Since an empty attach_prog_fd is no longer allowed when loading EXT bpf
program, to avoid BPF_PROG_TYPE_EXT type detection failure, just provide
a valid one before probing.
Signed-off-by: Tengda Wu <wutengda@xxxxxxxxxxxxxxx>
---
tools/lib/bpf/libbpf_probes.c | 13 ++++++++++++-
1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/tools/lib/bpf/libbpf_probes.c b/tools/lib/bpf/libbpf_probes.c
index 9dfbe7750f56..2b09acc81be7 100644
--- a/tools/lib/bpf/libbpf_probes.c
+++ b/tools/lib/bpf/libbpf_probes.c
@@ -112,6 +112,7 @@ static int probe_prog_load(enum bpf_prog_type prog_type,
int fd, err, exp_err = 0;
const char *exp_msg = NULL;
char buf[4096];
+ int attach_prog_fd = -1;
switch (prog_type) {
case BPF_PROG_TYPE_CGROUP_SOCK_ADDR:
@@ -148,9 +149,17 @@ static int probe_prog_load(enum bpf_prog_type prog_type,
opts.log_size = sizeof(buf);
opts.log_level = 1;
opts.attach_btf_id = 1;
+ /* use socket_filter as the target program to attach, because it
+ * is the earliest and most likely BPF program to be supported.
+ */
+ attach_prog_fd = bpf_prog_load(BPF_PROG_TYPE_SOCKET_FILTER, NULL,
+ "GPL", insns, insns_cnt, NULL);
+ if (attach_prog_fd < 0)
+ return attach_prog_fd;
+ opts.attach_prog_fd = attach_prog_fd;
exp_err = -EINVAL;
- exp_msg = "Cannot replace kernel functions";
+ exp_msg = "FENTRY/FEXIT program can only be attached to another program annotated with BTF";
break;
case BPF_PROG_TYPE_SYSCALL:
opts.prog_flags = BPF_F_SLEEPABLE;
@@ -192,6 +201,8 @@ static int probe_prog_load(enum bpf_prog_type prog_type,
err = -errno;
if (fd >= 0)
close(fd);
+ if (attach_prog_fd >= 0)
+ close(attach_prog_fd);
if (exp_err) {
if (fd >= 0 || err != exp_err)
return 0;
--
2.34.1
