Merge branch 'dead-code-elimination'

Jakub Kicinski says:

====================
This set adds support for complete removal of dead code.

Patch 3 contains all the code removal logic, patches 2 and 4
additionally optimize branches around and to dead code.

Patches 6 and 7 allow offload JITs to take advantage of the
optimization.  After a few small clean ups (8, 9, 10) nfp
support is added (11, 12).

Removing code directly in the verifier makes it easy to adjust
the relevant metadata (line info, subprogram info).  JITs for
code store constrained architectures would have hard time
performing such adjustments at JIT level.  Removing subprograms
or line info is very hard once BPF core finished the verification.
For user space to perform dead code removal it would have to perform
the execution simulation/analysis similar to what the verifier does.

v3:
 - fix uninitilized var warning in GCC 6 (buildbot).
v4:
 - simplify the linfo-keeping logic (Yonghong).  Instead of
   trying to figure out that we are removing first instruction
   of a subprogram, just always keep last dead line info, if
   first live instruction doesn't have one.
v5:
 - improve comments (Martin Lau).
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2 files changed, 549 insertions, 7 deletions

diff --git a/tools/testing/selftests/bpf/test_btf.c b/tools/testing/selftests/bpf/test_btf.c
index bfd92182533b..179f1d8ec5bf 100644
--- a/tools/testing/selftests/bpf/test_btf.c
+++ b/tools/testing/selftests/bpf/test_btf.c
@@ -4293,6 +4293,10 @@ static struct prog_info_raw_test {
 	__u32 line_info_rec_size;
 	__u32 nr_jited_ksyms;
 	bool expected_prog_load_failure;
+	__u32 dead_code_cnt;
+	__u32 dead_code_mask;
+	__u32 dead_func_cnt;
+	__u32 dead_func_mask;
 } info_raw_tests[] = {
 {
 	.descr = "func_type (main func + one sub)",
@@ -4719,6 +4723,369 @@ static struct prog_info_raw_test {
 	.expected_prog_load_failure = true,
 },
 
