Re: [PATCH RFC 2/5] bpf: Use file object build id in stackmap

Hao Luo
2023-02-09T07:24:11Z

On Wed, Feb 1, 2023 at 5:58 AM Jiri Olsa <jolsa@kernel.org> wrote:
>
> Use build id from file object in stackmap if it's available.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---

Can we insert the lookup from vma->vm_file in build_id_parse() rather
than its callers?

> kernel/bpf/stackmap.c | 8 ++++++++
> 1 file changed, 8 insertions(+)
>
> diff --git a/kernel/bpf/stackmap.c b/kernel/bpf/stackmap.c
> index aecea7451b61..944cb260a42c 100644
> --- a/kernel/bpf/stackmap.c
> +++ b/kernel/bpf/stackmap.c
> @@ -156,7 +156,15 @@ static void stack_map_get_build_id_offset(struct bpf_stack_build_id *id_offs,
> goto build_id_valid;
> }
> vma = find_vma(current->mm, ips[i]);
> +#ifdef CONFIG_FILE_BUILD_ID
> + if (vma && vma->vm_file && vma->vm_file->f_bid) {
> + memcpy(id_offs[i].build_id,
> + vma->vm_file->f_bid->data,
> + vma->vm_file->f_bid->sz);
> + } else {
> +#else
> if (!vma || build_id_parse(vma, id_offs[i].build_id, NULL)) {
> +#endif
> /* per entry fall back to ips */
> id_offs[i].status = BPF_STACK_BUILD_ID_IP;
> id_offs[i].ip = ips[i];
> --
> 2.39.1
>