2.18.3-1

Fix data corruption with Tree/LL128 on systems with 1GPU:1NIC.
Fix hang with Collnet on bfloat16 on systems with less than one NIC
per GPU.
Fix long initialization time.
Fix data corruption with Collnet when mixing multi-process and
multi-GPU per process.
Fix crash when shared memory creation fails.
Fix Avg operation with Collnet/Chain.
Fix performance of alltoall at scale with more than one NIC per GPU.
Fix performance for DGX H800.
Fix race condition in connection progress causing a crash.
Fix network flush with Collnet.
Fix performance of aggregated allGather/reduceScatter operations.
Fix PXN operation when CUDA_VISIBLE_DEVICES is set.
Fix NVTX3 compilation issues on Debian 10.

src/misc/shmutils.cc

@@ -32,7 +32,7 @@ static void shmHandleInit(int fd, char* shmPath, size_t shmSize, size_t realShmS
   handle->devShmPtr = dptr;
   handle->shmSize = shmSize;
   handle->realShmSize = realShmSize;
-  handle->refcount = (int*)(hptr + shmSize);
+  handle->refcount = (hptr != NULL) ? (int*)(hptr + shmSize) : NULL;
   if (create) {
     int slen = strlen(shmPath);
     handle->shmPath = (char*)malloc(slen + 1);
@@ -81,6 +81,7 @@ ncclResult_t ncclShmOpen(char* shmPath, size_t shmSize, void** shmPtr, void** de
   if (hptr == MAP_FAILED) {
     WARN("Could not map %s size %zi, error: %s", shmPath, realShmSize, strerror(errno));
     ret = ncclSystemError;
+    hptr = NULL;
     goto fail;
   }
 
@@ -125,7 +126,7 @@ ncclResult_t ncclShmClose(ncclShmHandle_t handle) {
   if (tmphandle) {
     if (tmphandle->fd >= 0) {
       close(tmphandle->fd);
-      if (tmphandle->shmPath != NULL && *tmphandle->refcount > 0) {
+      if (tmphandle->shmPath != NULL && tmphandle->refcount != NULL && *tmphandle->refcount > 0) {
         if (unlink(tmphandle->shmPath) != 0) {
           WARN("unlink shared memory %s failed, error: %s", tmphandle->shmPath, strerror(errno));
           ret = ncclSystemError;