+{
+	.descr = "line_info (dead start)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0/* dead jmp */\0int a=1;\0int b=2;\0return a + b;\0return a + b;"),
+	.insns = {
+		BPF_JMP_IMM(BPF_JA, 0, 0, 0),
+		BPF_MOV64_IMM(BPF_REG_0, 1),
+		BPF_MOV64_IMM(BPF_REG_1, 2),
+		BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+		BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.func_info_cnt = 0,
+	.line_info = {
+		BPF_LINE_INFO_ENC(0, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(1, 0, NAME_TBD, 2, 9),
+		BPF_LINE_INFO_ENC(2, 0, NAME_TBD, 3, 8),
+		BPF_LINE_INFO_ENC(3, 0, NAME_TBD, 4, 7),
+		BPF_LINE_INFO_ENC(4, 0, NAME_TBD, 5, 6),
+		BTF_END_RAW,
+	},
+	.line_info_rec_size = sizeof(struct bpf_line_info),
+	.nr_jited_ksyms = 1,
+	.dead_code_cnt = 1,
+	.dead_code_mask = 0x01,
+},
+
+{
+	.descr = "line_info (dead end)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0int a=1;\0int b=2;\0return a + b;\0/* dead jmp */\0return a + b;\0/* dead exit */"),
+	.insns = {
+		BPF_MOV64_IMM(BPF_REG_0, 1),
+		BPF_MOV64_IMM(BPF_REG_1, 2),
+		BPF_ALU64_REG(BPF_ADD, BPF_REG_0, BPF_REG_1),
+		BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 10, 1),
+		BPF_EXIT_INSN(),
+		BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.func_info_cnt = 0,
+	.line_info = {
+		BPF_LINE_INFO_ENC(0, 0, NAME_TBD, 1, 12),
+		BPF_LINE_INFO_ENC(1, 0, NAME_TBD, 2, 11),
+		BPF_LINE_INFO_ENC(2, 0, NAME_TBD, 3, 10),
+		BPF_LINE_INFO_ENC(3, 0, NAME_TBD, 4, 9),
+		BPF_LINE_INFO_ENC(4, 0, NAME_TBD, 5, 8),
+		BPF_LINE_INFO_ENC(5, 0, NAME_TBD, 6, 7),
+		BTF_END_RAW,
+	},
+	.line_info_rec_size = sizeof(struct bpf_line_info),
+	.nr_jited_ksyms = 1,
+	.dead_code_cnt = 2,
+	.dead_code_mask = 0x28,
+},
+
+{
+	.descr = "line_info (dead code + subprog + func_info)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
+		BTF_FUNC_PROTO_ENC(1, 1),			/* [2] */
+			BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1),
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [3] */
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [4] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0x\0sub\0main\0int a=1+1;\0/* dead jmp */"
+		    "\0/* dead */\0/* dead */\0/* dead */\0/* dead */"
+		    "\0/* dead */\0/* dead */\0/* dead */\0/* dead */"
+		    "\0return func(a);\0b+=1;\0return b;"),
+	.insns = {
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, 1),
+		BPF_MOV64_REG(BPF_REG_1, BPF_REG_2),
+		BPF_JMP_IMM(BPF_JGE, BPF_REG_2, 0, 8),
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_CALL_REL(1),
+		BPF_EXIT_INSN(),
+		BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+		BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+		BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.func_info_cnt = 2,
+	.func_info_rec_size = 8,
+	.func_info = { {0, 4}, {14, 3} },
+	.line_info = {
+		BPF_LINE_INFO_ENC(0, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(3, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(4, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(5, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(6, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(7, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(8, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(9, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(10, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(11, 0, NAME_TBD, 2, 9),
+		BPF_LINE_INFO_ENC(12, 0, NAME_TBD, 2, 9),
+		BPF_LINE_INFO_ENC(14, 0, NAME_TBD, 3, 8),
+		BPF_LINE_INFO_ENC(16, 0, NAME_TBD, 4, 7),
+		BTF_END_RAW,
+	},
+	.line_info_rec_size = sizeof(struct bpf_line_info),
+	.nr_jited_ksyms = 2,
+	.dead_code_cnt = 9,
+	.dead_code_mask = 0x3fe,
+},
+
+{
+	.descr = "line_info (dead subprog)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
+		BTF_FUNC_PROTO_ENC(1, 1),			/* [2] */
+			BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1),
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [3] */
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [4] */
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [5] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0x\0dead\0main\0func\0int a=1+1;\0/* live call */"
+		    "\0return 0;\0return 0;\0/* dead */\0/* dead */"
+		    "\0/* dead */\0return bla + 1;\0return bla + 1;"
+		    "\0return bla + 1;\0return func(a);\0b+=1;\0return b;"),
+	.insns = {
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_JMP_IMM(BPF_JGE, BPF_REG_2, 0, 1),
+		BPF_CALL_REL(3),
+		BPF_CALL_REL(5),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_CALL_REL(1),
+		BPF_EXIT_INSN(),
+		BPF_MOV64_REG(BPF_REG_0, 2),
+		BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+		BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.func_info_cnt = 3,
+	.func_info_rec_size = 8,
+		.func_info = { {0, 4}, {6, 3}, {9, 5} },
+	.line_info = {
+		BPF_LINE_INFO_ENC(0, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(3, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(4, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(5, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(6, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(7, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(8, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(9, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(10, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(11, 0, NAME_TBD, 2, 9),
+		BTF_END_RAW,
+	},
+	.line_info_rec_size = sizeof(struct bpf_line_info),
+	.nr_jited_ksyms = 2,
+	.dead_code_cnt = 3,
+	.dead_code_mask = 0x70,
+	.dead_func_cnt = 1,
+	.dead_func_mask = 0x2,
+},
+
+{
+	.descr = "line_info (dead last subprog)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
+		BTF_FUNC_PROTO_ENC(1, 1),			/* [2] */
+			BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1),
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [3] */
