Signed-off-by: Daniel Xu <dxu@xxxxxxxxx>
---
.../selftests/bpf/prog_tests/attach_probe.c | 32 ++++++++++++++++++-
1 file changed, 31 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
index 5ecc267d98b0..3d636cccb6dc 100644
--- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
+++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
@@ -1,6 +1,11 @@
// SPDX-License-Identifier: GPL-2.0
#include <test_progs.h>
+struct perf_read_output {
+ u64 count;
+ u64 lost;
+};
+
ssize_t get_base_addr() {
size_t start;
char buf[256];
@@ -32,6 +37,8 @@ void test_attach_probe(void)
const char *file = "./test_attach_probe.o";
struct bpf_program *kprobe_prog, *kretprobe_prog;
struct bpf_program *uprobe_prog, *uretprobe_prog;
+ struct perf_read_output kprobe_read_output;
+ const struct bpf_link_fd *kprobe_fd_link;
struct bpf_object *obj;
int err, prog_fd, duration = 0, res;
struct bpf_link *kprobe_link = NULL;
@@ -40,7 +47,8 @@ void test_attach_probe(void)
struct bpf_link *uretprobe_link = NULL;
int results_map_fd;
size_t uprobe_offset;
- ssize_t base_addr;
+ ssize_t base_addr, nread;
+ int kprobe_fd;
base_addr = get_base_addr();
if (CHECK(base_addr < 0, "get_base_addr",
@@ -116,6 +124,28 @@ void test_attach_probe(void)
/* trigger & validate kprobe && kretprobe */
usleep(1);
+ kprobe_fd_link = bpf_link__as_fd(kprobe_link);
+ if (CHECK(!kprobe_fd_link, "kprobe_link_as_fd",
+ "failed to cast link to fd link\n"))
+ goto cleanup;
+
+ kprobe_fd = bpf_link_fd__fd(kprobe_fd_link);
+ if (CHECK(kprobe_fd < 0, "kprobe_get_perf_fd",
+ "failed to get perf fd from kprobe link\n"))
+ goto cleanup;
+
+ /* Set to unexpected value so we can check the read(2) did stuff */
+ kprobe_read_output.lost = 1;
+ nread = read(kprobe_fd, &kprobe_read_output,
+ sizeof(kprobe_read_output));
+ if (CHECK(nread != sizeof(kprobe_read_output), "kprobe_perf_read",
+ "failed to read from perf fd\n"))
+ goto cleanup;
+ if (CHECK(kprobe_read_output.lost != 0, "kprobe_lost",
+ "read wrong value from perf fd: %lu\n",
+ kprobe_read_output.lost))
+ goto cleanup;
+
err = bpf_map_lookup_elem(results_map_fd, &kprobe_idx, &res);
if (CHECK(err, "get_kprobe_res",
"failed to get kprobe res: %d\n", err))
--
2.21.0
