CORE: various fixes for ucc_mem_map

[wfaderhold21]

What

Fix a collection of correctness bugs in the ucc_mem_map/ucc_mem_unmap path and specifically TL/UCP that can lead to failures or memory leaks.

[greptile-apps]

Greptile Summary

This PR fixes a collection of correctness bugs across ucc_mem_map/ucc_mem_unmap and TL/UCP: wrong tl_ctx[i]→tl_ctx[j] index and wrong base context in failed_mem_map, missing UCC_MEM_MAP_TL_NAME_LEN + sizeof(size_t) in the offload-import offset advance, NULL guard on tl_data before unmap, new IMPORT_OFFLOAD ucp_mem_unmap call, a separate tl_h allocation for the EXPORT_OFFLOAD result handle, and accumulated (non-early-return) error reporting in ucc_mem_unmap.

• tl_ucp_context.c: Offset bug in ucc_tl_ucp_mem_map_offload_import that caused the TL-name search to skip entries incorrectly is fixed; ucc_tl_ucp_mem_unmap now handles IMPORT_OFFLOAD and guards against NULL tl_data.
• ucc_context.c: Critical index/context/mode bugs in failed_mem_map are fixed; packed_buffers and tl_h allocations are sized with ucc_max; the EXPORT_OFFLOAD result handle gets its own tl_h allocation instead of aliasing the input handle's array.
• Three previously-flagged issues remain unresolved: (1) the packed_buffers array pointer itself is never freed in failed_pack; (2) in EXPORT_OFFLOAD mode, failed_pack's cleanup loop iterates j < i (importer counter) but packing stored at packed_buffers[tlh_index] (exporter slot), so any buffer stored at tlh_index >= i is silently leaked; (3) failed_mem_map unconditionally calls mem_unmap on and then frees local_memh even in EXPORT_OFFLOAD mode where local_memh is the caller's own handle.

Confidence Score: 3/5

The PR corrects several real bugs but leaves three unresolved issues in the EXPORT_OFFLOAD error paths that can cause memory leaks and corrupt the caller's handle on any pack failure.

Multiple issues remain open from the previous review round: the packed_buffers array pointer is never freed in failed_pack; the EXPORT_OFFLOAD cleanup loop uses the importer TL counter as the free index but packing stored at exporter-slot indices, leaking any buffer whose tlh_index >= i; and failed_mem_map frees local_memh and calls mem_unmap on its slots even in EXPORT_OFFLOAD mode where local_memh is the caller's own handle.

src/core/ucc_context.c — specifically the failed_pack / failed_mem_map labels in ucc_mem_map_export and their interaction with EXPORT_OFFLOAD mode

Important Files Changed

Filename	Overview
src/components/tl/ucp/tl_ucp_context.c	Fixes offset calculation in offload import, adds NULL guard on tl_data before unmap, adds IMPORT_OFFLOAD ucp_mem_unmap, sets NULLs after release to prevent double-free, and aligns alloc size to UCC_TL_UCP_MEMH_TL_HEADER_SIZE.
src/core/ucc_context.c	Fixes several correctness bugs (wrong tl_ctx index, wrong base context, wrong mode in failed_mem_map, tl_h alloc size, packed_buffers size, EXPORT_OFFLOAD tl_h now separately allocated); however, three previously-flagged P1 issues in the failed_pack/failed_mem_map EXPORT_OFFLOAD paths remain unfixed.

_{Reviews (3): Last reviewed commit: "TL/UCP: various memh fixes" | Re-trigger Greptile}