Merge branch 'bpf-bounded-loops'

Alexei Starovoitov says:

====================
v2->v3: fixed issues in backtracking pointed out by Andrii.
The next step is to add a lot more tests for backtracking.

v1->v2: addressed Andrii's feedback.

this patch set introduces verifier support for bounded loops and
adds several other improvements.
Ideally they would be introduced one at a time,
but to support bounded loop the verifier needs to 'step back'
in the patch 1. That patch introduces tracking of spill/fill
of constants through the stack. Though it's a useful feature
it hurts cilium tests.
Patch 3 introduces another feature by extending is_branch_taken
logic to 'if rX op rY' conditions. This feature is also
necessary to support bounded loops.
Then patch 4 adds support for the loops while adding
key heuristics with jmp_processed.
Introduction of parentage chain of verifier states in patch 4
allows patch 9 to add backtracking of precise scalar registers
which finally resolves degradation from patch 1.

The end result is much faster verifier for existing programs
and new support for loops.
See patch 8 for many kinds of loops that are now validated.
Patch 9 is the most tricky one and could be rewritten with
a different algorithm in the future.
====================

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

5 files changed, 198 insertions, 27 deletions

diff --git a/tools/testing/selftests/bpf/verifier/calls.c b/tools/testing/selftests/bpf/verifier/calls.c
index 9093a8f64dc6..2d752c4f8d9d 100644
--- a/tools/testing/selftests/bpf/verifier/calls.c
+++ b/tools/testing/selftests/bpf/verifier/calls.c
@@ -215,9 +215,11 @@
 	BPF_MOV64_IMM(BPF_REG_0, 3),
 	BPF_JMP_IMM(BPF_JA, 0, 0, -6),
 	},
-	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
-	.errstr = "back-edge from insn",
-	.result = REJECT,
+	.prog_type = BPF_PROG_TYPE_SOCKET_FILTER,
+	.errstr_unpriv = "back-edge from insn",
+	.result_unpriv = REJECT,
+	.result = ACCEPT,
+	.retval = 1,
 },
 {
 	"calls: conditional call 4",
@@ -250,22 +252,24 @@
 	BPF_MOV64_IMM(BPF_REG_0, 3),
 	BPF_EXIT_INSN(),
 	},
-	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
-	.errstr = "back-edge from insn",
-	.result = REJECT,
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	.result = ACCEPT,
+	.retval = 1,
 },
 {
 	"calls: conditional call 6",
 	.insns = {
+	BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),
+	BPF_MOV64_REG(BPF_REG_1, BPF_REG_6),
 	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 2),
-	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -2),
+	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, -3),
 	BPF_EXIT_INSN(),
 	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
 		    offsetof(struct __sk_buff, mark)),
 	BPF_EXIT_INSN(),
 	},
-	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
-	.errstr = "back-edge from insn",
+	.prog_type = BPF_PROG_TYPE_SCHED_CLS,
+	.errstr = "infinite loop detected",
 	.result = REJECT,
 },
 {
diff --git a/tools/testing/selftests/bpf/verifier/cfg.c b/tools/testing/selftests/bpf/verifier/cfg.c
index 349c0862fb4c..4eb76ed739ce 100644
--- a/tools/testing/selftests/bpf/verifier/cfg.c
+++ b/tools/testing/selftests/bpf/verifier/cfg.c
@@ -41,7 +41,8 @@
 	BPF_JMP_IMM(BPF_JA, 0, 0, -1),
 	BPF_EXIT_INSN(),
 	},
-	.errstr = "back-edge",
+	.errstr = "unreachable insn 1",
+	.errstr_unpriv = "back-edge",
 	.result = REJECT,
 },
 {
@@ -53,18 +54,20 @@
 	BPF_JMP_IMM(BPF_JA, 0, 0, -4),
 	BPF_EXIT_INSN(),
 	},
-	.errstr = "back-edge",
+	.errstr = "unreachable insn 4",
+	.errstr_unpriv = "back-edge",
 	.result = REJECT,
 },
 {
 	"conditional loop",
 	.insns = {
-	BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
+	BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
 	BPF_MOV64_REG(BPF_REG_2, BPF_REG_0),
 	BPF_MOV64_REG(BPF_REG_3, BPF_REG_0),
 	BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, -3),
 	BPF_EXIT_INSN(),
 	},
-	.errstr = "back-edge",
+	.errstr = "infinite loop detected",
+	.errstr_unpriv = "back-edge",
