bpftool: Only set obj->skeleton on complete success
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 ${bpf_app_name}__open. Therefore, we should
set the obj->skeleton before return 0;
Fixes: 5dc7a8b21144 ("bpftool, selftests/bpf: Embed object file inside skeleton")
Signed-off-by: Wei Fu <[email protected]>
Signed-off-by: Andrii Nakryiko <[email protected]>
Link: https://lore.kernel.org/bpf/[email protected]
diff --git a/src/gen.c b/src/gen.c
index b4695df..a7387c2 100644
--- a/src/gen.c
+++ b/src/gen.c
@@ -927,7 +927,6 @@
s = (struct bpf_object_skeleton *)calloc(1, sizeof(*s));\n\
if (!s) \n\
goto err; \n\
- obj->skeleton = s; \n\
\n\
s->sz = sizeof(*s); \n\
s->name = \"%1$s\"; \n\
@@ -1000,6 +999,7 @@
\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\
