selftests/bpf: Add regression test for pruning fix

Add a test to ensure we do mark_chain_precision for the argument type
ARG_CONST_ALLOC_SIZE_OR_ZERO. For other argument types, this was already
done, but propagation for missing for this case. Without the fix, this
test case loads successfully.

Signed-off-by: Kumar Kartikeya Dwivedi <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Alexei Starovoitov <[e-mail]>

tools/testing/selftests/bpf/verifier/precise.c

···
 	.result = VERBOSE_ACCEPT,
 	.retval = -1,
 },
+{
+	"precise: mark_chain_precision for ARG_CONST_ALLOC_SIZE_OR_ZERO",
+	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_4, BPF_REG_1, offsetof(struct xdp_md, ingress_ifindex)),
+	BPF_LD_MAP_FD(BPF_REG_6, 0),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
+	BPF_MOV64_IMM(BPF_REG_2, 1),
+	BPF_MOV64_IMM(BPF_REG_3, 0),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_4, 0, 1),
+	BPF_MOV64_IMM(BPF_REG_2, 0x1000),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_reserve),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_EXIT_INSN(),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_0, 42),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_ringbuf_submit),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.fixup_map_ringbuf = { 1 },
+	.prog_type = BPF_PROG_TYPE_XDP,
+	.flags = BPF_F_TEST_STATE_FREQ,
+	.errstr = "invalid access to memory, mem_size=1 off=42 size=8",
+	.result = REJECT,
+},