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [5] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0x\0dead\0main\0int a=1+1;\0/* live call */"
+		    "\0return 0;\0/* dead */\0/* dead */"),
+	.insns = {
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_JMP_IMM(BPF_JGE, BPF_REG_2, 0, 1),
+		BPF_CALL_REL(2),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.func_info_cnt = 2,
+	.func_info_rec_size = 8,
+		.func_info = { {0, 4}, {5, 3} },
+	.line_info = {
+		BPF_LINE_INFO_ENC(0, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(3, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(4, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(5, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(6, 0, NAME_TBD, 1, 10),
+		BTF_END_RAW,
+	},
+	.line_info_rec_size = sizeof(struct bpf_line_info),
+	.nr_jited_ksyms = 1,
+	.dead_code_cnt = 2,
+	.dead_code_mask = 0x18,
+	.dead_func_cnt = 1,
+	.dead_func_mask = 0x2,
+},
+
+{
+	.descr = "line_info (dead subprog + dead start)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
+		BTF_FUNC_PROTO_ENC(1, 1),			/* [2] */
+			BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1),
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [3] */
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [4] */
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [5] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0x\0dead\0main\0func\0int a=1+1;\0/* dead */"
+		    "\0return 0;\0return 0;\0return 0;"
+		    "\0/* dead */\0/* dead */\0/* dead */\0/* dead */"
+		    "\0return b + 1;\0return b + 1;\0return b + 1;"),
+	.insns = {
+		BPF_JMP_IMM(BPF_JA, 0, 0, 0),
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_JMP_IMM(BPF_JGE, BPF_REG_2, 0, 1),
+		BPF_CALL_REL(3),
+		BPF_CALL_REL(5),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_CALL_REL(1),
+		BPF_EXIT_INSN(),
+		BPF_JMP_IMM(BPF_JA, 0, 0, 0),
+		BPF_MOV64_REG(BPF_REG_0, 2),
+		BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+		BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.func_info_cnt = 3,
+	.func_info_rec_size = 8,
+		.func_info = { {0, 4}, {7, 3}, {10, 5} },
+	.line_info = {
+		BPF_LINE_INFO_ENC(0, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(3, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(4, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(5, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(6, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(7, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(8, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(9, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(10, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(11, 0, NAME_TBD, 2, 9),
+		BPF_LINE_INFO_ENC(12, 0, NAME_TBD, 2, 9),
+		BPF_LINE_INFO_ENC(13, 0, NAME_TBD, 2, 9),
+		BTF_END_RAW,
+	},
+	.line_info_rec_size = sizeof(struct bpf_line_info),
+	.nr_jited_ksyms = 2,
+	.dead_code_cnt = 5,
+	.dead_code_mask = 0x1e2,
+	.dead_func_cnt = 1,
+	.dead_func_mask = 0x2,
+},
+
+{
+	.descr = "line_info (dead subprog + dead start w/ move)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
+		BTF_FUNC_PROTO_ENC(1, 1),			/* [2] */
+			BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1),
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [3] */
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [4] */
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [5] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0x\0dead\0main\0func\0int a=1+1;\0/* live call */"
+		    "\0return 0;\0return 0;\0/* dead */\0/* dead */"
+		    "\0/* dead */\0return bla + 1;\0return bla + 1;"
+		    "\0return bla + 1;\0return func(a);\0b+=1;\0return b;"),
+	.insns = {
+		BPF_MOV64_IMM(BPF_REG_2, 1),
+		BPF_JMP_IMM(BPF_JGE, BPF_REG_2, 0, 1),
+		BPF_CALL_REL(3),
+		BPF_CALL_REL(5),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_CALL_REL(1),
+		BPF_EXIT_INSN(),
+		BPF_JMP_IMM(BPF_JA, 0, 0, 0),
+		BPF_MOV64_REG(BPF_REG_0, 2),
+		BPF_ALU64_IMM(BPF_ADD, BPF_REG_0, 1),
+		BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.func_info_cnt = 3,
+	.func_info_rec_size = 8,
+		.func_info = { {0, 4}, {6, 3}, {9, 5} },
+	.line_info = {
+		BPF_LINE_INFO_ENC(0, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(3, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(4, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(5, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(6, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(7, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(8, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(9, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(11, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(12, 0, NAME_TBD, 2, 9),
+		BTF_END_RAW,
+	},
+	.line_info_rec_size = sizeof(struct bpf_line_info),
+	.nr_jited_ksyms = 2,
+	.dead_code_cnt = 3,
+	.dead_code_mask = 0x70,
+	.dead_func_cnt = 1,
+	.dead_func_mask = 0x2,
+},
+
+{
+	.descr = "line_info (dead end + subprog start w/ no linfo)",
+	.raw_types = {
+		BTF_TYPE_INT_ENC(NAME_TBD, BTF_INT_SIGNED, 0, 32, 4),	/* [1] */
+		BTF_FUNC_PROTO_ENC(1, 1),			/* [2] */
+			BTF_FUNC_PROTO_ARG_ENC(NAME_TBD, 1),
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [3] */
+		BTF_FUNC_ENC(NAME_TBD, 2),			/* [4] */
+		BTF_END_RAW,
+	},
+	BTF_STR_SEC("\0int\0x\0main\0func\0/* main linfo */\0/* func linfo */"),
+	.insns = {
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 1, 3),
+		BPF_CALL_REL(3),
+		BPF_MOV64_IMM(BPF_REG_0, 0),
+		BPF_EXIT_INSN(),
+		BPF_EXIT_INSN(),
+		BPF_JMP_IMM(BPF_JA, 0, 0, 0),
+		BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACEPOINT,
+	.func_info_cnt = 2,
+	.func_info_rec_size = 8,
+	.func_info = { {0, 3}, {6, 4}, },
+	.line_info = {
+		BPF_LINE_INFO_ENC(0, 0, NAME_TBD, 1, 10),
+		BPF_LINE_INFO_ENC(6, 0, NAME_TBD, 1, 10),
+		BTF_END_RAW,
+	},
+	.line_info_rec_size = sizeof(struct bpf_line_info),
+	.nr_jited_ksyms = 2,
+},
+
 };
 
