Tests for multiple analyses performed by the verifier need the
verifier log to contain analysis results alongside the program
disassembly. This patch moves the log-level-2 program dump from
bpf_compute_live_registers() to a standalone function called from
bpf_check(), in order to provide a common logging function for such
analyses (and thus avoid printing program disassembly multiple times).

Rename the dump header from "Live regs before insn:" to
"Program dump (scc? insn#: live_regs_before):" and print available
source-line information before the corresponding instructions.

Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
---
 kernel/bpf/liveness.c                              | 28 +---------------
 kernel/bpf/verifier.c                              | 37 ++++++++++++++++++++++
 .../selftests/bpf/progs/verifier_live_stack.c      |  2 +-
 3 files changed, 39 insertions(+), 28 deletions(-)

diff --git a/kernel/bpf/liveness.c b/kernel/bpf/liveness.c
index ce74e3f16eef..d5cee598f4c5 100644
--- a/kernel/bpf/liveness.c
+++ b/kernel/bpf/liveness.c
@@ -2624,8 +2624,7 @@ int bpf_compute_live_registers(struct bpf_verifier_env *env)
 	struct bpf_insn *insns = env->prog->insnsi;
 	struct insn_live_regs *state;
 	int insn_cnt = env->prog->len;
-	u64 pos, insn_pos;
-	int err = 0, i, j, subprog, start, end;
+	int err = 0, i, subprog, start, end;
 	bool changed, ret_reg_pair;
 
 	/* Use the following algorithm:
@@ -2704,31 +2703,6 @@ int bpf_compute_live_registers(struct bpf_verifier_env *env)
 		insn_aux[i].zext_dst = def32 >= 0 && (mask_hi(out) & BIT(def32));
 	}
 
-	if (env->log.level & BPF_LOG_LEVEL2) {
-		verbose(env, "Live regs before insn:\n");
-		for (i = 0; i < insn_cnt; ++i) {
-			if (env->insn_aux_data[i].scc)
-				verbose(env, "%3d ", env->insn_aux_data[i].scc);
-			else
-				verbose(env, "    ");
-			verbose(env, "%3d: ", i);
-			for (j = BPF_REG_0; j < BPF_REG_10; ++j)
-				if (insn_aux[i].live_regs_before & BIT(j))
-					verbose(env, "%d", j);
-				else
-					verbose(env, ".");
-			verbose(env, " ");
-			pos = env->log.end_pos;
-			bpf_verbose_insn(env, &insns[i]);
-			insn_pos = env->log.end_pos;
-			if (insn_aux[i].zext_dst)
-				verbose(env, "%*c; zext", bpf_vlog_alignment(insn_pos - pos), ' ');
-			verbose(env, "\n");
-			if (bpf_is_ldimm64(&insns[i]))
-				i++;
-		}
-	}
-
 out:
 	kvfree(state);
 	return err;
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 3298e2192239..c5a3b0f75742 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -22736,6 +22736,40 @@ static bool bpf_prog_reenters_datapath(const struct bpf_prog *prog)
 	return false;
 }
 
+/* Various log level 2 information about the program */
+static void log_program(struct bpf_verifier_env *env)
+{
+	struct bpf_insn_aux_data *insn_aux = env->insn_aux_data;
+	struct bpf_insn *insns = env->prog->insnsi;
+	u32 insn_cnt = env->prog->len;
+	u64 pos, insn_pos;
+	u32 i, j;
+
+	verbose(env, "Program dump (scc? insn#: live_regs_before):\n");
+	for (i = 0; i < insn_cnt; ++i) {
+		verbose_linfo(env, i, "    ; ");
+		if (env->insn_aux_data[i].scc)
+			verbose(env, "%3d ", env->insn_aux_data[i].scc);
+		else
+			verbose(env, "    ");
+		verbose(env, "%3d: ", i);
+		for (j = BPF_REG_0; j < BPF_REG_10; ++j)
+			if (insn_aux[i].live_regs_before & BIT(j))
+				verbose(env, "%d", j);
+			else
+				verbose(env, ".");
+		verbose(env, " ");
+		pos = env->log.end_pos;
+		bpf_verbose_insn(env, &insns[i]);
+		insn_pos = env->log.end_pos;
+		if (insn_aux[i].zext_dst)
+			verbose(env, "%*c; zext", bpf_vlog_alignment(insn_pos - pos), ' ');
+		verbose(env, "\n");
+		if (bpf_is_ldimm64(&insns[i]))
+			i++;
+	}
+}
+
 int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr,
 	      struct bpf_log_attr *attr_log)
 {
@@ -22944,6 +22978,9 @@ int bpf_check(struct bpf_prog **prog, union bpf_attr *attr, bpfptr_t uattr,
 	if (ret < 0)
 		goto skip_full_check;
 
+	if (env->log.level & BPF_LOG_LEVEL2)
+		log_program(env);
+
 	ret = mark_fastcall_patterns(env);
 	if (ret < 0)
 		goto skip_full_check;
diff --git a/tools/testing/selftests/bpf/progs/verifier_live_stack.c b/tools/testing/selftests/bpf/progs/verifier_live_stack.c
index 3ba21430bb75..0e6f25a09b5d 100644
--- a/tools/testing/selftests/bpf/progs/verifier_live_stack.c
+++ b/tools/testing/selftests/bpf/progs/verifier_live_stack.c
@@ -66,7 +66,7 @@ __msg("stack use/def subprog#0 must_write_not_same_slot (d0,cs0):")
  * but the write conservatively marks the whole frame as may_def.
  */
 __msg("6: (7b) *(u64 *)(r2 +0) = r0         ; may_def: fp0-8..-{{(512|2048)}}")
-__msg("Live regs before insn:")
+__msg("Program dump")
 __naked void must_write_not_same_slot(void)
 {
 	asm volatile (

-- 
2.53.0