selftests/bpf: Use bpf_program__clone() in veristat

Replace veristat's per-program object re-opening with
bpf_program__clone().

Previously, veristat opened a separate bpf_object for every program in a
multi-program object file, iterated all programs to enable only the
target one, and then loaded the entire object.

Use bpf_object__prepare() once, then call bpf_program__clone() for each
program individually. This lets veristat load programs one at a time
from a single prepared object.

The caller now owns the returned fd and closes it after collecting stats.
Remove the special single-program fast path and the per-file early exit
in handle_verif_mode() so all files are always processed.

Split fixup_obj() into fixup_obj_maps() for object-wide map fixups that
must run before bpf_object__prepare(), and fixup_obj() for per-program
fixups (struct_ops masking, freplace type guessing) that run before each
bpf_program__clone() call.

Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20260317-veristat_prepare-v4-2-74193d4cc9d9@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 42 insertions, 60 deletions

diff --git a/tools/testing/selftests/bpf/veristat.c b/tools/testing/selftests/bpf/veristat.c
index 75f85e0362f5..9652649171ce 100644
--- a/tools/testing/selftests/bpf/veristat.c
+++ b/tools/testing/selftests/bpf/veristat.c
@@ -1236,7 +1236,7 @@ static void mask_unrelated_struct_ops_progs(struct bpf_object *obj,
 	}
 }
 
-static void fixup_obj(struct bpf_object *obj, struct bpf_program *prog, const char *filename)
+static void fixup_obj_maps(struct bpf_object *obj)
 {
 	struct bpf_map *map;
 
@@ -1251,15 +1251,23 @@ static void fixup_obj(struct bpf_object *obj, struct bpf_program *prog, const ch
 		case BPF_MAP_TYPE_INODE_STORAGE:
 		case BPF_MAP_TYPE_CGROUP_STORAGE:
 		case BPF_MAP_TYPE_CGRP_STORAGE:
-			break;
 		case BPF_MAP_TYPE_STRUCT_OPS:
-			mask_unrelated_struct_ops_progs(obj, map, prog);
 			break;
 		default:
 			if (bpf_map__max_entries(map) == 0)
 				bpf_map__set_max_entries(map, 1);
 		}
 	}
+}
+
+static void fixup_obj(struct bpf_object *obj, struct bpf_program *prog, const char *filename)
+{
+	struct bpf_map *map;
+
+	bpf_object__for_each_map(map, obj) {
+		if (bpf_map__type(map) == BPF_MAP_TYPE_STRUCT_OPS)
+			mask_unrelated_struct_ops_progs(obj, map, prog);
+	}
 
 	/* SEC(freplace) programs can't be loaded with veristat as is,
 	 * but we can try guessing their target program's expected type by
@@ -1608,6 +1616,7 @@ static int process_prog(const char *filename, struct bpf_object *obj, struct bpf
 	const char *base_filename = basename(strdupa(filename));
 	const char *prog_name = bpf_program__name(prog);
 	long mem_peak_a, mem_peak_b, mem_peak = -1;
+	LIBBPF_OPTS(bpf_prog_load_opts, opts);
 	char *buf;
 	int buf_sz, log_level;
 	struct verif_stats *stats;
@@ -1647,9 +1656,6 @@ static int process_prog(const char *filename, struct bpf_object *obj, struct bpf
 	}
 	verif_log_buf[0] = '\0';
 
-	bpf_program__set_log_buf(prog, buf, buf_sz);
-	bpf_program__set_log_level(prog, log_level);
-
 	/* increase chances of successful BPF object loading */
 	fixup_obj(obj, prog, base_filename);
 
@@ -1658,15 +1664,21 @@ static int process_prog(const char *filename, struct bpf_object *obj, struct bpf
 	if (env.force_reg_invariants)
 		bpf_program__set_flags(prog, bpf_program__flags(prog) | BPF_F_TEST_REG_INVARIANTS);
 
-	err = bpf_object__prepare(obj);
-	if (!err) {
-		cgroup_err = reset_stat_cgroup();
-		mem_peak_a = cgroup_memory_peak();
-		err = bpf_object__load(obj);
-		mem_peak_b = cgroup_memory_peak();
-		if (!cgroup_err && mem_peak_a >= 0 && mem_peak_b >= 0)
-			mem_peak = mem_peak_b - mem_peak_a;
+	opts.log_buf = buf;
+	opts.log_size = buf_sz;
+	opts.log_level = log_level;
+
+	cgroup_err = reset_stat_cgroup();
+	mem_peak_a = cgroup_memory_peak();
+	fd = bpf_program__clone(prog, &opts);
+	if (fd < 0) {
+		err = fd;
+		fprintf(stderr, "Failed to load program %s %d\n", prog_name, err);
 	}
+	mem_peak_b = cgroup_memory_peak();
+	if (!cgroup_err && mem_peak_a >= 0 && mem_peak_b >= 0)
+		mem_peak = mem_peak_b - mem_peak_a;
+
 	env.progs_processed++;
 
