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Add a test that loads an XDP program with a global subprogram using a BPF token from a user namespace, then verifies that both the main program and the subprogram appear in /proc/kallsyms. This exercises the bpf_prog_kallsyms_add() path for subprograms and would have caught the missing aux->token copy in bpf_jit_subprogs(). load_kallsyms_local() filters out kallsyms with zero addresses. For a process with limited capabilities to read kallsym addresses the following sysctl variables have to be set to zero: - /proc/sys/kernel/perf_event_paranoid - /proc/sys/kernel/kptr_restrict Set these variables using sysctl_set() utility function extracted from unpriv_bpf_disabled.c to a separate c/header. Since the test modifies global system state, mark it as serial. Signed-off-by: Eduard Zingerman <eddyz87@gmail.com> Link: https://lore.kernel.org/r/20260415-subprog-token-fix-v4-2-9bd000e8b068@gmail.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
20 lines
321 B
C
20 lines
321 B
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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char _license[] SEC("license") = "GPL";
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__weak
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int token_ksym_subprog(void)
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{
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return 0;
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}
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SEC("xdp")
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int xdp_main(struct xdp_md *xdp)
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{
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return token_ksym_subprog();
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}
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