From: Ilya Leoshkevich <iii@linux.ibm.com>
Date: Thu, 12 Aug 2021 15:18:11 +0000 (+0200)
Subject: selftests, bpf: Test that dead ldx_w insns are accepted
X-Git-Tag: v5.14-rc7~20^2~3^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3776f3517ed94d40ff0e3851d7ce2ce17b63099f;p=thirdparty%2Fkernel%2Flinux.git

selftests, bpf: Test that dead ldx_w insns are accepted

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

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210812151811.184086-3-iii@linux.ibm.com
---

diff --git a/tools/testing/selftests/bpf/verifier/dead_code.c b/tools/testing/selftests/bpf/verifier/dead_code.c
index 2c8935b3e65da..ee454327e5c60 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,
+},