On Thu, May 5, 2022 at 6:17 AM Larysa Zaremba <larysa.zaremba@xxxxxxxxx> wrote: > > Currently, dumping almost all BTFs specified by id requires > using the -B option to pass the base BTF. For kernel module > BTFs the vmlinux BTF sysfs path should work. > > This patch simplifies dumping by ID usage by attempting to > use vmlinux BTF from sysfs, if the first try of loading BTF by ID > fails with certain conditions and the ID corresponds to a kernel > module BTF. It feels sloppy to first try without base BTF and then fallback to base BTF. When specified ID of BTF object, let's just get its struct bpf_btf_info with bpf_obj_get_info_by_fd() and then check that kernel_btf is set and name isn't "vmlinux". This will mean it's kernel module, so load base BTF from /sys/kernel/btf/vmlinux. If that fails, there is no way that kernel module BTF will be successfully loaded, so there is no point in trying. > > Signed-off-by: Larysa Zaremba <larysa.zaremba@xxxxxxxxx> > Reviewed-by: Alexander Lobakin <alexandr.lobakin@xxxxxxxxx> > --- > tools/bpf/bpftool/btf.c | 67 +++++++++++++++++++++++++++++++++++------ > 1 file changed, 58 insertions(+), 9 deletions(-) > [...]