 static size_t probe_prog_length(const struct bpf_insn *fp)
@@ -4778,6 +5145,7 @@ static int test_get_finfo(const struct prog_info_raw_test *test,
 	struct bpf_func_info *finfo;
 	__u32 info_len, rec_size, i;
 	void *func_info = NULL;
+	__u32 nr_func_info;
 	int err;
 
 	/* get necessary lens */
@@ -4787,7 +5155,8 @@ static int test_get_finfo(const struct prog_info_raw_test *test,
 		fprintf(stderr, "%s\n", btf_log_buf);
 		return -1;
 	}
-	if (CHECK(info.nr_func_info != test->func_info_cnt,
+	nr_func_info = test->func_info_cnt - test->dead_func_cnt;
+	if (CHECK(info.nr_func_info != nr_func_info,
 		  "incorrect info.nr_func_info (1st) %d",
 		  info.nr_func_info)) {
 		return -1;
@@ -4808,7 +5177,7 @@ static int test_get_finfo(const struct prog_info_raw_test *test,
 
 	/* reset info to only retrieve func_info related data */
 	memset(&info, 0, sizeof(info));
-	info.nr_func_info = test->func_info_cnt;
+	info.nr_func_info = nr_func_info;
 	info.func_info_rec_size = rec_size;
 	info.func_info = ptr_to_u64(func_info);
 	err = bpf_obj_get_info_by_fd(prog_fd, &info, &info_len);
@@ -4817,7 +5186,7 @@ static int test_get_finfo(const struct prog_info_raw_test *test,
 		err = -1;
 		goto done;
 	}
-	if (CHECK(info.nr_func_info != test->func_info_cnt,
+	if (CHECK(info.nr_func_info != nr_func_info,
 		  "incorrect info.nr_func_info (2nd) %d",
 		  info.nr_func_info)) {
 		err = -1;
@@ -4831,7 +5200,9 @@ static int test_get_finfo(const struct prog_info_raw_test *test,
 	}
 
