On Sun, May 28, 2023 at 02:20:21PM +0000, Yafang Shao wrote:
SNIP
> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 0d84a7a..00a0009 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -2564,10 +2564,41 @@ static void bpf_kprobe_multi_link_show_fdinfo(const struct bpf_link *link,
> }
> }
>
> +static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link,
> + struct bpf_link_info *info)
> +{
> + struct bpf_kprobe_multi_link *kmulti_link;
> + u64 *uaddrs = u64_to_user_ptr(info->kprobe_multi.addrs);
> + u32 ucount = info->kprobe_multi.count;
> + int i;
> +
> + if (!uaddrs ^ !ucount)
> + return -EINVAL;
> +
> + kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);
> + if (!uaddrs) {
> + info->kprobe_multi.count = kmulti_link->cnt;
> + return 0;
> + }
> +
> + if (!ucount)
> + return 0;
> +
> + if (ucount != kmulti_link->cnt)
> + return -EINVAL;
> +
> + for (i = 0; i < ucount; i++)
> + if (copy_to_user(uaddrs + i, kmulti_link->addrs + i,
> + sizeof(u64)))
> + return -EFAULT;
let's use put_user instead copy_to_user? or even better why not
copy that with single copy_to_user from kmulti_link->addrs
jirka
> + return 0;
> +}
> +
> static const struct bpf_link_ops bpf_kprobe_multi_link_lops = {
> .release = bpf_kprobe_multi_link_release,
> .dealloc = bpf_kprobe_multi_link_dealloc,
> .show_fdinfo = bpf_kprobe_multi_link_show_fdinfo,
> + .fill_link_info = bpf_kprobe_multi_link_fill_link_info,
> };
>
> static void bpf_kprobe_multi_cookie_swap(void *a, void *b, int size, const void *priv)
> diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
> index 9273c65..6be9b1d 100644
> --- a/tools/include/uapi/linux/bpf.h
> +++ b/tools/include/uapi/linux/bpf.h
> @@ -6434,6 +6434,10 @@ struct bpf_link_info {
> __s32 priority;
> __u32 flags;
> } netfilter;
> + struct {
> + __aligned_u64 addrs;
> + __u32 count;
> + } kprobe_multi;
> };
> } __attribute__((aligned(8)));
>
> --
> 1.8.3.1
>
