On Thu, Jan 18, 2024 at 5:54 PM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
>
> Storing cookies in kprobe_multi bpf_link_info data. The cookies
> field is optional and if provided it needs to be an array of
> __u64 with kprobe_multi.count length.
>
> Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
LGTM.
Acked-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> ---
> include/uapi/linux/bpf.h | 1 +
> kernel/trace/bpf_trace.c | 15 +++++++++++++++
> tools/include/uapi/linux/bpf.h | 1 +
> 3 files changed, 17 insertions(+)
>
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index b823d367a83c..199cb93dca7f 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -6563,6 +6563,7 @@ struct bpf_link_info {
> __u32 count; /* in/out: kprobe_multi function count */
> __u32 flags;
> __u64 missed;
> + __aligned_u64 cookies;
> } kprobe_multi;
> struct {
> __aligned_u64 path;
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 7ac6c52b25eb..c98c20abaf99 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2679,6 +2679,7 @@ static void bpf_kprobe_multi_link_dealloc(struct bpf_link *link)
> static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link,
> struct bpf_link_info *info)
> {
> + u64 __user *ucookies = u64_to_user_ptr(info->kprobe_multi.cookies);
> u64 __user *uaddrs = u64_to_user_ptr(info->kprobe_multi.addrs);
> struct bpf_kprobe_multi_link *kmulti_link;
> u32 ucount = info->kprobe_multi.count;
> @@ -2686,6 +2687,8 @@ static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link,
>
> if (!uaddrs ^ !ucount)
> return -EINVAL;
> + if (ucookies && !ucount)
> + return -EINVAL;
>
> kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);
> info->kprobe_multi.count = kmulti_link->cnt;
> @@ -2699,6 +2702,18 @@ static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link,
> else
> ucount = kmulti_link->cnt;
>
> + if (ucookies) {
> + if (kmulti_link->cookies) {
> + if (copy_to_user(ucookies, kmulti_link->cookies, ucount * sizeof(u64)))
> + return -EFAULT;
> + } else {
> + for (i = 0; i < ucount; i++) {
> + if (put_user(0, ucookies + i))
> + return -EFAULT;
> + }
> + }
> + }
> +
> if (kallsyms_show_value(current_cred())) {
> if (copy_to_user(uaddrs, kmulti_link->addrs, ucount * sizeof(u64)))
> return -EFAULT;
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index b823d367a83c..199cb93dca7f 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -6563,6 +6563,7 @@ struct bpf_link_info {
> __u32 count; /* in/out: kprobe_multi function count */
> __u32 flags;
> __u64 missed;
> + __aligned_u64 cookies;
> } kprobe_multi;
> struct {
> __aligned_u64 path;
> --
> 2.43.0
>
--
Regards
Yafang