 	finfo = func_info;
-	for (i = 0; i < test->func_info_cnt; i++) {
+	for (i = 0; i < nr_func_info; i++) {
+		if (test->dead_func_mask & (1 << i))
+			continue;
 		if (CHECK(finfo->type_id != test->func_info[i][1],
 			  "incorrect func_type %u expected %u",
 			  finfo->type_id, test->func_info[i][1])) {
@@ -4860,6 +5231,7 @@ static int test_get_linfo(const struct prog_info_raw_test *test,
 	struct bpf_prog_info info = {};
 	__u32 *jited_func_lens = NULL;
 	__u64 cur_func_ksyms;
+	__u32 dead_insns;
 	int err;
 
 	jited_cnt = cnt;
@@ -4868,7 +5240,7 @@ static int test_get_linfo(const struct prog_info_raw_test *test,
 	if (test->nr_jited_ksyms)
 		nr_jited_ksyms = test->nr_jited_ksyms;
 	else
-		nr_jited_ksyms = test->func_info_cnt;
+		nr_jited_ksyms = test->func_info_cnt - test->dead_func_cnt;
 	nr_jited_func_lens = nr_jited_ksyms;
 
 	info_len = sizeof(struct bpf_prog_info);
@@ -4970,12 +5342,20 @@ static int test_get_linfo(const struct prog_info_raw_test *test,
 		goto done;
 	}
 
+	dead_insns = 0;
+	while (test->dead_code_mask & (1 << dead_insns))
+		dead_insns++;
+
 	CHECK(linfo[0].insn_off, "linfo[0].insn_off:%u",
 	      linfo[0].insn_off);
 	for (i = 1; i < cnt; i++) {
 		const struct bpf_line_info *expected_linfo;
 
-		expected_linfo = patched_linfo + (i * test->line_info_rec_size);
+		while (test->dead_code_mask & (1 << (i + dead_insns)))
+			dead_insns++;
+
+		expected_linfo = patched_linfo +
+			((i + dead_insns) * test->line_info_rec_size);
 		if (CHECK(linfo[i].insn_off <= linfo[i - 1].insn_off,
 			  "linfo[%u].insn_off:%u <= linfo[%u].insn_off:%u",
 			  i, linfo[i].insn_off,
@@ -5133,7 +5513,9 @@ static int do_test_info_raw(unsigned int test_num)
 	if (err)
 		goto done;
 
-	err = test_get_linfo(test, patched_linfo, attr.line_info_cnt, prog_fd);
+	err = test_get_linfo(test, patched_linfo,
+			     attr.line_info_cnt - test->dead_code_cnt,
+			     prog_fd);
 	if (err)
 		goto done;
 
