From 9fd112b1f82b587ffb12fb67dd032f551fdb571a Mon Sep 17 00:00:00 2001
From: Jiri Olsa <jolsa@kernel.org>
Date: Fri, 19 Jan 2024 12:04:59 +0100
Subject: [PATCH] bpf: Store cookies in kprobe_multi bpf_link_info data
Storing cookies in kprobe_multi bpf_link_info data. The cookies
field is optional and if provided it needs to be an array of
__u64 with kprobe_multi.count length.
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20240119110505.400573-3-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
---
include/uapi/linux/bpf.h | 1 +
kernel/trace/bpf_trace.c | 15 +++++++++++++++
tools/include/uapi/linux/bpf.h | 1 +
3 files changed, 17 insertions(+)
diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
index 181e744332729..287d05732668f 100644
--- a/include/uapi/linux/bpf.h
+++ b/include/uapi/linux/bpf.h
@@ -6563,6 +6563,7 @@ struct bpf_link_info {
__u32 count; /* in/out: kprobe_multi function count */
__u32 flags;
__u64 missed;
+ __aligned_u64 cookies;
} kprobe_multi;
struct {
__aligned_u64 path;
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c
index 7ac6c52b25ebc..c98c20abaf99d 100644
--- a/kernel/trace/bpf_trace.c
+++ b/kernel/trace/bpf_trace.c
@@ -2679,6 +2679,7 @@ static void bpf_kprobe_multi_link_dealloc(struct bpf_link *link)
static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link,
struct bpf_link_info *info)
{
+ u64 __user *ucookies = u64_to_user_ptr(info->kprobe_multi.cookies);
u64 __user *uaddrs = u64_to_user_ptr(info->kprobe_multi.addrs);
struct bpf_kprobe_multi_link *kmulti_link;
u32 ucount = info->kprobe_multi.count;
@@ -2686,6 +2687,8 @@ static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link,
if (!uaddrs ^ !ucount)
return -EINVAL;
+ if (ucookies && !ucount)
+ return -EINVAL;
kmulti_link = container_of(link, struct bpf_kprobe_multi_link, link);
info->kprobe_multi.count = kmulti_link->cnt;
@@ -2699,6 +2702,18 @@ static int bpf_kprobe_multi_link_fill_link_info(const struct bpf_link *link,
else
ucount = kmulti_link->cnt;
+ if (ucookies) {
+ if (kmulti_link->cookies) {
+ if (copy_to_user(ucookies, kmulti_link->cookies, ucount * sizeof(u64)))
+ return -EFAULT;
+ } else {
+ for (i = 0; i < ucount; i++) {
+ if (put_user(0, ucookies + i))
+ return -EFAULT;
+ }
+ }
+ }
+
if (kallsyms_show_value(current_cred())) {
if (copy_to_user(uaddrs, kmulti_link->addrs, ucount * sizeof(u64)))
return -EFAULT;
diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h
index 181e744332729..287d05732668f 100644
--- a/tools/include/uapi/linux/bpf.h
+++ b/tools/include/uapi/linux/bpf.h
@@ -6563,6 +6563,7 @@ struct bpf_link_info {
__u32 count; /* in/out: kprobe_multi function count */
__u32 flags;
__u64 missed;
+ __aligned_u64 cookies;
} kprobe_multi;
struct {
__aligned_u64 path;
--
2.30.2