Re: [PATCH 3/3] uprobes: make uprobe_register() return struct uprobe *

[Jiri Olsa]

On Wed, Jul 10, 2024 at 06:31:33PM +0200, Oleg Nesterov wrote:

SNIP

> diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
> index 467f358c8ce7..7571811127a2 100644
> --- a/kernel/trace/bpf_trace.c
> +++ b/kernel/trace/bpf_trace.c
> @@ -3157,6 +3157,7 @@ struct bpf_uprobe {
>       loff_t offset;
>       unsigned long ref_ctr_offset;
>       u64 cookie;
> +     struct uprobe *uprobe;
>       struct uprobe_consumer consumer;
>  };
>  
> @@ -3180,10 +3181,8 @@ static void bpf_uprobe_unregister(struct path *path, 
> struct bpf_uprobe *uprobes,
>  {
>       u32 i;
>  
> -     for (i = 0; i < cnt; i++) {
> -             uprobe_unregister(d_real_inode(path->dentry), uprobes[i].offset,
> -                               &uprobes[i].consumer);
> -     }

nice, we could also drop path argument now

jirka

> +     for (i = 0; i < cnt; i++)
> +             uprobe_unregister(uprobes[i].uprobe, &uprobes[i].consumer);
>  }
>  
>  static void bpf_uprobe_multi_link_release(struct bpf_link *link)
> @@ -3477,11 +3476,12 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr 
> *attr, struct bpf_prog *pr
>                     &bpf_uprobe_multi_link_lops, prog);
>  
>       for (i = 0; i < cnt; i++) {
> -             err = uprobe_register(d_real_inode(link->path.dentry),
> +             uprobes[i].uprobe = 
> uprobe_register(d_real_inode(link->path.dentry),
>                                            uprobes[i].offset,
>                                            uprobes[i].ref_ctr_offset,
>                                            &uprobes[i].consumer);
> -             if (err) {
> +             if (IS_ERR(uprobes[i].uprobe)) {
> +                     err = PTR_ERR(uprobes[i].uprobe);
>                       bpf_uprobe_unregister(&path, uprobes, i);
>                       goto error_free;
>               }