{ "BPF_ATOMIC bounds propagation, mem->reg", .insns = { /* a = 0; */ /* * Note this is implemented with two separate instructions, * where you might think one would suffice: * * BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0), * * This is because BPF_ST_MEM doesn't seem to set the stack slot * type to 0 when storing an immediate. */ BPF_MOV64_IMM(BPF_REG_0, 0), BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8), /* b = atomic_fetch_add(&a, 1); */ BPF_MOV64_IMM(BPF_REG_1, 1), BPF_ATOMIC_OP(BPF_DW, BPF_ADD | BPF_FETCH, BPF_REG_10, BPF_REG_1, -8), /* Verifier should be able to tell that this infinite loop isn't reachable. */ /* if (b) while (true) continue; */ BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, -1), BPF_EXIT_INSN(), }, .result = ACCEPT, .result_unpriv = REJECT, .errstr_unpriv = "back-edge", },