1 files changed, 108 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/kmem_cache_iter.c b/tools/testing/selftests/bpf/progs/kmem_cache_iter.c
new file mode 100644
index 000000000000..b9c8f9457492
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kmem_cache_iter.c
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2024 Google */
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include "bpf_experimental.h"
+
+char _license[] SEC("license") = "GPL";
+
+#define SLAB_NAME_MAX  32
+
+struct kmem_cache_result {
+	char name[SLAB_NAME_MAX];
+	long obj_size;
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_HASH);
+	__uint(key_size, sizeof(void *));
+	__uint(value_size, SLAB_NAME_MAX);
+	__uint(max_entries, 1);
+} slab_hash SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_ARRAY);
+	__uint(key_size, sizeof(int));
+	__uint(value_size, sizeof(struct kmem_cache_result));
+	__uint(max_entries, 1024);
+} slab_result SEC(".maps");
+
+extern struct kmem_cache *bpf_get_kmem_cache(u64 addr) __ksym;
+
+/* Result, will be checked by userspace */
+int task_struct_found;
+int kmem_cache_seen;
+int open_coded_seen;
+
+SEC("iter/kmem_cache")
+int slab_info_collector(struct bpf_iter__kmem_cache *ctx)
+{
+	struct seq_file *seq = ctx->meta->seq;
+	struct kmem_cache *s = ctx->s;
+	struct kmem_cache_result *r;
+	int idx;
+
+	if (s) {
+		/* To make sure if the slab_iter implements the seq interface
+		 * properly and it's also useful for debugging.
+		 */
+		BPF_SEQ_PRINTF(seq, "%s: %u\n", s->name, s->size);
+
+		idx = kmem_cache_seen;
+		r = bpf_map_lookup_elem(&slab_result, &idx);
+		if (r == NULL)
+			return 0;
+
+		kmem_cache_seen++;
+
+		/* Save name and size to match /proc/slabinfo */
+		bpf_probe_read_kernel_str(r->name, sizeof(r->name), s->name);
+		r->obj_size = s->size;
+
+		if (!bpf_strncmp(r->name, 11, "task_struct"))
+			bpf_map_update_elem(&slab_hash, &s, r->name, BPF_NOEXIST);
+	}
+
+	return 0;
+}
+
+SEC("raw_tp/bpf_test_finish")
+int BPF_PROG(check_task_struct)
+{
+	u64 curr = bpf_get_current_task();
+	struct kmem_cache *s;
+	char *name;
+
+	s = bpf_get_kmem_cache(curr);
+	if (s == NULL) {
+		task_struct_found = -1;
+		return 0;
+	}
+	name = bpf_map_lookup_elem(&slab_hash, &s);
+	if (name && !bpf_strncmp(name, 11, "task_struct"))
+		task_struct_found = 1;
+	else
+		task_struct_found = -2;
+	return 0;
+}
+
+SEC("syscall")
+int open_coded_iter(const void *ctx)
+{
+	struct kmem_cache *s;
+
+	bpf_for_each(kmem_cache, s) {
+		struct kmem_cache_result *r;
+
+		r = bpf_map_lookup_elem(&slab_result, &open_coded_seen);
+		if (!r)
+			break;
+
+		if (r->obj_size != s->size)
+			break;
+
+		open_coded_seen++;
+	}
+	return 0;
+}