[PATCH AUTOSEL 6.4 35/41] libbpf: Free btf_vmlinux when closing bpf_object

Sasha Levin
2023-09-08T18:21:09Z

From: Hao Luo <haoluo@google.com>

[ Upstream commit 29d67fdebc42af6466d1909c60fdd1ef4f3e5240 ]

I hit a memory leak when testing bpf_program__set_attach_target().
Basically, set_attach_target() may allocate btf_vmlinux, for example,
when setting attach target for bpf_iter programs. But btf_vmlinux
is freed only in bpf_object_load(), which means if we only open
bpf object but not load it, setting attach target may leak
btf_vmlinux.

So let's free btf_vmlinux in bpf_object__close() anyway.

Signed-off-by: Hao Luo <haoluo@google.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230822193840.1509809-1-haoluo@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/lib/bpf/libbpf.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index a27f6e9ccce75..29b9f223e0f93 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -8328,6 +8328,7 @@ void bpf_object__close(struct bpf_object *obj)
bpf_object__elf_finish(obj);
bpf_object_unload(obj);
btf__free(obj->btf);
+ btf__free(obj->btf_vmlinux);
btf_ext__free(obj->btf_ext);

for (i = 0; i < obj->nr_maps; i++)
--
2.40.1