[BUG] uretprobe improperly when attaching two programs onto the same function

[Officeyutong]

Attach the following program:

// SPDX-License-Identifier: GPL-2.0
#include <vmlinux.h>
#include <bpf/bpf_helpers.h>
#include <bpf/bpf_tracing.h>
SEC("uretprobe/./example/simple_uretprobe_test/victim:simple_add")
int BPF_URETPROBE(simple_probe, long ret)
{
	bpf_printk("Ret=%ld\n", ret);

	return 0;
}

SEC("uretprobe/./example/simple_uretprobe_test/victim:simple_add")
int BPF_URETPROBE(simple_probe2, long ret)
{
	bpf_printk("Ret2=%ld\n", ret);

	return 0;
}

char LICENSE[] SEC("license") = "GPL";

victim:

#include <cstdint>
#include <fcntl.h>
#include <iostream>
#include <ostream>
#include <unistd.h>

extern "C" int64_t simple_add(int64_t a, int64_t b)
{
	return a + b;
}

int main()
{
	while (true) {
		for (int i = 1; i <= 10; i++) {
			for (int j = 1; j <= 10; j++) {
				int32_t ret = simple_add(i, j);
				std::cout << i << " + " << j << " = " << ret
					  << std::endl;
				usleep(1000 * 500);
			}
		}
	}
	return 0;
}

Will lead to the following output:

Ret2=1
Ret=2
1 + 1 = 2
Ret2=1
Ret=3
1 + 2 = 3
Ret2=1
Ret=4
1 + 3 = 4
Ret2=1
Ret=5
1 + 4 = 5

Where ret2 prints the first argument, not the return value, so it seems to be attached as uprobe