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

[Jiri Olsa <olsajiri@gmail.com>]

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;
>  		}