bpftool's -d option is documented to enable bpf_trace_printk() messages
from the generated syscall loader when used with -L as specified in
commit d510296d331a ("bpftool: Use syscall/loader program in "prog load"
and "gen skeleton" command.")
However commit b59e4ce8bcaa ("bpftool: Switch bpf_object__load_xattr()
to bpf_object__load()") changed bpftool to use bpf_object__load() which
call the internal bpf_object_load with extra_log_level to 0 instead of
bpf_object__load_xattr with the user request log_level.
All the plumbing was still there to generate the bpf_trace_printk()
instructions from the generator but was now unreachable because
bpf_gen__init() was called with extra_log_level to 0, leaving
gen->log_level at 0.
This uses the obj->log_level field introduced in commit e0e3ea888c69
("libbpf: Allow passing user log setting through bpf_object_open_opts")
set from reading verifier_logs in do_skeleton(). This preserves both
object-level and explicit load-time logging settings.
Fixes: b59e4ce8bcaa ("bpftool: Switch bpf_object__load_xattr() to bpf_object__load()")
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Mahe Tardy <mahe.tardy@gmail.com>
Link: https://lore.kernel.org/r/20260907170536.9996-1-mahe.tardy@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
