Prevent OOB write for RBK and RLE in streaming context

[nanan-nvidia]

Fixes #10036

[coderabbitai]

📝 Walkthrough

Summary by CodeRabbit

• Bug Fixes
  • Improved unique-count processing for partitioned data.
  • Prevented unnecessary updates to intermediate results after the final partition, improving correctness and consistency of streaming operations.

Walkthrough

Changes

Streaming unique-count handling

Layer / File(s)	Summary
Guard final-partition output writes cub/cub/device/dispatch/dispatch_reduce_by_key.cuh, cub/cub/device/dispatch/dispatch_rle.cuh	add_num_uniques writes the accumulated unique count only when the current partition is not the final partition.

Assessment against linked issues

Objective	Addressed	Explanation
Prevent the out-of-bounds write in streaming run-length encoding with 64-bit item counts and an unaligned temporary allocation [#10036]	✅

Suggested reviewers: bernhardmgruber, miscco, davebayer

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[coderabbitai]

🧹 Nitpick comments (1)

cub/cub/device/dispatch/dispatch_reduce_by_key.cuh (1)

105-109: 🩺 Stability & Availability | 🔵 Trivial | 🏗️ Heavy lift

suggestion: Add focused regression coverage for both streaming implementations using 64-bit num_items, a single partition, and an unaligned temporary-storage base, then run Compute Sanitizer. Ordinary output assertions may pass even if the zero-sized auxiliary buffer is still written.

• cub/cub/device/dispatch/dispatch_reduce_by_key.cuh#L105-L109: validate reduce-by-key output and sanitizer cleanliness.
• cub/cub/device/dispatch/dispatch_rle.cuh#L101-L105: validate RLE output and sanitizer cleanliness.
  This follows the PR objective of preventing silent out-of-bounds writes in these exact streaming paths.

Source: Path instructions

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📥 Commits

Reviewing files that changed from the base of the PR and between 02f4015 and 71ab377.

📒 Files selected for processing (2)

• cub/cub/device/dispatch/dispatch_reduce_by_key.cuh
• cub/cub/device/dispatch/dispatch_rle.cuh