// SPDX-License-Identifier: GPL-2.0 /* Copyright (c) 2026 Varun R Mallya */ #include <vmlinux.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_tracing.h> #include "../test_kmods/bpf_testmod.h" #include "bpf_misc.h" char _license[] SEC("license") = "GPL"; struct { __uint(type, BPF_MAP_TYPE_PROG_ARRAY); __uint(max_entries, 1); __uint(key_size, sizeof(__u32)); __uint(value_size, sizeof(__u32)); } prog_array SEC(".maps"); SEC("struct_ops/test_refcounted_multi") __failure __msg("program with __ref argument cannot tail call") int test_refcounted_multi(unsigned long long *ctx) { /* ctx[2] is used because the refcounted variable is the third argument */ struct task_struct *refcounted_task = (struct task_struct *)ctx[2]; bpf_task_release(refcounted_task); bpf_tail_call(ctx, &prog_array, 0); return 0; } SEC(".struct_ops.link") struct bpf_testmod_ops testmod_ref_acquire = { .test_refcounted_multi = (void *)test_refcounted_multi, };