[PATCH 2/2] libbpf: Support repeated legacy kprobes on same function

[Qiang Wang]

If repeated legacy kprobes on same function in one process,
libbpf will register using the same probe name and got -EBUSY
error. So append index to the probe name format to fix this
problem.

Co-developed-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
Signed-off-by: Qiang Wang <wangqiang.wq.frank@xxxxxxxxxxxxx>
Signed-off-by: Chengming Zhou <zhouchengming@xxxxxxxxxxxxx>
---
 tools/lib/bpf/libbpf.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index b7d6c951fa09..0c41a45ffd54 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -9634,7 +9634,9 @@ static int append_to_file(const char *file, const char *fmt, ...)
 static void gen_kprobe_legacy_event_name(char *buf, size_t buf_sz,
 					 const char *kfunc_name, size_t offset)
 {
-	snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx", getpid(), kfunc_name, offset);
+	static int index = 0;
+	snprintf(buf, buf_sz, "libbpf_%u_%s_0x%zx_%d", getpid(), kfunc_name, offset
+		 __sync_fetch_and_add(&index, 1));
 }
 
 static int add_kprobe_event_legacy(const char *probe_name, bool retprobe,
-- 
2.20.1