kprobes simulate_mov_ipsp(probes_opcode_t opcode, + struct arch_probes_insn *asi, struct pt_regs *regs); + +extern const union decode_item probes_decode_arm_table[]; + +enum probes_insn arm_probes_decode_insn(probes_opcode_t, + struct arch_probes_insn *, bool emulate, + const union decode_action *actions, + const struct decode_checker *checkers[]); + +#endif -- cgit v1.3.1