On Sun, Jul 31, 2022 at 05:26:49PM -0600, James Hilliard wrote: > The GNU assembler generates an empty .bss section. This is a well > established behavior in GAS that happens in all supported targets. > > The LLVM assembler doesn't generate an empty .bss section. > > bpftool chokes on the empty .bss section. > > Additionally in bpf_object__elf_collect the sec_desc->data is not > initialized when a section is not recognized. In this case, this > happens with .comment. > > So we must check that sec_desc->data is initialized before checking > if the size is 0. oops David send same change but I asked him to move the check to bpf_object__elf_collect [1] .. but with your explanation this fix actualy looks fine to me jirka [1] https://lore.kernel.org/bpf/YuKaFiZ+ksB5f0Ye@krava/ > > Signed-off-by: James Hilliard <james.hilliard1@xxxxxxxxx> > Cc: Jose E. Marchesi <jose.marchesi@xxxxxxxxxx> > --- > tools/lib/bpf/libbpf.c | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c > index 50d41815f431..77e3797cf75a 100644 > --- a/tools/lib/bpf/libbpf.c > +++ b/tools/lib/bpf/libbpf.c > @@ -1642,6 +1642,10 @@ static int bpf_object__init_global_data_maps(struct bpf_object *obj) > for (sec_idx = 1; sec_idx < obj->efile.sec_cnt; sec_idx++) { > sec_desc = &obj->efile.secs[sec_idx]; > > + /* Skip recognized sections with size 0. */ > + if (sec_desc->data && sec_desc->data->d_size == 0) > + continue; > + > switch (sec_desc->sec_type) { > case SEC_DATA: > sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); > -- > 2.34.1 >