 	.result = REJECT,
 },
diff --git a/tools/testing/selftests/bpf/verifier/direct_packet_access.c b/tools/testing/selftests/bpf/verifier/direct_packet_access.c
index d5c596fdc4b9..2c5fbe7bcd27 100644
--- a/tools/testing/selftests/bpf/verifier/direct_packet_access.c
+++ b/tools/testing/selftests/bpf/verifier/direct_packet_access.c
@@ -511,7 +511,8 @@
 		    offsetof(struct __sk_buff, data)),
 	BPF_LDX_MEM(BPF_W, BPF_REG_3, BPF_REG_1,
 		    offsetof(struct __sk_buff, data_end)),
-	BPF_MOV64_IMM(BPF_REG_0, 0xffffffff),
+	BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_1,
+		    offsetof(struct __sk_buff, mark)),
 	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
 	BPF_ALU64_IMM(BPF_AND, BPF_REG_0, 0xffff),
diff --git a/tools/testing/selftests/bpf/verifier/helper_access_var_len.c b/tools/testing/selftests/bpf/verifier/helper_access_var_len.c
index 1f39d845c64f..67ab12410050 100644
--- a/tools/testing/selftests/bpf/verifier/helper_access_var_len.c
+++ b/tools/testing/selftests/bpf/verifier/helper_access_var_len.c
@@ -29,9 +29,9 @@
 {
 	"helper access to variable memory: stack, bitwise AND, zero included",
 	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, 8),
 	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
-	BPF_MOV64_IMM(BPF_REG_2, 16),
 	BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
 	BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 64),
@@ -46,9 +46,9 @@
 {
 	"helper access to variable memory: stack, bitwise AND + JMP, wrong max",
 	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, 8),
 	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
-	BPF_MOV64_IMM(BPF_REG_2, 16),
 	BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
 	BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 65),
@@ -122,9 +122,9 @@
 {
 	"helper access to variable memory: stack, JMP, bounds + offset",
 	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, 8),
 	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
-	BPF_MOV64_IMM(BPF_REG_2, 16),
 	BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
 	BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 64, 5),
@@ -143,9 +143,9 @@
 {
 	"helper access to variable memory: stack, JMP, wrong max",
 	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, 8),
 	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
-	BPF_MOV64_IMM(BPF_REG_2, 16),
 	BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
 	BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 65, 4),
@@ -163,9 +163,9 @@
 {
 	"helper access to variable memory: stack, JMP, no max check",
 	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, 8),
 	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
-	BPF_MOV64_IMM(BPF_REG_2, 16),
 	BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
 	BPF_MOV64_IMM(BPF_REG_4, 0),
@@ -183,9 +183,9 @@
 {
 	"helper access to variable memory: stack, JMP, no min check",
 	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, 8),
 	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
-	BPF_MOV64_IMM(BPF_REG_2, 16),
 	BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
 	BPF_JMP_IMM(BPF_JGT, BPF_REG_2, 64, 3),
@@ -201,9 +201,9 @@
 {
 	"helper access to variable memory: stack, JMP (signed), no min check",
 	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, 8),
 	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
-	BPF_MOV64_IMM(BPF_REG_2, 16),
 	BPF_STX_MEM(BPF_DW, BPF_REG_1, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, -128),
 	BPF_JMP_IMM(BPF_JSGT, BPF_REG_2, 64, 3),
@@ -244,6 +244,7 @@
 {
 	"helper access to variable memory: map, JMP, wrong max",
 	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 8),
 	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),
@@ -251,7 +252,7 @@
 	BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
 	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 10),
 	BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
-	BPF_MOV64_IMM(BPF_REG_2, sizeof(struct test_val)),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_6),
