tools/testing/selftests/bpf/progs/bpf_ma_ttrace.c

// SPDX-License-Identifier: GPL-2.0
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_core_read.h>
#include "bpf_kfuncs.h"

struct {
	__uint(type, BPF_MAP_TYPE_HASH);
	__uint(map_flags, BPF_F_NO_PREALLOC);
	__uint(max_entries, 4096);
	__type(key, int);
	__type(value, long);
} htab SEC(".maps");

extern const void __per_cpu_offset __ksym;

int nr_cpus;
int nr_caches;
int in_progress;
int not_freed;

/* Look at bpf_mem_cache of every cpu that htab allocates its elements from */
SEC("syscall")
int check_ttrace(void *ctx)
{
	struct bpf_htab *h = bpf_core_cast(&htab, struct bpf_htab);
	unsigned long cache = (unsigned long)BPF_CORE_READ(h, ma.cache);
	const unsigned long *offsets = &__per_cpu_offset;
	struct bpf_mem_cache *c;
	unsigned long off;
	int cpu;

	nr_caches = 0;
	in_progress = 0;
	not_freed = 0;
	bpf_for(cpu, 0, nr_cpus) {
		if (bpf_probe_read_kernel(&off, sizeof(off), offsets + cpu))
			return -1;
		c = bpf_core_cast((void *)(cache + off), struct bpf_mem_cache);
		if (c->unit_size)
			nr_caches++;
		if (c->call_rcu_ttrace_in_progress.counter)
			in_progress++;
		if (c->free_by_rcu_ttrace.first || c->waiting_for_gp_ttrace.first)
			not_freed++;
	}
	return 0;
}

char _license[] SEC("license") = "GPL";