Re: [PATCH] dma-buf: Make DMABUF_DEBUG default to y on DEBUG_KERNEL kernels

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Using DEBUG_KERNEL as a default trigger for DMABUF_DEBUG unintentionally enables performance-degrading debug checks on production kernels.
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commit 35e36d45a9285f1874efd2a5212588eb662aa118
Author: Karl Mehltretter <kmehltretter@gmail.com>

dma-buf: Make DMABUF_DEBUG default to y on DEBUG_KERNEL kernels

This commit replaces the non-existent DEBUG Kconfig symbol with DEBUG_KERNEL
to ensure DMA-BUF debug checks are enabled on debug kernels.

> diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig
> index 7efc0f0d07126..e4f078a326a41 100644
> --- a/drivers/dma-buf/Kconfig
> +++ b/drivers/dma-buf/Kconfig
> @@ -43,7 +43,7 @@ config UDMABUF
>  config DMABUF_DEBUG
>  	bool "DMA-BUF debug checks"
>  	depends on DMA_SHARED_BUFFER
> -	default y if DEBUG
> +	default y if DEBUG_KERNEL

[Severity: Medium]
Will tying this default to DEBUG_KERNEL unintentionally cause a performance
regression on production kernels?

Because DEBUG_KERNEL is a top-level menu toggle enabled in virtually all
production configurations and standard distributions, DMABUF_DEBUG will now
be universally enabled by default.

This introduces unnecessary dynamic heap allocations and scatterlist copying
in dma_buf_map_attachment() via dma_buf_wrap_sg_table() during frequent map
and unmap operations.

Could this be tied to a more specific debugging option instead to prevent
this regression on production systems?

>  	help
>  	  This option enables additional checks for DMA-BUF importers and
>  	  exporters. Specifically it validates that importers do not peek at the

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Sashiko AI review · https://sashiko.dev/#/patchset/20260907020015.24719-1-kmehltretter@gmail.com?part=1