Fix panic on duplicate PROFILER init

[dmonakhov]

CoMMA panics when NCCL communicators are created and destroyed in cycles
(e.g., pytest parametrized tests, training frameworks that recreate process
groups). This affects NCCL 2.27+ which changed profiler API behavior.

Environment

• NCCL version: 2.28.9+cuda12.9 (also affects 2.27.x)
• CoMMA commit: 1b2b374 (latest as of 2025-12-05)

reproducer_minimal.cpp

// Reproducer: CoMMA panic on init/destroy cycle (NCCL 2.27+)
// Build: nvcc -o reproducer reproducer_minimal.cpp -lnccl -lcudart
// Run: NCCL_PROFILER_PLUGIN_PATH=libnccl_profiler.so ./reproducer
#include <cuda_runtime.h>
#include <nccl.h>
#include <stdio.h>

int main() {
    cudaSetDevice(0);
    for (int i = 0; i < 3; i++) {
        ncclUniqueId id;
        ncclComm_t comm;
        ncclGetUniqueId(&id);
        printf("Cycle %d: init...", i + 1);
        ncclCommInitRank(&comm, 1, id, 0);  // Panics on cycle 2 with buggy CoMMA
        printf(" destroy...");
        ncclCommDestroy(comm);
        printf(" OK\n");
    }
    printf("SUCCESS\n");
    return 0;
}

Minimal reproducer_pytorch.py

"""
Reproducer: CoMMA panic on init/destroy cycle (NCCL 2.27+)
Run: NCCL_PROFILER_PLUGIN_PATH=libnccl_profiler.so python reproducer_pytorch.py
"""
import os
import torch
import torch.distributed as dist

os.environ.setdefault("MASTER_ADDR", "127.0.0.1")
os.environ.setdefault("MASTER_PORT", "29500")
os.environ.setdefault("RANK", "0")
os.environ.setdefault("WORLD_SIZE", "1")

for i in range(3):
    print(f"Cycle {i + 1}: init...", end="", flush=True)
    dist.init_process_group(backend="nccl", rank=0, world_size=1)
    # Force NCCL init with a collective op (PyTorch uses lazy init)
    t = torch.zeros(1, device="cuda")
    dist.all_reduce(t)
    print(" destroy...", end="", flush=True)
    dist.destroy_process_group()
    print(" OK")

print("SUCCESS")

[dmitry-monakhov]

Gentle ping. Can you please review this PR. it fixes real issue which prevent CoMMA to be used in faulty tolerant use-case where communicators are recreated