[PATCH bpf v3 2/2] selftests: bpf: test that dead ldx_w insns are accepted

[Ilya Leoshkevich <iii@xxxxxxxxxxxxx>]

Prevent regressions related to zero-extension metadata handling during
dead code sanitization.

Signed-off-by: Ilya Leoshkevich <iii@xxxxxxxxxxxxx>
---
 tools/testing/selftests/bpf/verifier/dead_code.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/testing/selftests/bpf/verifier/dead_code.c b/tools/testing/selftests/bpf/verifier/dead_code.c
index 2c8935b3e65d..ee454327e5c6 100644
--- a/tools/testing/selftests/bpf/verifier/dead_code.c
+++ b/tools/testing/selftests/bpf/verifier/dead_code.c
@@ -159,3 +159,15 @@
 	.result = ACCEPT,
 	.retval = 2,
 },
+{
+	"dead code: zero extension",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -4),
+	BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 0, 1),
+	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_10, -4),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.retval = 0,
+},
-- 
2.31.1