From: Ian Rogers <irogers@google.com> mainline inclusion from mainline-5.13-rc4 commit 9683e5775c75097c46bd24e65411b16ac6c6cbb3 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ------------------------------------------------- Avoids a segv if btf isn't present. Seen on the call path __bpf_object__open calling bpf_object__collect_externs. Fixes: 5bd022ec01f0 (libbpf: Support extern kernel function) Suggested-by: Stanislav Fomichev <sdf@google.com> Suggested-by: Petar Penkov <ppenkov@google.com> Signed-off-by: Ian Rogers <irogers@google.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20210504234910.976501-1-irogers@google.com (cherry picked from commit 9683e5775c75097c46bd24e65411b16ac6c6cbb3) Signed-off-by: Wang Yufen <wangyufen@huawei.com> --- tools/lib/bpf/libbpf.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 127a137bb6ba..565998539c09 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3217,6 +3217,9 @@ static int add_dummy_ksym_var(struct btf *btf) const struct btf_var_secinfo *vs; const struct btf_type *sec; + if (!btf) + return 0; + sec_btf_id = btf__find_by_name_kind(btf, KSYMS_SEC, BTF_KIND_DATASEC); if (sec_btf_id < 0) -- 2.20.1