 	stats->file_name = strdup(base_filename);
@@ -1678,7 +1690,6 @@ static int process_prog(const char *filename, struct bpf_object *obj, struct bpf
 	stats->stats[MEMORY_PEAK] = mem_peak < 0 ? -1 : mem_peak / (1024 * 1024);
 
 	memset(&info, 0, info_len);
-	fd = bpf_program__fd(prog);
 	if (fd > 0 && bpf_prog_get_info_by_fd(fd, &info, &info_len) == 0) {
 		stats->stats[JITED_SIZE] = info.jited_prog_len;
 		if (env.dump_mode & DUMP_JITED)
@@ -1699,7 +1710,8 @@ static int process_prog(const char *filename, struct bpf_object *obj, struct bpf
 
 	if (verif_log_buf != buf)
 		free(buf);
-
+	if (fd > 0)
+		close(fd);
 	return 0;
 }
 
@@ -2182,8 +2194,8 @@ static int set_global_vars(struct bpf_object *obj, struct var_preset *presets, i
 static int process_obj(const char *filename)
 {
 	const char *base_filename = basename(strdupa(filename));
-	struct bpf_object *obj = NULL, *tobj;
-	struct bpf_program *prog, *tprog, *lprog;
+	struct bpf_object *obj = NULL;
+	struct bpf_program *prog;
 	libbpf_print_fn_t old_libbpf_print_fn;
 	LIBBPF_OPTS(bpf_object_open_opts, opts);
 	int err = 0, prog_cnt = 0;
@@ -2222,51 +2234,24 @@ static int process_obj(const char *filename)
 	env.files_processed++;
 
 	bpf_object__for_each_program(prog, obj) {
+		bpf_program__set_autoload(prog, true);
 		prog_cnt++;
 	}
 
-	if (prog_cnt == 1) {
-		prog = bpf_object__next_program(obj, NULL);
-		bpf_program__set_autoload(prog, true);
-		err = set_global_vars(obj, env.presets, env.npresets);
-		if (err) {
-			fprintf(stderr, "Failed to set global variables %d\n", err);
-			goto cleanup;
-		}
-		process_prog(filename, obj, prog);
+	fixup_obj_maps(obj);
+
+	err = set_global_vars(obj, env.presets, env.npresets);
+	if (err) {
+		fprintf(stderr, "Failed to set global variables %d\n", err);
 		goto cleanup;
 	}
 
-	bpf_object__for_each_program(prog, obj) {
-		const char *prog_name = bpf_program__name(prog);
-
-		tobj = bpf_object__open_file(filename, &opts);
-		if (!tobj) {
-			err = -errno;
-			fprintf(stderr, "Failed to open '%s': %d\n", filename, err);
-			goto cleanup;
-		}
-
-		err = set_global_vars(tobj, env.presets, env.npresets);
-		if (err) {
-			fprintf(stderr, "Failed to set global variables %d\n", err);
-			goto cleanup;
-		}
-
-		lprog = NULL;
-		bpf_object__for_each_program(tprog, tobj) {
-			const char *tprog_name = bpf_program__name(tprog);
-
-			if (strcmp(prog_name, tprog_name) == 0) {
-				bpf_program__set_autoload(tprog, true);
-				lprog = tprog;
-			} else {
-				bpf_program__set_autoload(tprog, false);
-			}
-		}
+	err = bpf_object__prepare(obj);
+	if (err) /* run process_prog() anyway to output per program failures */
+		fprintf(stderr, "Failed to prepare BPF object for loading %d\n", err);
 
-		process_prog(filename, tobj, lprog);
-		bpf_object__close(tobj);
+	bpf_object__for_each_program(prog, obj) {
+		process_prog(filename, obj, prog);
 	}
 
 cleanup:
@@ -3264,17 +3249,14 @@ static int handle_verif_mode(void)
 	create_stat_cgroup();
 	for (i = 0; i < env.filename_cnt; i++) {
 		err = process_obj(env.filenames[i]);
-		if (err) {
+		if (err)
 			fprintf(stderr, "Failed to process '%s': %d\n", env.filenames[i], err);
-			goto out;
-		}
 	}
 
 	qsort(env.prog_stats, env.prog_stat_cnt, sizeof(*env.prog_stats), cmp_prog_stats);
 
 	output_prog_stats();
 
-out:
 	destroy_stat_cgroup();
 	return err;
 }