Issues

• UCP/EP: failed ucp_ep_create leaks the lanes connected before the failing lane

  openucx/ucx#12021 · Filter by author vMaroon opened on Oct 3, 2026

• UCP/EP: flush-mode ucp_ep_close_nbx keeps worker-address endpoints to live peers until ucp_worker_destroy

  openucx/ucx#12020 · Filter by author vMaroon opened on Oct 3, 2026

• make dist silently produces an empty tarball when uid/gid exceeds the ustar limit

  Bug
  openucx/ucx#12018 · Filter by author kalvdans opened on Oct 2, 2026

• CUDA IPC-imported pointers (cuIpcOpenMemHandle) are not tracked by the memtype cache: host memcpy into device memory (SIGSEGV) on eager, and no fallback when registration fails on rendezvous

  Bug
  openucx/ucx#12013 · Filter by author bosilca opened on Oct 1, 2026

• Intra-Node Performance Degradation (due to multirail?)

  Bug
  openucx/ucx#11986 · Filter by author christgau opened on Sep 24, 2026

• CUDA IPC: support VMM POSIX FD sharing across PID namespaces

  openucx/ucx#11978 · Filter by author anandj91 opened on Sep 22, 2026

• rc_verbs on RoCE LAG bond: 23 GB/s → 2.9 MB/s after #11262 (ZTR-RTT CC enabled by default)

  openucx/ucx#11955 · Filter by author gugulee opened on Sep 16, 2026

• TCP: cannot be selected as an RMA BW lane with peer error handling, so ucp_put falls back to AM emulation

  openucx/ucx#11929 · Filter by author maorv opened on Sep 8, 2026
  1

• Segfault when operating on HIP asynchronously allocated memory on ROCm 10.0.0

  Bug
  openucx/ucx#11898 · Filter by author maartenarnst opened on Sep 4, 2026

• uct_iface_open failure on unusable RDMA device aborts entire worker instead of skipping

  Bug
  openucx/ucx#11820 · Filter by author evacchi opened on Aug 24, 2026

• UCP/WIREUP: are misaligned typed accesses in packed addresses intentional?

  Bug
  openucx/ucx#11806 · Filter by author yqtian-se opened on Aug 20, 2026

• cuda_ipc: imported remote mappings are never released until importer process exit (no per-peer eviction) — pins exporter VMM/fabric memory domain-wide

  openucx/ucx#11753 · Filter by author 404mario opened on Aug 11, 2026
  11

• UCT/IB/MLX5: Should rc_mlx5 support bounded batch CQ draining?

  openucx/ucx#11729 · Filter by author Zacky-ran opened on Aug 5, 2026

• UCT/IB/MLX5: Non-DevX rc_mlx5 CQ notification misses after Direct Verbs polling

  Bug
  openucx/ucx#11728 · Filter by author Zacky-ran opened on Aug 5, 2026
  2

  

• UMR QP INIT2RTR fails on LAG-bonded devices, causing segfault on memory registration

  Bug
  openucx/ucx#11709 · Filter by author Bowser1704 opened on Jul 31, 2026

• #11547 concentrates multi-rank GPU RMA traffic onto a subset of NICs (4 of 8), causing severe oversubscription and multi-× bandwidth loss

  Bug
  openucx/ucx#11680 · Filter by author bosilca opened on Jul 20, 2026
  2

  

• cuda_copy transport in UCX_TLS degrades LLM inference throughput

  openucx/ucx#11652 · Filter by author UnpureRationalist opened on Jul 14, 2026
  3

• Version 1.21.0 does not build without gpunetio

  Bug
  openucx/ucx#11591 · Filter by author lahwaacz opened on Jun 25, 2026

• Feature request: allow UCP AMO offload for partially capable UCT atomic masks

  openucx/ucx#11572 · Filter by author sgomw opened on Jun 23, 2026

• UCS/VFS: stale/freed node access when refresh_cb removes the current node or parent

  Bug
  openucx/ucx#11568 · Filter by author Zacky-ran opened on Jun 22, 2026

• mlx5: ZTR-RTT CC is not enabled by default when DEVX=try (unlike DEVX=no)

  Bug
  openucx/ucx#11558 · Filter by author kimullaa opened on Jun 16, 2026

• Question about namespace requirements for UCX posix shm in a host <-> isolated-container deployment

  openucx/ucx#11546 · Filter by author reverseW opened on Jun 10, 2026

• UD: control skb reuse before CQE in uct_ud_ep_purge_outstanding()

  openucx/ucx#11544 · Filter by author hyeonseong-choi opened on Jun 10, 2026

• TCP chosen over CUDA COPY on the same host.

  openucx/ucx#11487 · Filter by author DevUt opened on May 26, 2026

• ucx_perftest tag_bw -m cuda shows phase-changing bandwidth and stalls for large CUDA messages on single-node GPU pair

  Bug
  openucx/ucx#11476 · Filter by author CyberSecurityErial opened on May 21, 2026