Commit 51a33c60 authored by Qiang Wang's avatar Qiang Wang Committed by Andrii Nakryiko
Browse files

libbpf: Support repeated legacy kprobes on same function 



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: default avatarChengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: default avatarQiang Wang <wangqiang.wq.frank@bytedance.com>
Signed-off-by: default avatarChengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20211227130713.66933-2-wangqiang.wq.frank@bytedance.com
parent 71cff670

tools/lib/bpf/libbpf.c

+4 −1
Original line number Diff line number Diff line
@@ -9916,7 +9916,10 @@ 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,