1 {
2 "BPF_ATOMIC bounds propagation, mem->reg",
3 .insns = {
4 /* a = 0; */
5 /*
6 * Note this is implemented with two separate instructions,
7 * where you might think one would suffice:
8 *
9 * BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
10 *
11 * This is because BPF_ST_MEM doesn't seem to set the stack slot
12 * type to 0 when storing an immediate.
13 */
14 BPF_MOV64_IMM(BPF_REG_0, 0),
15 BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
16 /* b = atomic_fetch_add(&a, 1); */
17 BPF_MOV64_IMM(BPF_REG_1, 1),
18 BPF_ATOMIC_OP(BPF_DW, BPF_ADD | BPF_FETCH, BPF_REG_10, BPF_REG_1, -8),
19 /* Verifier should be able to tell that this infinite loop isn't reachable. */
20 /* if (b) while (true) continue; */
21 BPF_JMP_IMM(BPF_JNE, BPF_REG_1, 0, -1),
22 BPF_EXIT_INSN(),
23 },
24 .result = ACCEPT,
25 .result_unpriv = REJECT,
26 .errstr_unpriv = "back-edge",
27 },
28
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