Subject: [PATCH bpf-next 4/4] selftests/bpf: add precision tracking test

From: Alexei Starovoitov <[email-masked]>
Date: Thu, 22 Aug 2019 22:52:15 -0700

Copy-paste of existing test
"calls: cross frame pruning - liveness propagation"
but ran with different parentage chain heuristic
which stresses different path in precision tracking logic.

Signed-off-by: Alexei Starovoitov <[email-masked]>
---
This test will be failing without this fix
https://patchwork.ozlabs.org/patch/1151172/
---
 .../testing/selftests/bpf/verifier/precise.c  | 25 +++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/tools/testing/selftests/bpf/verifier/precise.c b/tools/testing/selftests/bpf/verifier/precise.c
index a20953c23721..a455a4a71f11 100644
--- a/tools/testing/selftests/bpf/verifier/precise.c
+++ b/tools/testing/selftests/bpf/verifier/precise.c
@@ -115,3 +115,28 @@
 	regs=300 stack=0 before 17\
 	parent already had regs=0 stack=0 marks",
 },
+{
+	"precise: cross frame pruning",
+	.insns = {
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
+	BPF_MOV64_IMM(BPF_REG_8, 0),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_MOV64_IMM(BPF_REG_8, 1),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
+	BPF_MOV64_IMM(BPF_REG_9, 0),
+	BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 0, 1),
+	BPF_MOV64_IMM(BPF_REG_9, 1),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 4),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_8, 1, 1),
+	BPF_LDX_MEM(BPF_B, BPF_REG_1, BPF_REG_2, 0),
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_XDP,
+	.flags = BPF_F_TEST_STATE_FREQ,
+	.errstr = "!read_ok",
+	.result = REJECT,
+},
-- 
2.20.0