On Thu, Aug 20, 2026 at 8:51 PM Fuyu Zhao <[email protected]> wrote: > > > > On 8/21/2026 8:10 AM, Eduard Zingerman wrote: > > On Wed, 2026-08-19 at 17:04 +0800, Fuyu Zhao wrote: > > > > ... > > > >> +++ b/tools/testing/selftests/bpf/prog_tests/kmod_btfs.c > >> @@ -0,0 +1,196 @@ > >> +// SPDX-License-Identifier: GPL-2.0 > >> +#include <test_progs.h> > >> +#include "kmod_btfs.skel.h" > >> + > >> +static bool btf_skipped; > >> +static bool dup_ignored; > >> + > >> +static const char btf_skip_fmt[] = > >> + "libbpf: skipping module BTF '%s', not in kmod_btf_names\n"; > >> +static const char dup_ignore_fmt[] = > >> + "libbpf: duplicate kmod BTF name '%s' ignored\n"; > >> + > >> +static int libbpf_print_cb(enum libbpf_print_level level, const char *fmt, > >> + va_list args) > >> +{ > >> + if (!strcmp(fmt, btf_skip_fmt)) { > >> + if (!strcmp(va_arg(args, char *), "bpf_test_no_cfi")) > >> + btf_skipped = true; > >> + } else if (!strcmp(fmt, dup_ignore_fmt)) { > >> + if (!strcmp(va_arg(args, char *), "bpf_testmod")) > >> + dup_ignored = true; > >> + } > >> + > >> + return 0; > >> +} > > > > Idk what Andrii would say about this, but I'd rather add an internal > > function akin to: > > > > size_t bpf_object_btf_module_cnt(const struct bpf_object *obj); > > > > in libbpf.c and expose it via libbpf_internal.h (*not* via API), > > instead of intercepting log messages. > > > > ... > > I think your suggestion is better. It also addresses the issue raised by > the bot about potentially hiding other libbpf logs. I'll wait for Andrii's > feedback on this. >
I would do neither and just not validate explicitly that we skipped (or not) some module. Instead, I'd see if it's simple and maintainable to do a functional test: try to attach to a func or have relocation fail against a type of a test module you explicitly do not allow to load. If that succeeds, bad. Also have positive and negative tests to show this custom kernel module list makes a difference as promised. And try to keep the boilerplate to a minimum with all this, don't go overboard. > Thanks, > Fuyu >
