en Copyright 2015 Java http://kernelsources.org:8080/source/history/linux/tools/testing/selftests/bpf/sysctl_helpers.c#969fb456ffb43d87894a295dbe6a0a722691552a selftests/bpf: verify kallsyms entries for token-loaded subprogramsAdd a test that loads an XDP program with a global subprogram using aBPF token from a user namespace, then verifies that both the mainprogram and the subprogram appear in /proc/kallsyms.This exercises the bpf_prog_kallsyms_add() path for subprograms andwould 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 thefollowing sysctl variables have to be set to zero:- /proc/sys/kernel/perf_event_paranoid- /proc/sys/kernel/kptr_restrictSet these variables using sysctl_set() utility function extracted fromunpriv_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.comSigned-off-by: Alexei Starovoitov <ast@kernel.org> List of files: /linux/tools/testing/selftests/bpf/sysctl_helpers.c Wed, 15 Apr 2026 22:03:56 +0200 Eduard Zingerman <eddyz87@gmail.com>