bpf: Add missed value to kprobe_multi link info

Add missed value to kprobe_multi link info to hold the stats of missed kprobe_multi probe. The missed counter gets incremented when fprobe fails the recursion check or there's no rethook available for return probe. In either case the attached bpf program is not executed.

Jiri Olsa committed 3 years ago

Commit e2b2cd51 parent f915fcb3 files · +3 −0Browse files

Unified · Split

3 files

include/uapi/linux/bpf.h +1 −0
kernel/trace/bpf_trace.c +1 −0
tools/include/uapi/linux/bpf.h +1 −0

include/uapi/linux/bpf.h+1−0

@@ -6532,6 +6532,7 @@ struct bpf_link_info { · 6531 unmodified lines
6532	__aligned_u64 addrs;	6532	__aligned_u64 addrs;
6533	__u32 count; /* in/out: kprobe_multi function count */	6533	__u32 count; /* in/out: kprobe_multi function count */
6534	__u32 flags;	6534	__u32 flags;
		6535	__u64 missed;
6535	} kprobe_multi;	6536	} kprobe_multi;
6536	struct {	6537	struct {
6537	__u32 type; /* enum bpf_perf_event_type */	6538	__u32 type; /* enum bpf_perf_event_type */

kernel/trace/bpf_trace.c+1−0

@@ -2614,6 +2614,7 @@ static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link, · 2613 unmodified lines
2614	kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);	2614	kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);
2615	info->kprobe_multi.count = kmulti_link->cnt;	2615	info->kprobe_multi.count = kmulti_link->cnt;
2616	info->kprobe_multi.flags = kmulti_link->flags;	2616	info->kprobe_multi.flags = kmulti_link->flags;
		2617	info->kprobe_multi.missed = kmulti_link->fp.nmissed;
2617		2618
2618	if (!uaddrs)	2619	if (!uaddrs)
2619	return 0;	2620	return 0;

tools/include/uapi/linux/bpf.h+1−0

@@ -6532,6 +6532,7 @@ struct bpf_link_info { · 6531 unmodified lines
6532	__aligned_u64 addrs;	6532	__aligned_u64 addrs;
6533	__u32 count; /* in/out: kprobe_multi function count */	6533	__u32 count; /* in/out: kprobe_multi function count */
6534	__u32 flags;	6534	__u32 flags;
		6535	__u64 missed;
6535	} kprobe_multi;	6536	} kprobe_multi;
6536	struct {	6537	struct {
6537	__u32 type; /* enum bpf_perf_event_type */	6538	__u32 type; /* enum bpf_perf_event_type */