[PATCH bpf-next 2/2] selftests/bpf: test case for invalid call stack in dead code

[Paul Chaignon]

This patch adds a test case with an excessive number of call stack frames
in dead code.

Signed-off-by: Paul Chaignon <paul.chaig...@orange.com>
Tested-by: Xiao Han <xiao....@orange.com>
---
 tools/testing/selftests/bpf/verifier/calls.c | 38 ++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/tools/testing/selftests/bpf/verifier/calls.c 
b/tools/testing/selftests/bpf/verifier/calls.c
index 4004891afa9c..ff147fcda82b 100644
--- a/tools/testing/selftests/bpf/verifier/calls.c
+++ b/tools/testing/selftests/bpf/verifier/calls.c
@@ -907,6 +907,44 @@
        .errstr = "call stack",
        .result = REJECT,
 },
+{
+       "calls: stack depth check in dead code",
+       .insns = {
+       /* main */
+       BPF_MOV64_IMM(BPF_REG_1, 0),
+       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call A */
+       BPF_EXIT_INSN(),
+       /* A */
+       BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 1),
+       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 2), /* call B */
+       BPF_MOV64_IMM(BPF_REG_0, 0),
+       BPF_EXIT_INSN(),
+       /* B */
+       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call C */
+       BPF_EXIT_INSN(),
+       /* C */
+       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call D */
+       BPF_EXIT_INSN(),
+       /* D */
+       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call E */
+       BPF_EXIT_INSN(),
+       /* E */
+       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call F */
+       BPF_EXIT_INSN(),
+       /* F */
+       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call G */
+       BPF_EXIT_INSN(),
+       /* G */
+       BPF_RAW_INSN(BPF_JMP|BPF_CALL, 0, 1, 0, 1), /* call H */
+       BPF_EXIT_INSN(),
+       /* H */
+       BPF_MOV64_IMM(BPF_REG_0, 0),
+       BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_XDP,
+       .errstr = "call stack",
+       .result = REJECT,
+},
 {
        "calls: spill into caller stack frame",
        .insns = {
-- 
2.17.1