selftests/bpf: precision tracking tests

Add two tests to check that stack slot marking during backtracking
doesn't trigger 'spi > allocated_stack' warning.
One test is using BPF_ST insn. Another is using BPF_STX.

Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/tools/testing/selftests/bpf/verifier/precise.c b/tools/testing/selftests/bpf/verifier/precise.c
index a455a4a71f11a84898f1404be75b4d7102b39c51..02151f8c940f8561f345470ab7af0ccf525beb18 100644 (file)
--- a/tools/testing/selftests/bpf/verifier/precise.c
+++ b/tools/testing/selftests/bpf/verifier/precise.c
@@ -140,3 +140,55 @@
        .errstr = "!read_ok",
        .result = REJECT,
 },
+{
+       "precise: ST insn causing spi > allocated_stack",
+       .insns = {
+       BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),
+       BPF_JMP_IMM(BPF_JNE, BPF_REG_3, 123, 0),
+       BPF_ST_MEM(BPF_DW, BPF_REG_3, -8, 0),
+       BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
+       BPF_MOV64_IMM(BPF_REG_0, -1),
+       BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_0, 0),
+       BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_XDP,
+       .flags = BPF_F_TEST_STATE_FREQ,
+       .errstr = "5: (2d) if r4 > r0 goto pc+0\
+       last_idx 5 first_idx 5\
+       parent didn't have regs=10 stack=0 marks\
+       last_idx 4 first_idx 2\
+       regs=10 stack=0 before 4\
+       regs=10 stack=0 before 3\
+       regs=0 stack=1 before 2\
+       last_idx 5 first_idx 5\
+       parent didn't have regs=1 stack=0 marks",
+       .result = VERBOSE_ACCEPT,
+       .retval = -1,
+},
+{
+       "precise: STX insn causing spi > allocated_stack",
+       .insns = {
+       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
+       BPF_MOV64_REG(BPF_REG_3, BPF_REG_10),
+       BPF_JMP_IMM(BPF_JNE, BPF_REG_3, 123, 0),
+       BPF_STX_MEM(BPF_DW, BPF_REG_3, BPF_REG_0, -8),
+       BPF_LDX_MEM(BPF_DW, BPF_REG_4, BPF_REG_10, -8),
+       BPF_MOV64_IMM(BPF_REG_0, -1),
+       BPF_JMP_REG(BPF_JGT, BPF_REG_4, BPF_REG_0, 0),
+       BPF_EXIT_INSN(),
+       },
+       .prog_type = BPF_PROG_TYPE_XDP,
+       .flags = BPF_F_TEST_STATE_FREQ,
+       .errstr = "last_idx 6 first_idx 6\
+       parent didn't have regs=10 stack=0 marks\
+       last_idx 5 first_idx 3\
+       regs=10 stack=0 before 5\
+       regs=10 stack=0 before 4\
+       regs=0 stack=1 before 3\
+       last_idx 6 first_idx 6\
+       parent didn't have regs=1 stack=0 marks\
+       last_idx 5 first_idx 3\
+       regs=1 stack=0 before 5",
+       .result = VERBOSE_ACCEPT,
+       .retval = -1,
+},