Re: [RFC PATCH v2 07/11] ptwrite uprobes: Add multinop support

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] uprobes: unused ft_off and nft fields in uprobe_ptwrite_arch
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commit 45ecb87404a0455ddedb4d1415f99bbe867523b6
Author: Andi Kleen <ak@kernel.org>

ptwrite uprobes: Add multinop support

This commit introduces support for a %multinop feature in ptwrite uprobes,
which allows users to opt into patching five one-byte NOPs emitted by GCC.
It updates the ptwrite stub generation and the trace_uprobe parser to
handle this new argument.

> diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h
> index e5a668ba5ad6c..c46b3fe090253 100644
> --- a/arch/x86/include/asm/uprobes.h
> +++ b/arch/x86/include/asm/uprobes.h
[ ... ]
> @@ -49,6 +60,9 @@ struct uprobe_ptwrite_arch {
>  	u8	jmp_off;	/* offset of the final jmp's rel32 field */
>  	u8	ndata;		/* number of u64 data slots */
>  	u8	orig[MAX_UINSN_BYTES];	/* pristine file bytes, before generic analysis */
> +	u16	ft_off;		/* fault table offset within the block (0 if none) */
> +	u8	nft;		/* number of fault entries */

[Severity: Low]
Are the ft_off and nft fields necessary? They appear to be completely unused
throughout the entire patch series after being added to struct
uprobe_ptwrite_arch here.

> +	bool	allow_nop_run;	/* accept a five-byte run of 0x90 */
>  };

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Sashiko AI review · https://sashiko.dev/#/patchset/20260917230127.924985-2-ak@kernel.org?part=7