Mainly consists of tests that broke (or I expected to break) earlier
 versions of the bounded-loop handling.
Also updated some existing tests to deal with changed error messages,
 programs now being accepted etc.

Signed-off-by: Edward Cree <ec...@solarflare.com>
---
 tools/testing/selftests/bpf/test_verifier.c | 198 +++++++++++++++++++++++++++-
 1 file changed, 191 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_verifier.c 
b/tools/testing/selftests/bpf/test_verifier.c
index 722a16b2e9c4..fda35a5a0ff9 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -9338,7 +9338,7 @@ static struct bpf_test tests[] = {
                        BPF_EXIT_INSN(),
                },
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
-               .errstr = "frames is too deep",
+               .errstr = "recursive call",
                .result = REJECT,
        },
        {
@@ -9389,8 +9389,8 @@ static struct bpf_test tests[] = {
                        BPF_JMP_IMM(BPF_JA, 0, 0, -6),
                },
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
-               .errstr = "back-edge from insn",
-               .result = REJECT,
+               .result = ACCEPT,
+               .retval = 1,
        },
        {
                "calls: conditional call 4",
@@ -9424,8 +9424,8 @@ static struct bpf_test tests[] = {
                        BPF_EXIT_INSN(),
                },
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
-               .errstr = "back-edge from insn",
-               .result = REJECT,
+               .result = ACCEPT,
+               .retval = 1,
        },
        {
                "calls: conditional call 6",
@@ -9666,7 +9666,7 @@ static struct bpf_test tests[] = {
                        BPF_EXIT_INSN(),
                },
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
-               .errstr = "frames is too deep",
+               .errstr = "recursive call",
                .result = REJECT,
        },
        {
@@ -9678,7 +9678,7 @@ static struct bpf_test tests[] = {
                        BPF_EXIT_INSN(),
                },
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
-               .errstr = "frames is too deep",
+               .errstr = "recursive call",
                .result = REJECT,
        },
        {
@@ -11135,6 +11135,190 @@ static struct bpf_test tests[] = {
                .result = REJECT,
                .prog_type = BPF_PROG_TYPE_TRACEPOINT,
        },
+       {
+               "bounded loop, count to 4",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 4, -2),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+               .retval = 4,
+       },
+       {
+               "bounded loop, count to 20",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 20, -2),
+                       BPF_EXIT_INSN(),
+               },
+               .result = REJECT,
+               .errstr = "r0 is increasing too slowly",
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       },
+       {
+               "bounded loop, count from positive unknown to 4",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                       BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+                       BPF_LD_MAP_FD(BPF_REG_1, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+                       BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
+                       BPF_JMP_IMM(BPF_JSLT, BPF_REG_0, 0, 2),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 4, -2),
+                       BPF_EXIT_INSN(),
+               },
+               .fixup_map1 = { 3 },
+               .result = ACCEPT,
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+               .retval = 4,
+       },
+       {
+               "bounded loop, count from totally unknown to 4",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                       BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+                       BPF_LD_MAP_FD(BPF_REG_1, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 3),
+                       BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 4, -2),
+                       BPF_EXIT_INSN(),
+               },
+               .fixup_map1 = { 3 },
+               .result = REJECT,
+               .errstr = "r0 is not increasing",
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       },
+       {
+               "bounded loop, count to 4 with equality",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_JMP_IMM(BPF_JNE, BPF_REG_0, 4, -2),
+                       BPF_EXIT_INSN(),
+               },
+               .result = REJECT,
+               .errstr = "loop with this opcode not supported",
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       },
+       {
+               "bounded loop, start in the middle",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_JMP_A(1),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 4, -2),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+               .retval = 4,
+       },
+       {
+               "bounded loop containing a forward jump",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_JMP_REG(BPF_JEQ, BPF_REG_0, BPF_REG_0, 0),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 4, -3),
+                       BPF_EXIT_INSN(),
+               },
+               .result = ACCEPT,
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+               .retval = 4,
+       },
+       {
+               "bounded loop that jumps out rather than in",
+               .insns = {
+                       BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
+                       BPF_ST_MEM(BPF_DW, BPF_REG_2, 0, 0),
+                       BPF_LD_MAP_FD(BPF_REG_1, 0),
+                       BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
+                       BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 4),
+                       BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_0, 0),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 4, 1),
+                       BPF_JMP_A(-3),
+                       BPF_EXIT_INSN(),
+               },
+               .fixup_map1 = { 3 },
+               .result = REJECT,
+               .errstr = "loop on conditional fallthrough",
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       },
+       {
+               "infinite loop after a conditional jump",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_0, 5),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 4, 2),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_JMP_A(-2),
+                       BPF_EXIT_INSN(),
+               },
+               .result = REJECT,
+               .errstr = "back-edge from insn 3 to 2",
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       },
+       {
+               "bounded recursion",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_1, 0),
+                       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
+                       BPF_EXIT_INSN(),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 1),
+                       BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_1, 4, 1),
+                       BPF_EXIT_INSN(),
+                       BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -5),
+                       BPF_EXIT_INSN(),
+               },
+               .result = REJECT,
+               .errstr = "recursive call",
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       },
+       {
+               "infinite loop in two jumps",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_JMP_A(0),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 4, -2),
+                       BPF_EXIT_INSN(),
+               },
+               .result = REJECT,
+               .errstr = "loop variable r0 is not increasing",
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       },
+       {
+               "infinite loop: three-jump trick",
+               .insns = {
+                       BPF_MOV64_IMM(BPF_REG_0, 0),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 1),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 2, 1),
+                       BPF_EXIT_INSN(),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 1),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 2, 1),
+                       BPF_EXIT_INSN(),
+                       BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+                       BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 1),
+                       BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 2, -11),
+                       BPF_EXIT_INSN(),
+               },
+               .result = REJECT,
+               .errstr = "loop from insn 11 to 1 ceased to be bounded",
+               .prog_type = BPF_PROG_TYPE_TRACEPOINT,
+       },
 };
 
 static int probe_filter_length(const struct bpf_insn *fp)

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