Re: [PATCH v2 2/3] DO NOT MERGE: arm64: perf: Add skip_vmio parameter to control device memory callchain guard

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The commit is explicitly marked 'DO NOT MERGE' and introduces a module parameter to bypass a safety guard, intentionally triggering a kernel panic.
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commit 955a332efd3c97ad086c64a2f8f7a0cd30dbaea7
Author: Fredrik Markstrom <fredrik.markstrom@est.tech>

DO NOT MERGE: arm64: perf: Add skip_vmio parameter to control device memory callchain guard

This commit introduces a module parameter to dynamically disable the device
memory guard during user callchain unwinding. Disabling this guard allows
perf to follow frame pointers into device memory, intentionally triggering a
synchronous external abort and kernel panic on arm64 for testing purposes.

> DO NOT MERGE: arm64: perf: Add skip_vmio parameter to control device memory callchain guard

Should this patch be dropped from the queue, given the subject is explicitly
marked "DO NOT MERGE"?

[ ... ]

> diff --git a/arch/arm64/kernel/stacktrace.c b/arch/arm64/kernel/stacktrace.c
> index 4a28df9bbe763..19b5251f214f2 100644
> --- a/arch/arm64/kernel/stacktrace.c
> +++ b/arch/arm64/kernel/stacktrace.c
> @@ -123,6 +124,10 @@ static bool range_is_device_mem(unsigned long start, unsigned long size)
>  	return false;
>  }
>  
> +static bool skip_vmio = true;
> +module_param_unsafe(skip_vmio, bool, 0600);
> +MODULE_PARM_DESC(skip_vmio, "Skip device memory during user callchain unwinding");
> +

Is it intended to merge this debug module parameter into the mainline kernel?

The commit message notes that disabling this guard intentionally triggers a
synchronous external abort and kernel panic.

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Sashiko AI review · https://sashiko.dev/#/patchset/20260430-master-with-pfix-v3-v2-0-bd526ec04a75@est.tech?part=2