| { |
| "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", |
| }, |
