Python generator ref leak causing OOM cascade in model conversion

Summary#

When a lazy generator is stored as a value in a long-lived mapping (e.g., conversion_mapping), it holds references to all upstream tensors until the generator is exhausted or GC'd — not when the dict entry is read. In large-model pipelines this silently inflates peak RSS until the process OOMs, and the root cause is invisible in profilers that snapshot allocation sites rather than retention graphs.

Problem#

Generator object assigned to a dict value retains all closed-over tensor references. The dict outlives the generator's logical scope, so tensors are never released between conversion steps.

Solution#

Eagerly materialize generators at assignment (list(gen) or tuple(gen)), or explicitly close() the generator immediately after the last read. Audit any mapping whose values could be generator objects rather than concrete collections.

Failure Modes#

OOM only manifests at large model scale, not in unit tests with small checkpoints
Memory profilers report allocation site (creation), not retention site (dict), misleading root-cause analysis
Partial fix — materializing in one path but leaving another path with the same pattern — leaves a latent regression

Sources#

https://github.com/tensorflow/tensorflow/pull/127204
https://github.com/tensorflow/tensorflow/pull/127251
https://github.com/huggingface/transformers/pull/48516
https://github.com/huggingface/transformers/pull/48155
https://github.com/huggingface/transformers/pull/48685
https://github.com/huggingface/transformers/pull/40546
https://github.com/huggingface/transformers/pull/48720
https://github.com/huggingface/transformers/pull/48689
https://github.com/huggingface/transformers/pull/44314
https://github.com/huggingface/transformers/pull/46419
https://github.com/huggingface/transformers/pull/48684
https://github.com/microsoft/ML-For-Beginners/pull/1002
https://github.com/microsoft/ML-For-Beginners/pull/1001
https://github.com/microsoft/ML-For-Beginners/pull/1000
https://github.com/ClickHouse/ClickHouse/pull/117998
https://github.com/ClickHouse/ClickHouse/pull/117997
https://github.com/ClickHouse/ClickHouse/pull/119737
https://github.com/ClickHouse/ClickHouse/pull/118005
https://github.com/ClickHouse/ClickHouse/pull/118023
https://github.com/ClickHouse/ClickHouse/pull/119676
https://github.com/ClickHouse/ClickHouse/pull/118183
https://github.com/ClickHouse/ClickHouse/pull/118057
https://github.com/ClickHouse/ClickHouse/pull/118046
https://github.com/ClickHouse/ClickHouse/pull/118108
https://github.com/ClickHouse/ClickHouse/pull/118137
https://github.com/ClickHouse/ClickHouse/pull/119348
https://github.com/ClickHouse/ClickHouse/pull/118297
https://github.com/ClickHouse/ClickHouse/pull/118227
https://github.com/ClickHouse/ClickHouse/pull/118221
https://github.com/rustfs/rustfs/pull/7729
https://github.com/rustfs/rustfs/pull/7731
https://github.com/rustfs/rustfs/pull/7739
https://github.com/rustfs/rustfs/pull/7738
https://github.com/rustfs/rustfs/pull/7734
https://github.com/rustfs/rustfs/pull/7728
https://github.com/rustfs/rustfs/pull/7726
https://github.com/rustfs/rustfs/pull/7724
https://github.com/rustfs/rustfs/pull/7723
https://github.com/rustfs/rustfs/pull/7712
https://github.com/rustfs/rustfs/pull/7722
https://github.com/rustfs/rustfs/pull/7721
https://github.com/rustfs/rustfs/pull/7720
https://github.com/rustfs/rustfs/pull/7719
https://github.com/rustfs/rustfs/pull/7718
mined_at: 2026-09-13T07:06:13Z

Sagwan Revalidation 2026-09-13T07:44:48Z#

verdict: stale
note: 핵심 Python 동작 설명은 여전히 유효하나, 인용 소스 PR들이 모두 무관한 변경 사항을 가리켜 근거 링크가 사실상 무효화됨.