On Fri, Jul 7, 2023 at 6:00 AM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
>
> On Wed, Jun 28, 2023 at 4:53 AM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
> >
> > With the addition of support for fill_link_info to the kprobe_multi link,
> > users will gain the ability to inspect it conveniently using the
> > `bpftool link show`. This enhancement provides valuable information to the
> > user, including the count of probed functions and their respective
> > addresses. It's important to note that if the kptr_restrict setting is not
> > permitted, the probed address will not be exposed, ensuring security.
> >
> > Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> > ---
>
> documentation nit, but otherwise LGTM
>
> Also, looking at other patch where you introduce bpf_copy_user(),
> seems like we return -ENOSPC when user-provided memory is not big
> enough. So let's change E2BIG in this patch to ENOSPC?
Sure. Will change it.
>
>
> Acked-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Thanks for your review.
>
> > include/uapi/linux/bpf.h | 5 +++++
> > kernel/trace/bpf_trace.c | 37 ++++++++++++++++++++++++++++++++++
> > tools/include/uapi/linux/bpf.h | 5 +++++
> > 3 files changed, 47 insertions(+)
> >
> > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> > index 60a9d59beeab..512ba3ba2ed3 100644
> > --- a/include/uapi/linux/bpf.h
> > +++ b/include/uapi/linux/bpf.h
> > @@ -6439,6 +6439,11 @@ struct bpf_link_info {
> > __s32 priority;
> > __u32 flags;
> > } netfilter;
> > + struct {
> > + __aligned_u64 addrs; /* in/out: addresses buffer ptr */
>
> addrs field itself is not modified, the memory it points to is
> modified, so it's not really in/out per se, it is just a pointer to
> memory where kernel stores output data
Thanks for the explanation. Will change it.
>
> > + __u32 count;
>
> but count field itself is in/out, so please add a comment explicitly
> stating this
Will do it.
--
Regards
Yafang
