Commit 803f0700 authored by Tao Chen's avatar Tao Chen Committed by Alexei Starovoitov
Browse files

bpf: Show precise link_type for {uprobe,kprobe}_multi fdinfo 



Alexei suggested, 'link_type' can be more precise and differentiate
for human in fdinfo. In fact BPF_LINK_TYPE_KPROBE_MULTI includes
kretprobe_multi type, the same as BPF_LINK_TYPE_UPROBE_MULTI, so we
can show it more concretely.

link_type:	kprobe_multi
link_id:	1
prog_tag:	d2b307e915f0dd37
...
link_type:	kretprobe_multi
link_id:	2
prog_tag:	ab9ea0545870781d
...
link_type:	uprobe_multi
link_id:	9
prog_tag:	e729f789e34a8eca
...
link_type:	uretprobe_multi
link_id:	10
prog_tag:	7db356c03e61a4d4

Co-developed-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarJiri Olsa <jolsa@kernel.org>
Signed-off-by: default avatarTao Chen <chen.dylane@linux.dev>
Link: https://lore.kernel.org/r/20250702153958.639852-1-chen.dylane@linux.dev


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 1f24c0d8

include/linux/bpf.h

+1 −0
Original line number Diff line number Diff line
@@ -1702,6 +1702,7 @@ struct bpf_link { 
	 * link's semantics is determined by target attach hook

	 */

	bool sleepable;

	u32 flags;

	/* rcu is used before freeing, work can be used to schedule that

	 * RCU-based freeing before that, so they never overlap

	 */

kernel/bpf/syscall.c

+8 −1
Original line number Diff line number Diff line
@@ -3228,6 +3228,13 @@ static void bpf_link_show_fdinfo(struct seq_file *m, struct file *filp) 
	char prog_tag[sizeof(prog->tag) * 2 + 1] = { };



	if (type < ARRAY_SIZE(bpf_link_type_strs) && bpf_link_type_strs[type]) {

		if (link->type == BPF_LINK_TYPE_KPROBE_MULTI)

			seq_printf(m, "link_type:\t%s\n", link->flags == BPF_F_KPROBE_MULTI_RETURN ?

				   "kretprobe_multi" : "kprobe_multi");

		else if (link->type == BPF_LINK_TYPE_UPROBE_MULTI)

			seq_printf(m, "link_type:\t%s\n", link->flags == BPF_F_UPROBE_MULTI_RETURN ?

				   "uretprobe_multi" : "uprobe_multi");

		else

			seq_printf(m, "link_type:\t%s\n", bpf_link_type_strs[type]);

	} else {

		WARN_ONCE(1, "missing BPF_LINK_TYPE(...) for link type %u\n", type);

kernel/trace/bpf_trace.c

+4 −6
Original line number Diff line number Diff line
@@ -2466,7 +2466,6 @@ struct bpf_kprobe_multi_link { 
	u32 cnt;

	u32 mods_cnt;

	struct module **mods;

	u32 flags;

};



struct bpf_kprobe_multi_run_ctx {
@@ -2586,7 +2585,7 @@ static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link, 


	kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);

	info->kprobe_multi.count = kmulti_link->cnt;

	info->kprobe_multi.flags = kmulti_link->flags;

	info->kprobe_multi.flags = kmulti_link->link.flags;

	info->kprobe_multi.missed = kmulti_link->fp.nmissed;



	if (!uaddrs)
@@ -2976,7 +2975,7 @@ int bpf_kprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr 
	link->addrs = addrs;

	link->cookies = cookies;

	link->cnt = cnt;

	link->flags = flags;

	link->link.flags = flags;



	if (cookies) {

		/*
@@ -3045,7 +3044,6 @@ struct bpf_uprobe_multi_link { 
	struct path path;

	struct bpf_link link;

	u32 cnt;

	u32 flags;

	struct bpf_uprobe *uprobes;

	struct task_struct *task;

};
@@ -3109,7 +3107,7 @@ static int bpf_uprobe_multi_link_fill_link_info(const struct bpf_link *link, 


	umulti_link = container_of(link, struct bpf_uprobe_multi_link, link);

	info->uprobe_multi.count = umulti_link->cnt;

	info->uprobe_multi.flags = umulti_link->flags;

	info->uprobe_multi.flags = umulti_link->link.flags;

	info->uprobe_multi.pid = umulti_link->task ?

				 task_pid_nr_ns(umulti_link->task, task_active_pid_ns(current)) : 0;
@@ -3369,7 +3367,7 @@ int bpf_uprobe_multi_link_attach(const union bpf_attr *attr, struct bpf_prog *pr 
	link->uprobes = uprobes;

	link->path = path;

	link->task = task;

	link->flags = flags;

	link->link.flags = flags;



	bpf_link_init(&link->link, BPF_LINK_TYPE_UPROBE_MULTI,

		      &bpf_uprobe_multi_link_lops, prog);