Fix memory pointer overflow in Mamba state buffers

[srajabos]

Device memory addresses can exceed the signed int64 maximum value
(2^63-1), causing pointer overflow errors when creating Mamba state
buffers for copy operations.

Use torch.uint64 unconditionally for src_ptrs and dst_ptrs to support
the full 64-bit unsigned address space (max 2^64-1) on all platforms.

Tested with: Qwen3-Coder-Next-FP8

Purpose

Test Plan

Test Result

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[claude]

Claude Code Review

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[mergify]

Hi @srajabos, the pre-commit checks have failed. Please run:

uv pip install pre-commit>=4.5.1
pre-commit install
pre-commit run --all-files

Then, commit the changes and push to your branch.

For future commits, pre-commit will run automatically on changed files before each commit.

[srajabos]

pre-commit check is done

[github-actions]

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[skavulya]

LGTM. Thanks @srajabos

[srajabos]

@xinyu-intel , @jikunshang , kindly review

[jikunshang]

actually I feel that all platform should use uint64 as pointer. cuda/rocm may just happen to run. cc @njhill @WoosukKwon
please fix DCO issue, thanks.

[srajabos]

@jikunshang , shall i update this for all platforms?

[jikunshang]

@jikunshang , shall i update this for all platforms?

yes.

[srajabos]

@jikunshang , updated for all platforms