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index 2fd90d456892..4f67afeec8d9 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -15599,6 +15599,166 @@ static struct bpf_test tests[] = {
 		.result_unpriv = ACCEPT,
 		.result = ACCEPT,
 	},
+	{
+		"dead code: start",
+		.insns = {
+			BPF_JMP_IMM(BPF_JA, 0, 0, 2),
+			BPF_LDX_MEM(BPF_B, BPF_REG_8, BPF_REG_9, 0),
+			BPF_JMP_IMM(BPF_JA, 0, 0, 2),
+			BPF_MOV64_IMM(BPF_REG_0, 7),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 10, -4),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.retval = 7,
+	},
+	{
+		"dead code: mid 1",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 7),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 0, 1),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 10, 0),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.retval = 7,
+	},
+	{
+		"dead code: mid 2",
+		.insns = {
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 0, 0,
+				     BPF_FUNC_get_prandom_u32),
+			BPF_JMP_IMM(BPF_JSET, BPF_REG_0, 1, 4),
+			BPF_JMP_IMM(BPF_JSET, BPF_REG_0, 1, 1),
+			BPF_JMP_IMM(BPF_JA, 0, 0, 2),
+			BPF_MOV64_IMM(BPF_REG_0, 7),
+			BPF_EXIT_INSN(),
+			BPF_MOV64_IMM(BPF_REG_0, 1),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.retval = 1,
+	},
+	{
+		"dead code: end 1",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 7),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 10, 1),
+			BPF_EXIT_INSN(),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.retval = 7,
+	},
+	{
+		"dead code: end 2",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 7),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 10, 1),
+			BPF_EXIT_INSN(),
+			BPF_MOV64_IMM(BPF_REG_0, 12),
+			BPF_EXIT_INSN(),
+		},
+		.result = ACCEPT,
+		.retval = 7,
+	},
+	{
+		"dead code: end 3",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 7),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 8, 1),
+			BPF_EXIT_INSN(),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 10, 1),
+			BPF_JMP_IMM(BPF_JA, 0, 0, 1),
+			BPF_MOV64_IMM(BPF_REG_0, 12),
+			BPF_JMP_IMM(BPF_JA, 0, 0, -5),
+		},
+		.result = ACCEPT,
+		.retval = 7,
+	},
+	{
+		"dead code: tail of main + func",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 7),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 8, 1),
+			BPF_EXIT_INSN(),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
+			BPF_EXIT_INSN(),
+			BPF_MOV64_IMM(BPF_REG_0, 12),
+			BPF_EXIT_INSN(),
+		},
+		.errstr_unpriv = "function calls to other bpf functions are allowed for root only",
+		.result_unpriv = REJECT,
+		.result = ACCEPT,
+		.retval = 7,
+	},
+	{
+		"dead code: tail of main + two functions",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_0, 7),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_0, 8, 1),
+			BPF_EXIT_INSN(),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
+			BPF_EXIT_INSN(),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
+			BPF_EXIT_INSN(),
+			BPF_MOV64_IMM(BPF_REG_0, 12),
+			BPF_EXIT_INSN(),
+		},
+		.errstr_unpriv = "function calls to other bpf functions are allowed for root only",
+		.result_unpriv = REJECT,
+		.result = ACCEPT,
+		.retval = 7,
+	},
+	{
+		"dead code: function in the middle and mid of another func",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_1, 7),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 3),
+			BPF_EXIT_INSN(),
+			BPF_MOV64_IMM(BPF_REG_0, 12),
+			BPF_EXIT_INSN(),
+			BPF_MOV64_IMM(BPF_REG_0, 7),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_1, 7, 1),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, -5),
+			BPF_EXIT_INSN(),
+		},
+		.errstr_unpriv = "function calls to other bpf functions are allowed for root only",
+		.result_unpriv = REJECT,
+		.result = ACCEPT,
+		.retval = 7,
+	},
+	{
+		"dead code: middle of main before call",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_1, 2),
+			BPF_JMP_IMM(BPF_JGE, BPF_REG_1, 2, 1),
+			BPF_MOV64_IMM(BPF_REG_1, 5),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
+			BPF_EXIT_INSN(),
+			BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+			BPF_EXIT_INSN(),
+		},
+		.errstr_unpriv = "function calls to other bpf functions are allowed for root only",
+		.result_unpriv = REJECT,
+		.result = ACCEPT,
+		.retval = 2,
+	},
+	{
+		"dead code: start of a function",
+		.insns = {
+			BPF_MOV64_IMM(BPF_REG_1, 2),
+			BPF_RAW_INSN(BPF_JMP | BPF_CALL, 0, 1, 0, 1),
+			BPF_EXIT_INSN(),
+			BPF_JMP_IMM(BPF_JA, 0, 0, 0),
+			BPF_MOV64_REG(BPF_REG_0, BPF_REG_1),
+			BPF_EXIT_INSN(),
+		},
+		.errstr_unpriv = "function calls to other bpf functions are allowed for root only",
+		.result_unpriv = REJECT,
+		.result = ACCEPT,
+		.retval = 2,
+	},
 };
 
 static int probe_filter_length(const struct bpf_insn *fp)