 	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
 	BPF_JMP_IMM(BPF_JSGT, BPF_REG_2, sizeof(struct test_val) + 1, 4),
@@ -262,7 +263,7 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_48b = { 3 },
+	.fixup_map_hash_48b = { 4 },
 	.errstr = "invalid access to map value, value_size=48 off=0 size=49",
 	.result = REJECT,
 	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
@@ -296,6 +297,7 @@
 {
 	"helper access to variable memory: map adjusted, JMP, wrong max",
 	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_6, BPF_REG_1, 8),
 	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),
@@ -304,7 +306,7 @@
 	BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 11),
 	BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, 20),
-	BPF_MOV64_IMM(BPF_REG_2, sizeof(struct test_val)),
+	BPF_MOV64_REG(BPF_REG_2, BPF_REG_6),
 	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
 	BPF_JMP_IMM(BPF_JSGT, BPF_REG_2, sizeof(struct test_val) - 19, 4),
@@ -315,7 +317,7 @@
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
 	},
-	.fixup_map_hash_48b = { 3 },
+	.fixup_map_hash_48b = { 4 },
 	.errstr = "R1 min value is outside of the array range",
 	.result = REJECT,
 	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
@@ -337,8 +339,8 @@
 {
 	"helper access to variable memory: size > 0 not allowed on NULL (ARG_PTR_TO_MEM_OR_NULL)",
 	.insns = {
+	BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 0),
 	BPF_MOV64_IMM(BPF_REG_1, 0),
-	BPF_MOV64_IMM(BPF_REG_2, 1),
 	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
 	BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 64),
@@ -562,6 +564,7 @@
 {
 	"helper access to variable memory: 8 bytes leak",
 	.insns = {
+	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_1, 8),
 	BPF_MOV64_REG(BPF_REG_1, BPF_REG_10),
 	BPF_ALU64_IMM(BPF_ADD, BPF_REG_1, -64),
 	BPF_MOV64_IMM(BPF_REG_0, 0),
@@ -572,7 +575,6 @@
 	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -24),
 	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -16),
 	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
-	BPF_MOV64_IMM(BPF_REG_2, 1),
 	BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_2, -128),
 	BPF_LDX_MEM(BPF_DW, BPF_REG_2, BPF_REG_10, -128),
 	BPF_ALU64_IMM(BPF_AND, BPF_REG_2, 63),
diff --git a/tools/testing/selftests/bpf/verifier/loops1.c b/tools/testing/selftests/bpf/verifier/loops1.c
new file mode 100644
index 000000000000..5e980a5ab69d
--- /dev/null
+++ b/tools/testing/selftests/bpf/verifier/loops1.c
@@ -0,0 +1,161 @@
+{
+	"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, 3),
+	BPF_JMP_IMM(BPF_JLT, BPF_REG_0, 20, -2),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+},
+{
+	"bounded loop, count from positive unknown to 4",
+	.insns = {
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
+	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(),
+	},
+	.result = ACCEPT,
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.retval = 4,
+},
+{
+	"bounded loop, count from totally unknown to 4",
+	.insns = {
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
+	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,
+},
+{
+	"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 = ACCEPT,
+	.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 = REJECT,
+	.errstr = "back-edge",
+	.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_IMM(BPF_REG_6, 0),
+	BPF_ALU64_IMM(BPF_ADD, BPF_REG_6, 1),
+	BPF_JMP_IMM(BPF_JGT, BPF_REG_6, 10000, 2),
+	BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0, BPF_FUNC_get_prandom_u32),
+	BPF_JMP_A(-4),
+	BPF_EXIT_INSN(),
+	},
+	.result = ACCEPT,
+	.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 = "program is too large",
+	.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 = "back-edge",
+	.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 detected",
+	.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 detected",
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+},