On 8/21/24 6:31 AM, Ma Ke wrote:
bpf_object__btf() can return NULL value. If bpf_object__btf returns null, do not progress through codegen_subskel_datasecs(). This avoids a null ptr dereference.
Found by code review, complie tested only.
Do you have a real case to show null ptr reference here? Code review and compile test are not enough. You should have a real reproducible case before you send the patch.
For this particular case, we have check
btf = bpf_object__btf(obj); if (!btf) { err = -1; p_err("need btf type information for %s", obj_name); goto out; }
which ensures that btf is available before codegen for subskeleton, so what you described won't happen in practice.
Cc: stable@vger.kernel.org Fixes: 00389c58ffe9 ("bpftool: Add support for subskeletons") Signed-off-by: Ma Ke make24@iscas.ac.cn
tools/bpf/bpftool/gen.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index 5a4d3240689e..7ce62f280310 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -334,6 +334,9 @@ static int codegen_subskel_datasecs(struct bpf_object *obj, const char *obj_name const char *sec_name, *var_name; __u32 var_type_id;
- if (!btf)
return -EINVAL;- d = btf_dump__new(btf, codegen_btf_dump_printf, NULL, NULL); if (!d) return -errno;