From: Wei Fu fuweid89@gmail.com
[ Upstream commit 0991f6a38f576aa9a5e34713e23c998a3310d4d0 ]
After `bpftool gen skeleton`, the ${bpf_app}.skel.h will provide that ${bpf_app_name}__open helper to load bpf. If there is some error like ENOMEM, the ${bpf_app_name}__open will rollback(free) the allocated object, including `bpf_object_skeleton`.
Since the ${bpf_app_name}__create_skeleton set the obj->skeleton first and not rollback it when error, it will cause double-free in ${bpf_app_name}__destory at ${bpf_app_name}__open. Therefore, we should set the obj->skeleton before return 0;
Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton") Signed-off-by: Wei Fu fuweid89@gmail.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20220108084008.1053111-1-fuweid89@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- tools/bpf/bpftool/gen.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 5c18351290f0..587027050f43 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -928,7 +928,6 @@ static int do_skeleton(int argc, char **argv) s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\ if (!s) \n\ goto err; \n\ - obj->skeleton = s; \n\ \n\ s->sz = sizeof(*s); \n\ s->name = "%1$s"; \n\ @@ -1001,6 +1000,7 @@ static int do_skeleton(int argc, char **argv) \n\ s->data = (void *)%2$s__elf_bytes(&s->data_sz); \n\ \n\ + obj->skeleton = s; \n\ return 0; \n\ err: \n\ bpf_object__destroy_skeleton(s); \n\