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Merge branch 'bpf-retrieve-ref_ctr_offset-from-uprobe-perf-link'

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Jiri Olsa says:

====================
bpf: Retrieve ref_ctr_offset from uprobe perf link

hi,
adding ref_ctr_offset retrieval for uprobe perf link info.

v2 changes:
  - display ref_ctr_offset as hex number [Andrii]
  - added acks

thanks,
jirka
---
====================

Link: https://patch.msgid.link/20250509153539.779599-1-jolsa@kernel.org
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
This commit is contained in:
Andrii Nakryiko
2025-05-09 13:01:08 -07:00
parent cb4a119252 97596edfec
commit 5a8cb23161
6 changed files with 25 additions and 5 deletions
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1
include/uapi/linux/bpf.h
View File

@@ -6724,6 +6724,7 @@ struct bpf_link_info {
__u32 name_len;
__u32 offset; /* offset from file_name */
__u64 cookie;
__u64 ref_ctr_offset;
} uprobe; /* BPF_PERF_EVENT_UPROBE, BPF_PERF_EVENT_URETPROBE */
struct {
__aligned_u64 func_name; /* in/out */

5
kernel/bpf/syscall.c
View File

@@ -3800,14 +3800,14 @@ static int bpf_perf_link_fill_kprobe(const struct perf_event *event,
static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
struct bpf_link_info *info)
{
u64 ref_ctr_offset, offset;
char __user *uname;
u64 addr, offset;
u32 ulen, type;
int err;
uname = u64_to_user_ptr(info->perf_event.uprobe.file_name);
ulen = info->perf_event.uprobe.name_len;
err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &addr,
err = bpf_perf_link_fill_common(event, uname, &ulen, &offset, &ref_ctr_offset,
&type, NULL);
if (err)
return err;
@@ -3819,6 +3819,7 @@ static int bpf_perf_link_fill_uprobe(const struct perf_event *event,
info->perf_event.uprobe.name_len = ulen;
info->perf_event.uprobe.offset = offset;
info->perf_event.uprobe.cookie = event->bpf_cookie;
info->perf_event.uprobe.ref_ctr_offset = ref_ctr_offset;
return 0;
}
#endif

2
kernel/trace/trace_uprobe.c
View File

@@ -1489,7 +1489,7 @@ int bpf_get_uprobe_info(const struct perf_event *event, u32 *fd_type,
: BPF_FD_TYPE_UPROBE;
*filename = tu->filename;
*probe_offset = tu->offset;
*probe_addr = 0;
*probe_addr = tu->ref_ctr_offset;
return 0;
}
#endif /* CONFIG_PERF_EVENTS */

3
tools/bpf/bpftool/link.c
View File

@@ -380,6 +380,7 @@ show_perf_event_uprobe_json(struct bpf_link_info *info, json_writer_t *wtr)
u64_to_ptr(info->perf_event.uprobe.file_name));
jsonw_uint_field(wtr, "offset", info->perf_event.uprobe.offset);
jsonw_uint_field(wtr, "cookie", info->perf_event.uprobe.cookie);
jsonw_uint_field(wtr, "ref_ctr_offset", info->perf_event.uprobe.ref_ctr_offset);
}
static void
@@ -823,6 +824,8 @@ static void show_perf_event_uprobe_plain(struct bpf_link_info *info)
printf("%s+%#x ", buf, info->perf_event.uprobe.offset);
if (info->perf_event.uprobe.cookie)
printf("cookie %llu ", info->perf_event.uprobe.cookie);
if (info->perf_event.uprobe.ref_ctr_offset)
printf("ref_ctr_offset 0x%llx ", info->perf_event.uprobe.ref_ctr_offset);
}
static void show_perf_event_tracepoint_plain(struct bpf_link_info *info)

1
tools/include/uapi/linux/bpf.h
View File

@@ -6724,6 +6724,7 @@ struct bpf_link_info {
__u32 name_len;
__u32 offset; /* offset from file_name */
__u64 cookie;
__u64 ref_ctr_offset;
} uprobe; /* BPF_PERF_EVENT_UPROBE, BPF_PERF_EVENT_URETPROBE */
struct {
__aligned_u64 func_name; /* in/out */

18
tools/testing/selftests/bpf/prog_tests/fill_link_info.c
View File

@@ -37,6 +37,7 @@ static noinline void uprobe_func(void)
static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long addr,
ssize_t offset, ssize_t entry_offset)
{
ssize_t ref_ctr_offset = entry_offset /* ref_ctr_offset for uprobes */;
struct bpf_link_info info;
__u32 len = sizeof(info);
char buf[PATH_MAX];
@@ -97,6 +98,7 @@ static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long add
case BPF_PERF_EVENT_UPROBE:
case BPF_PERF_EVENT_URETPROBE:
ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
ASSERT_EQ(info.perf_event.uprobe.ref_ctr_offset, ref_ctr_offset, "uprobe_ref_ctr_offset");
ASSERT_EQ(info.perf_event.uprobe.name_len, strlen(UPROBE_FILE) + 1,
"name_len");
@@ -241,20 +243,32 @@ static void test_uprobe_fill_link_info(struct test_fill_link_info *skel,
.retprobe = type == BPF_PERF_EVENT_URETPROBE,
.bpf_cookie = PERF_EVENT_COOKIE,
);
const char *sema[1] = {
"uprobe_link_info_sema_1",
};
__u64 *ref_ctr_offset;
struct bpf_link *link;
int link_fd, err;
err = elf_resolve_syms_offsets("/proc/self/exe", 1, sema,
(unsigned long **) &ref_ctr_offset, STT_OBJECT);
if (!ASSERT_OK(err, "elf_resolve_syms_offsets_object"))
return;
opts.ref_ctr_offset = *ref_ctr_offset;
link = bpf_program__attach_uprobe_opts(skel->progs.uprobe_run,
0, /* self pid */
UPROBE_FILE, uprobe_offset,
&opts);
if (!ASSERT_OK_PTR(link, "attach_uprobe"))
return;
goto out;
link_fd = bpf_link__fd(link);
err = verify_perf_link_info(link_fd, type, 0, uprobe_offset, 0);
err = verify_perf_link_info(link_fd, type, 0, uprobe_offset, *ref_ctr_offset);
ASSERT_OK(err, "verify_perf_link_info");
bpf_link__destroy(link);
out:
free(ref_ctr_offset);
}
static int verify_kmulti_link_info(int fd, bool retprobe, bool has_cookies)