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From: Jiri Olsa <olsajiri@gmail.com>
To: Yonghong Song <yonghong.song@linux.dev>
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>, Song Liu <song@kernel.org>,
	Quentin Monnet <quentin@isovalent.com>,
	bpf@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
	Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
	John Fastabend <john.fastabend@gmail.com>,
	KP Singh <kpsingh@chromium.org>,
	Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
	Yafang Shao <laoar.shao@gmail.com>
Subject: Re: [PATCHv3 bpf-next 6/6] bpftool: Add support to display uprobe_multi links
Date: Tue, 21 Nov 2023 12:35:12 +0100	[thread overview]
Message-ID: <ZVyV8JW29oXAKAlR@krava> (raw)
In-Reply-To: <769b00a5-88ac-4902-a69e-01ec977338ee@linux.dev>

On Mon, Nov 20, 2023 at 10:32:02AM -0800, Yonghong Song wrote:

SNIP

> > +static void show_uprobe_multi_plain(struct bpf_link_info *info)
> > +{
> > +	__u32 i;
> > +
> > +	if (!info->uprobe_multi.count)
> > +		return;
> > +
> > +	if (info->uprobe_multi.flags & BPF_F_UPROBE_MULTI_RETURN)
> > +		printf("\n\turetprobe.multi  ");
> > +	else
> > +		printf("\n\tuprobe.multi  ");
> > +
> > +	printf("path %s  ", (char *) u64_to_ptr(info->uprobe_multi.path));
> > +	printf("func_cnt %u  ", info->uprobe_multi.count);
> > +
> > +	if (info->uprobe_multi.pid != (__u32) -1)
> > +		printf("pid %d  ", info->uprobe_multi.pid);
> 
> Could you explain when info->uprobe_multi.pid could be -1?
> From patch 3, I see:
> 	info->uprobe_multi.pid = umulti_link->task ?
> 			 task_pid_nr_ns(umulti_link->task, task_active_pid_ns(current)) : 0;
> and cannot find how -1 could be assigned to info->uprobe_multi.pid.

ah it's leftover from previous version fix.. and I forgot to update
the bpftool code.. nice catch, thanks

jirka

> 
> > +
> > +	printf("\n\t%-16s   %-16s   %-16s", "offset", "ref_ctr_offset", "cookies");
> > +	for (i = 0; i < info->uprobe_multi.count; i++) {
> > +		printf("\n\t0x%-16llx 0x%-16llx 0x%-16llx",
> > +			u64_to_arr(info->uprobe_multi.offsets)[i],
> > +			u64_to_arr(info->uprobe_multi.ref_ctr_offsets)[i],
> > +			u64_to_arr(info->uprobe_multi.cookies)[i]);
> > +	}
> > +}
> > +
> >   static void show_perf_event_kprobe_plain(struct bpf_link_info *info)
> >   {
> >   	const char *buf;
> > [...]

      reply	other threads:[~2023-11-21 11:35 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-20 14:56 [PATCHv3 bpf-next 0/6] bpf: Add link_info support for uprobe multi link Jiri Olsa
2023-11-20 14:56 ` [PATCHv3 bpf-next 1/6] libbpf: Add st_type argument to elf_resolve_syms_offsets function Jiri Olsa
2023-11-20 14:56 ` [PATCHv3 bpf-next 2/6] bpf: Store ref_ctr_offsets values in bpf_uprobe array Jiri Olsa
2023-11-20 14:56 ` [PATCHv3 bpf-next 3/6] bpf: Add link_info support for uprobe multi link Jiri Olsa
2023-11-20 18:04   ` Yonghong Song
2023-11-22 21:50     ` Jiri Olsa
2023-11-23  9:20       ` Jiri Olsa
2023-11-23 18:26         ` Yonghong Song
2023-11-21 18:41   ` Andrii Nakryiko
2023-11-22 13:48     ` Jiri Olsa
2023-11-20 14:56 ` [PATCHv3 bpf-next 4/6] selftests/bpf: Use bpf_link__destroy in fill_link_info tests Jiri Olsa
2023-11-20 18:06   ` Yonghong Song
2023-11-20 14:56 ` [PATCHv3 bpf-next 5/6] selftests/bpf: Add link_info test for uprobe_multi link Jiri Olsa
2023-11-20 18:22   ` Yonghong Song
2023-11-21 11:29     ` Jiri Olsa
2023-11-20 14:56 ` [PATCHv3 bpf-next 6/6] bpftool: Add support to display uprobe_multi links Jiri Olsa
2023-11-20 18:32   ` Yonghong Song
2023-11-21 11:35     ` Jiri Olsa [this message]

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